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.circleci/config.yml+24 .gitignore+1 README.md+232−116 RELEASE NOTES.md+1217 circle.yml−12 scrap-your-nils.md+60 squeal-postgresql/README.md+2−155 squeal-postgresql/exe/Example.hs+60−59 squeal-postgresql/squeal-postgresql.cabal+102−32 squeal-postgresql/src/Squeal/PostgreSQL.hs+233−186 squeal-postgresql/src/Squeal/PostgreSQL/Alias.hs+249 squeal-postgresql/src/Squeal/PostgreSQL/Binary.hs+694−109 squeal-postgresql/src/Squeal/PostgreSQL/Definition.hs+30−570 squeal-postgresql/src/Squeal/PostgreSQL/Definition/Function.hs+238 squeal-postgresql/src/Squeal/PostgreSQL/Definition/Index.hs+159 squeal-postgresql/src/Squeal/PostgreSQL/Definition/Schema.hs+96 squeal-postgresql/src/Squeal/PostgreSQL/Definition/Table.hs+500 squeal-postgresql/src/Squeal/PostgreSQL/Definition/Table/Constraint.hs+339 squeal-postgresql/src/Squeal/PostgreSQL/Definition/Type.hs+229 squeal-postgresql/src/Squeal/PostgreSQL/Definition/View.hs+104 squeal-postgresql/src/Squeal/PostgreSQL/Expression.hs+365−990 squeal-postgresql/src/Squeal/PostgreSQL/Expression/Aggregate.hs+462 squeal-postgresql/src/Squeal/PostgreSQL/Expression/Collection.hs+169 squeal-postgresql/src/Squeal/PostgreSQL/Expression/Comparison.hs+206 squeal-postgresql/src/Squeal/PostgreSQL/Expression/Json.hs+462 squeal-postgresql/src/Squeal/PostgreSQL/Expression/Literal.hs+87 squeal-postgresql/src/Squeal/PostgreSQL/Expression/Logic.hs+105 squeal-postgresql/src/Squeal/PostgreSQL/Expression/Math.hs+100 squeal-postgresql/src/Squeal/PostgreSQL/Expression/Null.hs+104 squeal-postgresql/src/Squeal/PostgreSQL/Expression/Parameter.hs+80 squeal-postgresql/src/Squeal/PostgreSQL/Expression/Range.hs+230 squeal-postgresql/src/Squeal/PostgreSQL/Expression/Set.hs+139 squeal-postgresql/src/Squeal/PostgreSQL/Expression/Sort.hs+85 squeal-postgresql/src/Squeal/PostgreSQL/Expression/Subquery.hs+120 squeal-postgresql/src/Squeal/PostgreSQL/Expression/Text.hs+64 squeal-postgresql/src/Squeal/PostgreSQL/Expression/TextSearch.hs+157 squeal-postgresql/src/Squeal/PostgreSQL/Expression/Time.hs+192 squeal-postgresql/src/Squeal/PostgreSQL/Expression/Type.hs+446 squeal-postgresql/src/Squeal/PostgreSQL/Expression/Window.hs+284 squeal-postgresql/src/Squeal/PostgreSQL/List.hs+112 squeal-postgresql/src/Squeal/PostgreSQL/Manipulation.hs+460−268 squeal-postgresql/src/Squeal/PostgreSQL/Migration.hs+448 squeal-postgresql/src/Squeal/PostgreSQL/PG.hs+388 squeal-postgresql/src/Squeal/PostgreSQL/PQ.hs+454−318 squeal-postgresql/src/Squeal/PostgreSQL/Pool.hs+122 squeal-postgresql/src/Squeal/PostgreSQL/Prettyprint.hs−67 squeal-postgresql/src/Squeal/PostgreSQL/Query.hs+802−505 squeal-postgresql/src/Squeal/PostgreSQL/Render.hs+145 squeal-postgresql/src/Squeal/PostgreSQL/Schema.hs+448−262 squeal-postgresql/src/Squeal/PostgreSQL/Transaction.hs+252 squeal-postgresql/test/Doc.hs+6 squeal-postgresql/test/DocTest.hs−14 squeal-postgresql/test/Property.hs+166 squeal-postgresql/test/Spec.hs+136−1 squeal-postgresql/test/Squeal/PostgreSQL/DefinitionSpec.hs−124 squeal-postgresql/test/Squeal/PostgreSQL/ManipulationSpec.hs−128 squeal-postgresql/test/Squeal/PostgreSQL/QuerySpec.hs−181 squeal-presentation-raveline.md+794 squeal-presentation.pdf stack.yaml+6−1
.circleci/config.ymlnew file+24
@@ -0,0 +1,24 @@
1+version: 2
2+jobs:
3+ build:
4+ docker:
5+ - image: haskell:8.6.5
6+ - image: circleci/postgres:latest
7+ environment:
8+ POSTGRES_USER: root
9+ POSTGRES_DB: exampledb
10+ steps:
11+ - checkout
12+ - restore_cache:
13+ keys:
14+ - dependency-cache
15+ - run: apt-get update && apt-get install -y libpq-dev xz-utils make
16+ - run: stack upgrade && stack update
17+ - run: stack build --fast
18+ - run: stack test
19+ - run: stack haddock
20+ - save_cache:
21+ key: dependency-cache
22+ paths:
23+ - ".stack-work"
24+ - "/root/.stack/"
.gitignore+1
@@ -17,3 +17,4 @@ cabal.sandbox.config
1717*.eventlog
1818.stack-work/
1919cabal.project.local
20+.DS_Store
README.md+232−116
@@ -2,7 +2,7 @@
22
33![squeal-icon](http://www.emoticonswallpapers.com/emotion/cute-big-pig/cute-pig-smiley-046.gif)
44
5−[![CircleCI](https://circleci.com/gh/echatav/squeal.svg?style=svg&circle-token=a699a654ef50db2c3744fb039cf2087c484d1226)](https://circleci.com/gh/echatav/squeal)
5+[![CircleCI](https://circleci.com/gh/echatav/squeal.svg?style=svg&circle-token=a699a654ef50db2c3744fb039cf2087c484d1226)](https://circleci.com/gh/morphismtech/squeal)
66
77[Github](https://github.com/morphismtech/squeal)
88
@@ -10,155 +10,271 @@
1010
1111[Stackage](https://www.stackage.org/package/squeal-postgresql)
1212
13+[YouTube](https://www.youtube.com/watch?v=rWfEQfAaNc4)
14+
15+## introduction
16+
17+Squeal is a deep embedding of SQL into Haskell. By "deep embedding", I am abusing the
18+term somewhat. What I mean is that Squeal embeds both SQL terms and SQL types
19+into Haskell at the term and type levels respectively. This leads to a very high level
20+of type-safety in Squeal.
21+
22+Squeal embeds not just the structured query language of SQL but also the
23+data manipulation language and the data definition language; that's `SELECT`,
24+`INSERT`, `UPDATE`, `DELETE`, `WITH`, `CREATE`, `DROP`, and `ALTER` commands.
25+
26+Squeal expressions closely match their corresponding SQL expressions so that
27+the SQL they actually generate is completely predictable. They are also highly
28+composable and cover a large portion of SQL.
29+
30+## features
31+
32+* generic encoding of Haskell tuples and records into query parameters
33+ and generic decoding of query results into Haskell records
34+ using [`generics-sop`](https://hackage.haskell.org/package/generics-sop)
35+* access to SQL alias system using the `OverloadedLabels` extension
36+* type-safe `NULL` and `DEFAULT`
37+* type-safe SQL constraints `CHECK`, `UNIQUE`, `PRIMARY KEY` and `FOREIGN KEY`
38+* type-safe aggregation
39+* escape hatches for writing raw SQL
40+* [`mtl`](https://hackage.haskell.org/package/mtl) compatible monad transformer
41+ for executing as well as preparing queries and manipulations
42+ and [Atkey](https://bentnib.org/paramnotions-jfp.pdf) indexed monad transformer
43+ for executing definitions.
44+* linear, invertible migrations
45+* connection pools
46+* transactions
47+* views
48+* array, composite and enumerated types
49+* json functions and operations
50+* multischema support
51+* correlated subqueries
52+* window functions
53+* text search
54+
1355## installation
1456
1557`stack install squeal-postgresql`
1658
17−## usage
59+## testing
1860
19−Squeal is a deep embedding of PostgreSQL in Haskell. Let's see an example!
61+Start postgres on localhost port `5432` and create a database named `exampledb`.
2062
21−First, we need some language extensions because Squeal uses modern GHC features.
63+`stack test`
2264
23−```haskell
24−{-# LANGUAGE
25− DataKinds
26− , DeriveGeneric
27− , OverloadedLabels
28− , OverloadedStrings
29− , TypeApplications
30− , TypeOperators
31−#-}
32−```
65+## contributing
3366
34−Here comes the Main module and imports.
67+We welcome contributors.
68+Please make pull requests on the `dev` branch instead of `master`.
69+The `Issues` page is a good place to communicate.
3570
36−```haskell
37−module Main (main) where
71+## usage
3872
39−import Control.Monad.Base (liftBase)
40−import Data.Int (Int32)
41−import Data.Text (Text)
73+Let's see an example!
4274
43−import Squeal.PostgreSQL
75+First, we need some language extensions because Squeal uses modern GHC
76+features.
77+
78+```Haskell
79+>>> :set -XDataKinds -XDeriveGeneric -XOverloadedLabels -XFlexibleContexts
80+>>> :set -XOverloadedStrings -XTypeApplications -XTypeOperators -XGADTs
4481```
4582
46−We'll use generics to easily convert between Haskell and PostgreSQL values.
83+We'll need some imports.
4784
48−```haskell
49−import qualified Generics.SOP as SOP
50−import qualified GHC.Generics as GHC
85+```Haskell
86+>>> import Control.Monad.IO.Class (liftIO)
87+>>> import Data.Int (Int32)
88+>>> import Data.Text (Text)
89+>>> import Squeal.PostgreSQL
5190```
5291
53−The first step is to define the schema of our database. This is where we use DataKinds and TypeOperators. The schema consists of a type-level list of tables, a `:::` pairing of a type level string or `Symbol` and a list a columns, itself a `:::` pairing of a `Symbol` and a `ColumnType`. The `ColumnType` describes the PostgreSQL type of the column as well as whether or not it may contain `NULL` and whether or not inserts and updates can use a `DEFAULT`. For our schema, we'll define two tables, a users table and an emails table.
92+We'll use generics to easily convert between Haskell and PostgreSQL values.
5493
55−```haskell
56−type Schema =
57− '[ "users" :::
58− '[ "id" ::: 'Optional ('NotNull 'PGint4)
59− , "name" ::: 'Required ('NotNull 'PGtext)
60− ]
61− , "emails" :::
62− '[ "id" ::: 'Optional ('NotNull 'PGint4)
63− , "user_id" ::: 'Required ('NotNull 'PGint4)
64− , "email" ::: 'Required ('Null 'PGtext)
65− ]
66− ]
94+```Haskell
95+>>> import qualified Generics.SOP as SOP
96+>>> import qualified GHC.Generics as GHC
6797```
6898
69−Next, we'll write Definitions to set up and tear down the schema. In Squeal, a Definition is a `createTable`, `alterTable` or `dropTable` command and has two type parameters, corresponding to the schema before being run and the schema after. We can compose definitions using `>>>`. Here and in the rest of our commands we make use of overloaded labels to refer to named tables and columns in our schema.
70−
71−```haskell
72−setup :: Definition '[] Schema
73−setup =
74− createTable #users
75− ( serial `As` #id :*
76− (text & notNull) `As` #name :* Nil )
77− [ primaryKey (Column #id :* Nil) ]
78− >>>
79− createTable #emails
80− ( serial `As` #id :*
81− (int & notNull) `As` #user_id :*
82− text `As` #email :* Nil )
83− [ primaryKey (Column #id :* Nil)
84− , foreignKey (Column #user_id :* Nil) #users (Column #id :* Nil)
85− OnDeleteCascade OnUpdateCascade ]
99+The first step is to define the schema of our database. This is where
100+we use `DataKinds` and `TypeOperators`.
101+
102+```Haskell
103+>>> :{
104+type UsersColumns =
105+ '[ "id" ::: 'Def :=> 'NotNull 'PGint4
106+ , "name" ::: 'NoDef :=> 'NotNull 'PGtext ]
107+type UsersConstraints = '[ "pk_users" ::: 'PrimaryKey '["id"] ]
108+type EmailsColumns =
109+ '[ "id" ::: 'Def :=> 'NotNull 'PGint4
110+ , "user_id" ::: 'NoDef :=> 'NotNull 'PGint4
111+ , "email" ::: 'NoDef :=> 'Null 'PGtext ]
112+type EmailsConstraints =
113+ '[ "pk_emails" ::: 'PrimaryKey '["id"]
114+ , "fk_user_id" ::: 'ForeignKey '["user_id"] "users" '["id"] ]
115+type Schema =
116+ '[ "users" ::: 'Table (UsersConstraints :=> UsersColumns)
117+ , "emails" ::: 'Table (EmailsConstraints :=> EmailsColumns) ]
118+type Schemas = Public Schema
119+:}
86120```
87121
88−Notice that setup starts with an empty schema `'[]` and produces `Schema`. In our `createTable` commands we included `TableConstraint`s to define primary and foreign keys, making them somewhat complex. Our tear down `Definition` is simpler.
89−
90−```haskell
91−teardown :: Definition Schema '[]
92−teardown = dropTable #emails >>> dropTable #users
122+Notice the use of type operators.
123+
124+`:::` is used to pair an alias `Symbol` with a `SchemumType`,
125+a `TableConstraint` or a `ColumnType`. It is intended to connote Haskell's `::`
126+operator.
127+
128+`:=>` is used to pair `TableConstraints` with a `ColumnsType`,
129+yielding a `TableType`, or to pair a `ColumnConstraint` with a `NullityType`,
130+yielding a `ColumnType`. It is intended to connote Haskell's `=>` operator
131+
132+Next, we'll write `Definition`s to set up and tear down the schema. In
133+Squeal, a `Definition` like `createTable`, `alterTable` or `dropTable`
134+has two type parameters, corresponding to the schema
135+before being run and the schema after. We can compose definitions using `>>>`.
136+Here and in the rest of our commands we make use of overloaded
137+labels to refer to named tables and columns in our schema.
138+
139+```Haskell
140+>>> :{
141+let
142+ setup :: Definition (Public '[]) Schemas
143+ setup =
144+ createTable #users
145+ ( serial `as` #id :*
146+ (text & notNullable) `as` #name )
147+ ( primaryKey #id `as` #pk_users ) >>>
148+ createTable #emails
149+ ( serial `as` #id :*
150+ (int & notNullable) `as` #user_id :*
151+ (text & nullable) `as` #email )
152+ ( primaryKey #id `as` #pk_emails :*
153+ foreignKey #user_id #users #id
154+ OnDeleteCascade OnUpdateCascade `as` #fk_user_id )
155+:}
93156```
94157
95−Next, we'll write `Manipulation`s to insert data into our two tables. A `Manipulation` is an `insertInto`, `update` or `deleteFrom` command and has three type parameters, the schema it refers to, a list of parameters it can take as input, and a list of columns it produces as output. When we insert into the users table, we will need a parameter for the name field but not for the id field. Since it's optional, we can use a default value. However, since the emails table refers to the users table, we will need to retrieve the user id that the insert generates and insert it into the emails table. Take a careful look at the type and definition of both of our inserts.
96−
97−```haskell
98−insertUser :: Manipulation Schema
99− '[ 'Required ('NotNull 'PGtext)]
100− '[ "fromOnly" ::: 'Required ('NotNull 'PGint4) ]
101−insertUser = insertInto #users
102− ( Values (def `As` #id :* param @1 `As` #name :* Nil) [] )
103− OnConflictDoNothing (Returning (#id `As` #fromOnly :* Nil))
104−
105−insertEmail :: Manipulation Schema
106− '[ 'Required ('NotNull 'PGint4), 'Required ('Null 'PGtext)] '[]
107−insertEmail = insertInto #emails ( Values
108− ( def `As` #id :*
109− param @1 `As` #user_id :*
110− param @2 `As` #email :* Nil) [] )
111− OnConflictDoNothing (Returning Nil)
158+We can easily see the generated SQL is unsurprising looking.
159+
160+```Haskell
161+>>> printSQL setup
162+CREATE TABLE "users" ("id" serial, "name" text NOT NULL, CONSTRAINT "pk_users" PRIMARY KEY ("id"));
163+CREATE TABLE "emails" ("id" serial, "user_id" int NOT NULL, "email" text NULL, CONSTRAINT "pk_emails" PRIMARY KEY ("id"), CONSTRAINT "fk_user_id" FOREIGN KEY ("user_id") REFERENCES "users" ("id") ON DELETE CASCADE ON UPDATE CASCADE);
112164```
113165
114−Next we write a `Query` to retrieve users from the database. We're not interested in the ids here, just the usernames and email addresses. We need to use an inner join to get the right result. A `Query` is like a `Manipulation` with the same kind of type parameters.
115−
116−```haskell
117−getUsers :: Query Schema '[]
118− '[ "userName" ::: 'Required ('NotNull 'PGtext)
119− , "userEmail" ::: 'Required ('Null 'PGtext) ]
120−getUsers = select
121− (#u ! #name `As` #userName :* #e ! #email `As` #userEmail :* Nil)
122− ( from (Table (#users `As` #u)
123− & InnerJoin (Table (#emails `As` #e))
124− (#u ! #id .== #e ! #user_id)) )
166+Notice that `setup` starts with an empty schema `'[]` and produces `Schema`.
167+In our `createTable` commands we included `TableConstraint`s to define
168+primary and foreign keys, making them somewhat complex. Our `teardown`
169+`Definition` is simpler.
170+
171+```Haskell
172+>>> :{
173+let
174+ teardown :: Definition Schemas (Public '[])
175+ teardown = dropTable #emails >>> dropTable #users
176+:}
177+
178+>>> printSQL teardown
179+DROP TABLE "emails";
180+DROP TABLE "users";
125181```
126182
127−Now that we've defined the SQL side of things, we'll need a Haskell type for users. We give the type `Generic` and `HasDatatypeInfo` instances so that we can decode the rows we receive when we run getUsers. Notice that the record fields of the `User` type match the column names of `getUsers`.
183+We'll need a Haskell type for `User`s. We give the type `SOP.Generic` and
184+`SOP.HasDatatypeInfo` instances so that we can encode and decode `User`s.
128185
129−```haskell
130−data User = User { userName :: Text, userEmail :: Maybe Text }
131− deriving (Show, GHC.Generic)
132−instance SOP.Generic User
133−instance SOP.HasDatatypeInfo User
186+```Haskell
187+>>> data User = User { userName :: Text, userEmail :: Maybe Text } deriving (Show, GHC.Generic)
188+>>> instance SOP.Generic User
189+>>> instance SOP.HasDatatypeInfo User
134190```
135191
136−Let's also create some users to add to the database.
192+Next, we'll write `Manipulation_`s to insert `User`s into our two tables.
193+A `Manipulation_` like `insertInto`, `update` or `deleteFrom`
194+has three type parameters, the schemas it refers to, input parameters
195+and an output row. When
196+we insert into the users table, we will need a parameter for the `name`
197+field but not for the `id` field. Since it's serial, we can use a default
198+value. However, since the emails table refers to the users table, we will
199+need to retrieve the user id that the insert generates and insert it into
200+the emails table. We can do this in a single `Manipulation_` by using a
201+`with` statement.
202+
203+```Haskell
204+>>> :{
205+let
206+ insertUser :: Manipulation_ Schemas User ()
207+ insertUser = with (u `as` #u) e
208+ where
209+ u = insertInto #users
210+ (Values_ (Default `as` #id :* Set (param @1) `as` #name))
211+ OnConflictDoRaise (Returning_ (#id :* param @2 `as` #email))
212+ e = insertInto_ #emails $ Select
213+ (Default `as` #id :* Set (#u ! #id) `as` #user_id :* Set (#u ! #email) `as` #email)
214+ (from (common #u))
215+:}
216+
217+>>> printSQL insertUser
218+WITH "u" AS (INSERT INTO "users" ("id", "name") VALUES (DEFAULT, ($1 :: text)) RETURNING "id" AS "id", ($2 :: text) AS "email") INSERT INTO "emails" ("user_id", "email") SELECT "u"."id", "u"."email" FROM "u" AS "u"
219+```
137220
138−```haskell
139−users :: [User]
140−users =
141− [ User "Alice" (Just "alice@gmail.com")
142− , User "Bob" Nothing
143− , User "Carole" (Just "carole@hotmail.com")
144− ]
221+Next we write a `Query_` to retrieve users from the database. We're not
222+interested in the ids here, just the usernames and email addresses. We
223+need to use an `innerJoin` to get the right result. A `Query_` is like a
224+`Manipulation_` with the same kind of type parameters.
225+
226+```Haskell
227+>>> :{
228+let
229+ getUsers :: Query_ Schemas () User
230+ getUsers = select_
231+ (#u ! #name `as` #userName :* #e ! #email `as` #userEmail)
232+ ( from (table (#users `as` #u)
233+ & innerJoin (table (#emails `as` #e))
234+ (#u ! #id .== #e ! #user_id)) )
235+:}
236+
237+>>> printSQL getUsers
238+SELECT "u"."name" AS "userName", "e"."email" AS "userEmail" FROM "users" AS "u" INNER JOIN "emails" AS "e" ON ("u"."id" = "e"."user_id")
145239```
146240
147−Now we can put together all the pieces into a program. The program connects to the database, sets up the schema, inserts the user data (using prepared statements as an optimization), queries the user data and prints it out and finally closes the connection. We can thread the changing schema information through by using the indexed `PQ` monad transformer and when the schema doesn't change we can use `Monad` and `MonadPQ` functionality.
241+Let's create some users to add to the database.
242+
243+```Haskell
244+>>> :{
245+let
246+ users :: [User]
247+ users =
248+ [ User "Alice" (Just "alice@gmail.com")
249+ , User "Bob" Nothing
250+ , User "Carole" (Just "carole@hotmail.com")
251+ ]
252+:}
253+```
148254
149−```haskell
150−main :: IO ()
151−main = void $
152− withConnection "host=localhost port=5432 dbname=exampledb" . runPQ $
255+Now we can put together all the pieces into a program. The program
256+connects to the database, sets up the schema, inserts the user data
257+(using prepared statements as an optimization), queries the user
258+data and prints it out and finally closes the connection. We can thread
259+the changing schema information through by using the indexed `PQ` monad
260+transformer and when the schema doesn't change we can use `Monad` and
261+`MonadPQ` functionality.
262+
263+```Haskell
264+>>> :{
265+let
266+ session :: PQ Schemas Schemas IO ()
267+ session = do
268+ _ <- traversePrepared_ insertUser users
269+ usersResult <- runQuery getUsers
270+ usersRows <- getRows usersResult
271+ liftIO $ print (usersRows :: [User])
272+in
273+ withConnection "host=localhost port=5432 dbname=exampledb" $
153274 define setup
154275 & pqThen session
155− & thenDefine teardown
156− where
157− session = do
158− idResults <- traversePrepared insertUser (Only . userName <$> users)
159− ids <- traverse (fmap fromOnly . getRow (RowNumber 0)) idResults
160− traversePrepared_ insertEmail (zip (ids :: [Int32]) (userEmail <$> users))
161− usersResult <- runQuery getUsers
162− usersRows <- getRows usersResult
163− liftBase $ print (usersRows :: [User])
276+ & pqThen (define teardown)
277+:}
278+[User {userName = "Alice", userEmail = Just "alice@gmail.com"},User {userName = "Bob", userEmail = Nothing},User {userName = "Carole", userEmail = Just "carole@hotmail.com"}]
279+-}
164280```
RELEASE NOTES.mdnew file+1217
@@ -0,0 +1,1217 @@
1+## RELEASE NOTES
2+
3+### Version 0.5
4+
5+Version 0.5 makes a number of large changes and additions to Squeal.
6+I want to thank folks who contributed issues and pull requests;
7+Raveline, rimmington, ilyakooo0, chshersh, reygoch, and more.
8+
9+**Multi-schema support**
10+
11+Previous versions of Squeal only supported definitions in the "public"
12+schema. Squeal 0.5 adds support for multiple schemas with the new kind
13+
14+```Haskell
15+type SchemasType = [(Symbol,SchemaType)]
16+```
17+
18+In order to upgrade your queries, manipulations and definitions from
19+Squeal 0.4, you will have to apply the `Public` type family, which indicates
20+that your only schema is the "public" schema.
21+
22+```Haskell
23+-- Squeal 0.4
24+setup :: Definition '[] Schema
25+
26+-- Squeal 0.5
27+setup :: Definition (Public '[]) (Public Schema)
28+```
29+
30+You can create non-public schemas using `createSchema` and inversely
31+remove them using `dropSchema`. There is also an idempotent
32+`createSchemaIfNotExists`.
33+
34+In order to handle aliases which may refer to non-public schemas, Squeal 0.5
35+introduces `QualifiedAlias`es. A `QualifiedAlias` can be referred to using
36+the `(!)` operator from the `IsQualified` typeclass; but if you want to refer
37+to an alias from the "public" schema, you can continue to use a single
38+overloaded label, no need to write `#public ! #tab`, just write `#tab`.
39+
40+**Top-level statements**
41+
42+As a consequence of multi-schema support, common table expressions that
43+a `Query` or `Manipulation` may refer to had to be broken into a new parameter.
44+Additionally, `Query` gained another new parameter for its outer scope which
45+will be discussed in the next section.
46+
47+To simplify type signatures that you have to write for top-level queries
48+and manipulations, Squeal 0.5 introduces the `Query_` and `Manipulation_`
49+type families.
50+
51+```
52+type family Query_
53+ (schemas :: SchemasType)
54+ (parameters :: Type)
55+ (row :: Type) where
56+ Query_ schemas params row =
57+ Query '[] '[] schemas (TuplePG params) (RowPG row)
58+```
59+
60+As you see, a top-level `Query_` has no outer scope and no common
61+table expressions in scope, they are empty `'[]`. Moreover,
62+its parameters and row parameters are now `Type`s, which are
63+converted to corresponding Postgres types using the `TuplePG`
64+and `RowPG` type families. This means you can write the type signatures
65+for your top-level statements using the Haskell types that you
66+intend to input and retrieve when running the statements. Similar
67+to `Query_`, there is a `Manipulation_` type, the only difference
68+being that a general `Manipulation` doesn't have an outer scope,
69+only a scope for common table expressions.
70+
71+**Subquery expressions**
72+
73+Previous versions of Squeal offered subquery expression support
74+but there were issues. The common use case of using the `IN` operator
75+from SQL was overly complex. There was a proliferation of subquery
76+functions to handle different comparison operators, each with two versions
77+for comparing `ALL` or `ANY` of the query rows. And, most confoundedly,
78+there was no way to support the `EXISTS` subquery because the "outer scope"
79+for a query was not available.
80+
81+Squeal adds an outer scope to the `Query` type.
82+
83+```Haskell
84+newtype Query
85+ (outer :: FromType)
86+ (commons :: FromType)
87+ (schemas :: SchemasType)
88+ (params :: [NullityType])
89+ (row :: RowType)
90+ = UnsafeQuery { renderQuery :: ByteString }
91+```
92+
93+This enables a well-typed `exists` function.
94+
95+```Haskell
96+exists
97+ :: Query (Join outer from) commons schemas params row
98+ -> Condition outer commons grp schemas params from
99+```
100+
101+The `in_` and `notIn` functions were simplified to handle the most
102+common use case of comparing to a list of values.
103+
104+```Haskell
105+in_
106+ :: Expression outer commons grp schemas params from ty -- ^ expression
107+ -> [Expression outer commons grp schemas params from ty]
108+ -> Condition outer commons grp schemas params from
109+```
110+
111+Finally, general subquery comparisons were abstracted to work with
112+any comparison operators, using the `Operator` type which will be discussed in
113+the next section.
114+
115+```Haskell
116+subAll
117+ :: Expression outer commons grp schemas params from ty1
118+ -> Operator ty1 ty2 ('Null 'PGbool)
119+ -> Query (Join outer from) commons schemas params '[col ::: ty2]
120+ -> Condition outer commons grp schemas params from
121+
122+subAny
123+ :: Expression outer commons grp schemas params from ty1
124+ -> Operator ty1 ty2 ('Null 'PGbool)
125+ -> Query (Join outer from) commons schemas params '[col ::: ty2]
126+ -> Condition outer commons grp schemas params from
127+```
128+
129+**Expression RankNTypes**
130+
131+Squeal 0.5 introduces RankNType type synonyms for common expression patterns.
132+The simplest example is the `Expr` type, a type for "closed" expressions
133+that cannot reference any aliases or parameters.
134+
135+```Haskell
136+type Expr x
137+ = forall outer commons grp schemas params from
138+ . Expression outer commons grp schemas params from x
139+```
140+
141+There is also a function type `(-->)`, which is a subtype of the usual Haskell function
142+type `(->)`.
143+
144+```Haskell
145+type (-->) x y
146+ = forall outer commons grp schemas params from
147+ . Expression outer commons grp schemas params from x
148+ -> Expression outer commons grp schemas params from y
149+```
150+
151+We saw in the subquery section that there is an `Operator` type.
152+
153+```Haskell
154+type Operator x1 x2 y
155+ = forall outer commons grp schemas params from
156+ . Expression outer commons grp schemas params from x1
157+ -> Expression outer commons grp schemas params from x2
158+ -> Expression outer commons grp schemas params from y
159+```
160+
161+There are also types `FunctionN` and `FunctionVar` for n-ary functions
162+and variadic functions.
163+
164+```
165+type FunctionN xs y
166+ = forall outer commons grp schemas params from
167+ . NP (Expression outer commons grp schemas params from) xs
168+ -> Expression outer commons grp schemas params from y
169+```
170+
171+An n-ary function takes an `NP` list of `Expression`s as its argument.
172+Squeal 0.5 adds a helpful operator `(*:)`, to help scrap your `Nil`s.
173+You can construct an `NP` list now by using the operator `(:*)`,
174+until your last element, using `(*:)` there. For instance, the function
175+`atan2_` takes two arguments, `atan2_ (pi *: 2)`.
176+
177+**Selections**
178+
179+Previously, Squeal provided a couple versions of `SELECT` depending
180+on whether you wanted to select all columns of a unique table
181+in the from clause, i.e. `*`, all columns of a particular table
182+in the from clause, i.e. `.*`, or a list of columns from the from clause.
183+
184+Squeal 0.5 refactors this pattern into a `Selection` GADT type, allowing
185+for abstraction and combinations that were not possible before.
186+
187+```Haskell
188+data Selection outer commons grp schemas params from row where
189+ Star
190+ :: HasUnique tab from row
191+ => Selection outer commons 'Ungrouped schemas params from row
192+ DotStar
193+ :: Has tab from row
194+ => Alias tab
195+ -> Selection outer commons 'Ungrouped schemas params from row
196+ List
197+ :: SListI row
198+ => NP (Aliased (Expression outer commons grp schemas params from)) row
199+ -> Selection outer commons grp schemas params from row
200+ Over
201+ :: SListI row
202+ => NP (Aliased (WindowFunction outer commons grp schemas params from)) row
203+ -> WindowDefinition outer commons grp schemas params from
204+ -> Selection outer commons grp schemas params from row
205+ Also
206+ :: Selection outer commons grp schemas params from right
207+ -> Selection outer commons grp schemas params from left
208+ -> Selection outer commons grp schemas params from (Join left right)
209+```
210+
211+In addition to the `Star`, `DotStar` and `List` constructors, there is an
212+`Also` constructor combinator, which enables users to combine `Selection`s.
213+Additionally, there is an `Over` constructor that is used to enable
214+window functions, described in the next section.
215+
216+To upgrade from Squeal 0.4, you will replace `selectStar` with `select Star`,
217+replace `selectDotStar #tab` with `select (DotStar #tab)`. The `List`
218+selection is such a common use case that there is a function `select_` which
219+automatically applies it, so to upgrade from Squeal 0.4, replace `select`
220+with `select_`. There are also independent `selectDistinct` and `selectDistinct_`
221+functions to filter out duplicate rows.
222+
223+**Query clauses**
224+
225+Previously, Squeal provided a couple versions of `INSERT` depending
226+on whether you wanted to insert `VALUES` or a query.
227+
228+Squeal 0.5 refactors this pattern into a `QueryClause` GADT.
229+
230+```
231+-- Squeal 0.4
232+insertRow_ #tab (Set 2 `as` #col1 :* Default `as` #col2)
233+insertQuery_ #tab (selectStar (from (table #other_tab)))
234+
235+-- Squeal 0.5
236+insertInto_ #tab (Values_ (Set 2 `as` #col1 :* Default `as` #col2))
237+insertInto_ #tab (Subquery (select Star (from (table #other_tab))))
238+```
239+
240+**Window functions and aggregation**
241+
242+Previous versions of Squeal provided no support for window functions.
243+Squeal 0.5 adds support for window functions. We saw `Over` in the
244+previous section.
245+
246+```Haskell
247+Over
248+ :: SListI row
249+ => NP (Aliased (WindowFunction outer commons grp schemas params from)) row
250+ -> WindowDefinition outer commons grp schemas params from
251+ -> Selection outer commons grp schemas params from row
252+```
253+
254+`Over` combines window functions with window definitions. A `WindowDefinition`
255+is constructed using the `partitionBy` function, optionally with an `orderBy`
256+clause. For example,
257+
258+```Haskell
259+query :: Query_ (Public Schema) () (Row Int32 Int32)
260+query = select
261+ (#col1 & Also (rank `as` #col2 `Over` (partitionBy #col1 & orderBy [#col2 & Asc])))
262+ (from (table #tab))
263+```
264+
265+Here the `rank` function is a `WindowFunction`
266+
267+```Haskell
268+rank :: WinFun0 ('NotNull 'PGint8)
269+rank = UnsafeWindowFunction "rank()"
270+```
271+
272+`WinFun0` is a RankNType, like `Expr` was, used for no argument window functions.
273+Similarly, there are also `WinFun1` and `WinFunN` types for
274+window functions and n-ary window functions.
275+
276+In order to use the same syntax for certain window functions and aggregate functions,
277+a new typeclass `Aggregate` was introduced. So for instance, `sum_` can be
278+either a `Distinction` `Expression` or a `WindowFunction`, used either with
279+a `groupBy` or with a `partitionBy` in the appropriate way.
280+
281+```
282+data Distinction (expr :: kind -> Type) (ty :: kind)
283+ = All (expr ty)
284+ | Distinct (expr ty)
285+```
286+
287+Aggregate functions can be run over all rows or only over distinct rows,
288+while window functions bear no such distinction.
289+
290+**Migrations**
291+
292+Thanks to [https://github.com/Raveline](Raveline) Squeal 0.5 introduces
293+a function `defaultMain` to easily create a command line program to
294+run or rewind your migrations.
295+
296+Previously, Squeal's migrations were impure, allowing in addition to
297+running `Definition`s to run arbitrary `IO` operations, such as inserting
298+data into the database or printing out status messages. In order to
299+provide compatibility with other migration systems, Squeal 0.5 introduces
300+pure migrations, that is migrations that are only `Definition`s.
301+
302+```Haskell
303+data Migration p schemas0 schemas1 = Migration
304+ { name :: Text -- ^ The `name` of a `Migration`.
305+ -- Each `name` in a `Migration` should be unique.
306+ , up :: p schemas0 schemas1 -- ^ The `up` instruction of a `Migration`.
307+ , down :: p schemas1 schemas0 -- ^ The `down` instruction of a `Migration`.
308+ } deriving (GHC.Generic)
309+```
310+
311+A pure migration is a `Migration Definition`, a pair of inverse
312+`Definition`s with a unique name. To recover impure migrations, Squeal 0.5
313+introduces the `Terminally` type.
314+
315+```Haskell
316+newtype Terminally trans monad x0 x1 = Terminally
317+ { runTerminally :: trans x0 x1 monad () }
318+```
319+
320+`Terminally` applies the indexed monad transformer and the monad it transforms
321+to the unit type `()`, thereby turning an indexed monad into a `Category`. An
322+impure migration is a `Migration (Terminally PQ IO)`. You can always cast
323+a pure migration into an impure migration with the functor, `pureMigration`.
324+
325+```Haskell
326+pureMigration
327+ :: Migration Definition schemas0 schemas1
328+ -> Migration (Terminally PQ IO) schemas0 schemas1
329+```
330+
331+To run either pure or impure migrations, Squeal 0.5 introduces
332+a typeclass, `Migratory`.
333+
334+```
335+class Category p => Migratory p where
336+
337+ migrateUp
338+ :: AlignedList (Migration p) schemas0 schemas1
339+ -> PQ schemas0 schemas1 IO ()
340+
341+ migrateDown
342+ :: AlignedList (Migration p) schemas0 schemas1
343+ -> PQ schemas1 schemas0 IO ()
344+```
345+
346+The signatures of `migrateUp` and `migrateDown` have been changed
347+to make them easier to compose with other `PQ` actions.
348+
349+**Transactions**
350+
351+You can now run transactions `ephemerally`, guaranteed to roll back,
352+but return the result or throw the exception that the transaction
353+would have generated. This is useful for testing. You can also
354+`transactionallyRetry` computations, retrying the transaction if
355+a [serialization failure](https://www.postgresql.org/docs/11/transaction-iso.html#XACT-REPEATABLE-READ) occurs.
356+
357+**Types**
358+
359+Squeal now supports money via a `Money` Haskell `Type` and a `'PGmoney`
360+`PGType`. Squeal 0.5 also adds support for creating domain types
361+with `createDomain`.
362+
363+**Time**
364+
365+Squeal 0.5 adds support for new functions; `now`, `makeDate`, `makeTime`,
366+, `makeTimestamp`, and `makeTimestamptz`, a function `interval_` for
367+constructing time intervals out multiples of `TimeUnit`s, and a new
368+`TimeOp` class, defining affine space operators for time types and their
369+differences.
370+
371+**Literals**
372+
373+Squeal allows you to include Haskell values in your statements using
374+out of line `parameter`s, but often you want to include them inline,
375+as a SQL `literal`. Squeal 0.5 enables this using the `Literal` class.
376+
377+**Set returning functions**
378+
379+Squeal 0.5 adds support for set returning functions such as `unnest`,
380+with the `RankNType` `SetOfFunction`, which can be used as as a `FromClause`.
381+
382+**Text search**
383+
384+Squeal 0.5 adds extensive support for text search types, functions and operators.
385+
386+**Much more**
387+
388+Lots more changes went into and under the hood of the new version.
389+The `Expression` module was split into coherent submodules since it
390+had grown to immense proportions. New modules `Alias`, `PG` and `List`
391+were added to relieve some of the burden that the `Schema` module
392+had been carrying. Rendering has been better unified with a new
393+`RenderSQL` typeclass. Type level list concatenation with the `Additional`
394+typeclass has been added. `Manipulation`s `update` and `delete`
395+were upgraded, so you can leave out fields you don't want to update and
396+use `USING` clauses in deletes. Upserts which were previously broken
397+now work. The `IO` typeclass hierarchy was changed from `MonadBase`
398+and `MonadBaseControl` to `MonadIO` and `MonadUnliftIO`. A new
399+`withRecursive` `Manipulation` was added. `SquealException`s were
400+refactored and a `trySqueal` function added. Arrays were refactored.
401+And there was probably more I've forgotten.
402+
403+### Version 0.4
404+
405+Version 0.4 strengthens Squeal's type system, adds
406+support for multidimensional arrays, improves support
407+for container type, improves `with` statements,
408+improves runtime exceptions, accomodates SQL's three-valued logic,
409+adds subquery expressions, and adds table and view type expressions.
410+
411+**Types**
412+
413+Squeal 0.4 renames some kinds to aid intuition:
414+
415+```Haskell
416+type RowType = [(Symbol, NullityType)] -- previously RelationType
417+type FromType = [(Symbol, RowType)] -- previously RelationsType
418+```
419+
420+Null safety for array and composite types is gained by having the base
421+type of an array be a `NullityType` and the base type of a composite
422+a `RowType`.
423+
424+```Haskell
425+data PGType
426+ = ..
427+ | PGvararray NullityType
428+ | PGfixarray Nat NullityType
429+ | PGcomposite RowType
430+```
431+
432+Squeal embeds Postgres types into Haskell using data kinds and type-in-type:
433+
434+```Haskell
435+data PGType = PGbool | ..
436+data NullityType = Null PGType | NotNull PGType
437+type RowType = [(Symbol, NullityType)] -- previously RelationType
438+type FromType = [(Symbol, RowType)] -- previously RelationsType
439+```
440+
441+In another sense, we can embed Haskell types
442+into Postgres types by providing type families:
443+
444+```Haskell
445+type family PG (hask :: Type) :: PGType
446+type family NullPG (hask :: Type) :: NullityType
447+type family TuplePG (hask :: Type) :: [NullityType]
448+type family RowPG (hask :: Type) :: RowType
449+```
450+
451+Let's look at these one by one.
452+
453+`PG` was introduced in Squeal 0.3. It was a closed type family that
454+associates some Haskell types to their obvious corresponding Postgres
455+types like `PG Double = 'PGfloat8`. It only worked on base types,
456+no arrays or composites. Squeal 0.4 extends it to
457+such container types and makes it an open type family so that
458+users can make their own type instances.
459+
460+`NullPG` had a different name before but it does the obvious
461+thing for Haskell with `Maybe`s:
462+
463+```Haskell
464+type family NullPG hask where
465+ NullPG (Maybe hask) = 'Null (PG hask)
466+ NullPG hask = 'NotNull (PG hask)
467+```
468+
469+`TuplePG` uses generics to turn tuple types (including records)
470+into lists of `NullityType`s in the logical way, e.g.
471+`TuplePG (Bool, Day) = '[ 'PGbool, 'PGdate]`.
472+
473+`RowPG` also uses generics to turn record types into a `RowType` in the logical way, e.g.
474+
475+```Haskell
476+>>> data Person = Person { name :: Text, age :: Int32 } deriving GHC.Generic
477+>>> instance SOP.Generic Person
478+>>> instance SOP.HasDatatypeInfo Person
479+>>> :kind! TuplePG Person
480+TuplePG Person :: [NullityType]
481+= '['NotNull 'PGtext, 'NotNull 'PGint4]
482+>>> :kind! RowPG Person
483+RowPG Person :: [(Symbol, NullityType)]
484+= '["name" ::: 'NotNull 'PGtext, "age" ::: 'NotNull 'PGint4]
485+```
486+
487+We've already seen a hint of why these types are useful in one construction
488+from Squeal 0.3. Creating composite types in Postgres directly from a Haskell
489+record type essentially uses `RowPG`. Another important use is in simplifying
490+the type signatures for a `Query` or `Manipulation`. Very often, you will have
491+a tuple type corresponding to the parameters and a record type corresponding
492+to the returned columns of a `Query` or `Manipulation`. Instead of writing
493+boilerplate signature you can reuse these with the help of `TuplePG` and `RowPG`
494+
495+For instance:
496+
497+```Haskell
498+>>> :{
499+let
500+ query :: Query '["user" ::: 'View (RowPG Person)] (TuplePG (Only Int32)) (RowPG Person)
501+ query = selectStar (from (view #user) & where_ (#age .> param @1))
502+:}
503+```
504+
505+**Arrays**
506+
507+In addition to being able to encode and decode basic Haskell types
508+like `Int16` and `Text`, Squeal 0.4 permits you to encode and decode Haskell types to
509+Postgres array types. The `Vector` type corresponds to to variable length arrays.
510+And thanks to an idea from [Mike Ledger](https://github.com/mikeplus64),
511+homogeneous tuples correspond to fixed length arrays. We can even
512+create multi-dimensional fixed length arrays. Let's see an example.
513+
514+```Haskell
515+>>> :{
516+data Row = Row
517+ { col1 :: Vector Int16
518+ , col2 :: (Maybe Int16,Maybe Int16)
519+ , col3 :: ((Int16,Int16),(Int16,Int16),(Int16,Int16))
520+ } deriving (Eq, GHC.Generic)
521+:}
522+
523+>>> instance Generic Row
524+>>> instance HasDatatypeInfo Row
525+```
526+
527+Define a simple round trip query.
528+
529+```Haskell
530+>>> :{
531+let
532+ roundTrip :: Query '[] (TuplePG Row) (RowPG Row)
533+ roundTrip = values_ $
534+ parameter @1 (int2 & vararray) `as` #col1 :*
535+ parameter @2 (int2 & fixarray @2) `as` #col2 :*
536+ parameter @3 (int2 & fixarray @2 & fixarray @3) `as` #col3
537+:}
538+
539+>>> :set -XOverloadedLists
540+>>> let input = Row [1,2] (Just 1,Nothing) ((1,2),(3,4),(5,6))
541+>>> :{
542+void . withConnection "host=localhost port=5432 dbname=exampledb" $ do
543+ result <- runQueryParams roundTrip input
544+ Just output <- firstRow result
545+ liftBase . print $ input == output
546+:}
547+True
548+```
549+
550+**Containers**
551+
552+Squeal aims to provide a correspondence between Haskell types and Postgres types.
553+In particular, Haskell ADTs with nullary constructors can correspond to
554+Postgres enum types and Haskell record types can correspond to Postgres
555+composite types. However, it's not always obvious that that's how a user
556+will choose to store values of those types. So Squeal 0.4 introduces newtypes
557+whose purpose is to specify how a user wants to store values of a type.
558+
559+```Haskell
560+newtype Json hask = Json {getJson :: hask}
561+newtype Jsonb hask = Jsonb {getJsonb :: hask}
562+newtype Composite record = Composite {getComposite :: record}
563+newtype Enumerated enum = Enumerated {getEnumerated :: enum}
564+```
565+
566+Let's see an example:
567+
568+```Haskell
569+>>> data Schwarma = Beef | Lamb | Chicken deriving (Eq, Show, GHC.Generic)
570+>>> instance SOP.Generic Schwarma
571+>>> instance SOP.HasDatatypeInfo Schwarma
572+>>>
573+>>> data Person = Person {name :: Text, age :: Int32} deriving (Eq, Show, GHC.Generic)
574+>>> instance SOP.Generic Person
575+>>> instance SOP.HasDatatypeInfo Person
576+>>> instance Aeson.FromJSON Person
577+>>> instance Aeson.ToJSON Person
578+```
579+
580+We can create the equivalent Postgres types directly from their Haskell types.
581+
582+```Haskell
583+>>> :{
584+type Schema =
585+ '[ "schwarma" ::: 'Typedef (PG (Enumerated Schwarma))
586+ , "person" ::: 'Typedef (PG (Composite Person))
587+ ]
588+:}
589+
590+>>> :{
591+let
592+ setup :: Definition '[] Schema
593+ setup =
594+ createTypeEnumFrom @Schwarma #schwarma >>>
595+ createTypeCompositeFrom @Person #person
596+:}
597+```
598+
599+Let's demonstrate how to associate our Haskell types `Schwarma` and `Person`
600+with enumerated, composite or json types in Postgres. First create a Haskell
601+`Row` type using the `Enumerated`, `Composite` and `Json` newtypes as fields.
602+
603+```Haskell
604+>>> :{
605+data Row = Row
606+ { schwarma :: Enumerated Schwarma
607+ , person1 :: Composite Person
608+ , person2 :: Json Person
609+ } deriving (Eq, GHC.Generic)
610+:}
611+
612+>>> instance Generic Row
613+>>> instance HasDatatypeInfo Row
614+>>> :{
615+let
616+ input = Row
617+ (Enumerated Chicken)
618+ (Composite (Person "Faisal" 24))
619+ (Json (Person "Ahmad" 48))
620+:}
621+```
622+
623+Once again, define a round trip query.
624+
625+```Haskell
626+>>> :{
627+let
628+ roundTrip :: Query Schema (TuplePG Row) (RowPG Row)
629+ roundTrip = values_ $
630+ parameter @1 (typedef #schwarma) `as` #schwarma :*
631+ parameter @2 (typedef #person) `as` #person1 :*
632+ parameter @3 json `as` #person2
633+:}
634+```
635+
636+Finally, we can drop our type definitions.
637+
638+```Haskell
639+>>> :{
640+let
641+ teardown :: Definition Schema '[]
642+ teardown = dropType #schwarma >>> dropType #person
643+:}
644+```
645+
646+Now let's run it.
647+
648+```Haskell
649+>>> :{
650+let
651+ session = do
652+ result <- runQueryParams roundTrip input
653+ Just output <- firstRow result
654+ liftBase . print $ input == output
655+in
656+ void . withConnection "host=localhost port=5432 dbname=exampledb" $
657+ define setup
658+ & pqThen session
659+ & pqThen (define teardown)
660+:}
661+True
662+```
663+
664+**With**
665+
666+Squeal 0.3 supported WITH statements but there's a couple problems with them.
667+Here's the type signature for `with` in Squeal 0.3.
668+
669+```Haskell
670+with
671+ :: SOP.SListI commons
672+ => NP (Aliased (Manipulation schema params)) (common ': commons)
673+ -- ^ common table expressions
674+ -> Manipulation (With (common ': commons) schema) params results
675+ -> Manipulation schema params results
676+```
677+
678+The first problem is that `with` only works with `Manipulations`.
679+It can work on `Query`s by using `queryStatement` but it still will
680+return a `Manipulation`. We can fix this issue by making `with` a
681+method of a type class with instances for both `Query` and `Manipulation`.
682+
683+The second problem is that all the common table expressions
684+refer the base schema, whereas in SQL, each subsequent CTE can
685+refer to previous CTEs as well. But this can be fixed! First define a datatype:
686+
687+```Haskell
688+data CommonTableExpression statement params schema0 schema1 where
689+ CommonTableExpression
690+ :: Aliased (statement schema params) (alias ::: cte)
691+ -> CommonTableExpression statement params schema (alias ::: 'View cte ': schema)
692+```
693+
694+It's just a wrapper around an aliased statement, where the statement
695+could be either a `Query` or `Manipulation`, but it augments the schema
696+by adding a view to it. It almost looks like a morphism between schemas
697+but there is no way yet to compose them. Luckily, Squeal already has
698+a datatype for this, which is used for migrations, the `AlignedList`
699+type which is really the "free category". So we can then define a `With` type class:
700+
701+```Haskell
702+class With statement where
703+ with
704+ :: AlignedList (CommonTableExpression statement params) schema0 schema1
705+ -> statement schema1 params row
706+ -> statement schema0 params row
707+```
708+
709+By giving `Aliasable` instances to CTEs and aligned singleton lists of CTEs (i.e. scrap-your-nils), we get a nice syntax for WITH statements in Squeal.
710+
711+Here's an example of using `with` for a `Query` and a `Manipulation`:
712+
713+```Haskell
714+>>> :{
715+let
716+ query :: Query
717+ '[ "t1" ::: 'View
718+ '[ "c1" ::: 'NotNull 'PGtext
719+ , "c2" ::: 'NotNull 'PGtext] ]
720+ '[]
721+ '[ "c1" ::: 'NotNull 'PGtext
722+ , "c2" ::: 'NotNull 'PGtext ]
723+ query = with (
724+ selectStar (from (view #t1)) `as` #t2 :>>
725+ selectStar (from (view #t2)) `as` #t3
726+ ) (selectStar (from (view #t3)))
727+in printSQL query
728+:}
729+WITH "t2" AS (SELECT * FROM "t1" AS "t1"), "t3" AS (SELECT * FROM "t2" AS "t2") SELECT * FROM "t3" AS "t3"
730+
731+>>> type ProductsTable = '[] :=> '["product" ::: 'NoDef :=> 'NotNull 'PGtext, "date" ::: 'Def :=> 'NotNull 'PGdate]
732+
733+>>> :{
734+let
735+ manipulation :: Manipulation
736+ '[ "products" ::: 'Table ProductsTable
737+ , "products_deleted" ::: 'Table ProductsTable
738+ ] '[ 'NotNull 'PGdate] '[]
739+ manipulation = with
740+ (deleteFrom #products (#date .< param @1) ReturningStar `as` #deleted_rows)
741+ (insertQuery_ #products_deleted (selectStar (from (view (#deleted_rows `as` #t)))))
742+in printSQL manipulation
743+:}
744+WITH "deleted_rows" AS (DELETE FROM "products" WHERE ("date" < ($1 :: date)) RETURNING *) INSERT INTO "products_deleted" SELECT * FROM "deleted_rows" AS "t"
745+```
746+
747+**Three Valued Logic**
748+
749+In previous versions of Squeal, conditions followed classical two valued logic
750+of `true` and `false`.
751+
752+```Haskell
753+-- Squeal 0.3
754+type Condition schema from grouping params =
755+ Expression schema from grouping params ('NotNull 'PGbool)
756+```
757+
758+I had thought that three valued logic, which is what SQL uses, was confusing.
759+However, multiple users reported being confused at being forced to do `NULL`
760+handling, particularly in their left joins. Since the original motivation
761+of being less confusing evaporated I decided to switch to three valued logic
762+of `true`, `false` and `null_`.
763+
764+```Haskell
765+-- Squeal 0.4
766+type Condition schema from grouping params =
767+ Expression schema from grouping params ('Null 'PGbool)
768+```
769+
770+**Subquery Expressions**
771+
772+Squeal 0.4 adds support for subquery expressions such as `IN` and `op ANY/ALL`.
773+
774+**Row Types**
775+
776+Squeal 0.4 adds functions to define type expressions from tables and views
777+and a type expression for user defined types, `typetable`, `typeview` and
778+`typedef`.
779+
780+**Runtime Exceptions**
781+
782+Squeal now has an exception type which gives details on the sort of error
783+encountered and handler functions.
784+
785+```Haskell
786+data SquealException
787+ = PQException
788+ { sqlExecStatus :: LibPQ.ExecStatus
789+ , sqlStateCode :: Maybe ByteString
790+ -- ^ https://www.postgresql.org/docs/current/static/errcodes-appendix.html
791+ , sqlErrorMessage :: Maybe ByteString
792+ }
793+ | ResultException Text
794+ | ParseException Text
795+ deriving (Eq, Show)
796+instance Exception SquealException
797+
798+catchSqueal
799+ :: MonadBaseControl IO io
800+ => io a
801+ -> (SquealException -> io a) -- ^ handler
802+ -> io a
803+
804+handleSqueal
805+ :: MonadBaseControl IO io
806+ => (SquealException -> io a) -- ^ handler
807+ -> io a -> io a
808+```
809+
810+**Additional Changes**
811+
812+Squeal 0.4 adds `field` and `index` functions to get components of composite
813+and array expressions.
814+
815+Squeal 0.4 adds a dependency on `records-sop` to offload a lot of boilerplate
816+type family logic that was needed for `RowPG`.
817+
818+The above changes required major and minor changes to Squeal DSL functions.
819+Please consult the documentation.
820+
821+### Version 0.3.2 - August 4, 2018
822+
823+Version 0.3.2 features extensive support for `JSON` functionality with
824+more than 50 new functions.
825+This work is entirely due to [Mike Ledger](https://github.com/mikeplus64)
826+who has been making terrific contributions to Squeal. Thanks!
827+We also got some examples in the documentation for pools submitted by
828+[Raveline](https://github.com/Raveline). I'm so pleased to be
829+getting pull requests and issue submissions from you all!
830+
831+### Version 0.3.1 - July 7, 2018
832+
833+Version 0.3.1 of Squeal enables the "Scrap your Nils" trick for
834+heterogeneous lists of `Alias`es, `Aliased` expressions, `PGlabel`s and `By`s
835+with the typeclasses `IsLabel`, `IsQualified`, `IsPGlabel`,
836+and the new `Aliasable` typeclass, to eliminate all need of using `Nil` in a list.
837+There were a couple minor name changes, i.e. the function `group` was renamed to `groupBy`.
838+Please consult the documentation.
839+
840+### Version 0.3 - June 26, 2018
841+
842+Version 0.3 of Squeal adds views as well as composite and enumerated types to Squeal.
843+To support these features, a new kind `SchemumType` was added.
844+
845+```Haskell
846+data SchemumType
847+ = Table TableType
848+ | View RelationType
849+ | Typedef PGType
850+```
851+
852+As a consequence, you will have to update your schema definitions like so:
853+
854+```Haskell
855+-- Squeal 0.2
856+type Schema =
857+ '[ "users" :::
858+ '[ "pk_users" ::: 'PrimaryKey '["id"] ] :=>
859+ '[ "id" ::: 'Def :=> 'NotNull 'PGint4
860+ , "name" ::: 'NoDef :=> 'NotNull 'PGtext
861+ ]
862+ ]
863+
864+-- Squeal 0.3
865+type Schema =
866+ '[ "users" ::: 'Table (
867+ '[ "pk_users" ::: 'PrimaryKey '["id"] ] :=>
868+ '[ "id" ::: 'Def :=> 'NotNull 'PGint4
869+ , "name" ::: 'NoDef :=> 'NotNull 'PGtext
870+ ])
871+ ]
872+```
873+
874+**Views**
875+
876+You can now create, drop, and query views.
877+
878+```Haskell
879+>>> :{
880+type ABC =
881+ ('[] :: TableConstraints) :=>
882+ '[ "a" ::: 'NoDef :=> 'Null 'PGint4
883+ , "b" ::: 'NoDef :=> 'Null 'PGint4
884+ , "c" ::: 'NoDef :=> 'Null 'PGint4
885+ ]
886+type BC =
887+ '[ "b" ::: 'Null 'PGint4
888+ , "c" ::: 'Null 'PGint4
889+ ]
890+:}
891+
892+>>> :{
893+let
894+ definition :: Definition '["abc" ::: 'Table ABC ] '["abc" ::: 'Table ABC, "bc" ::: 'View BC]
895+ definition = createView #bc (select (#b :* #c :* Nil) (from (table #abc)))
896+in printSQL definition
897+:}
898+CREATE VIEW "bc" AS SELECT "b" AS "b", "c" AS "c" FROM "abc" AS "abc";
899+
900+>>> :{
901+let
902+ definition :: Definition '["abc" ::: 'Table ABC, "bc" ::: 'View BC] '["abc" ::: 'Table ABC]
903+ definition = dropView #bc
904+in printSQL definition
905+:}
906+DROP VIEW "bc";
907+
908+>>> :{
909+let
910+ query :: Query '["abc" ::: 'Table ABC, "bc" ::: 'View BC] '[] BC
911+ query = selectStar (from (view #bc))
912+in printSQL query
913+:}
914+SELECT * FROM "bc" AS "bc"
915+```
916+
917+**Enumerated Types**
918+
919+PostgreSQL has a powerful type system. It even allows for user defined types.
920+For instance, you can define enumerated types which are data types that comprise
921+a static, ordered set of values. They are equivalent to Haskell algebraic data
922+types whose constructors are nullary. An example of an enum type might be the days of the week,
923+or a set of status values for a piece of data.
924+
925+Enumerated types are created using the `createTypeEnum` command, for example:
926+
927+```Haskell
928+>>> :{
929+let
930+ definition :: Definition '[] '["mood" ::: 'Typedef ('PGenum '["sad", "ok", "happy"])]
931+ definition = createTypeEnum #mood (label @"sad" :* label @"ok" :* label @"happy" :* Nil)
932+:}
933+>>> printSQL definition
934+CREATE TYPE "mood" AS ENUM ('sad', 'ok', 'happy');
935+```
936+
937+Enumerated types can also be generated from a Haskell algebraic data type with nullary constructors, for example:
938+
939+```Haskell
940+>>> data Schwarma = Beef | Lamb | Chicken deriving GHC.Generic
941+>>> instance SOP.Generic Schwarma
942+>>> instance SOP.HasDatatypeInfo Schwarma
943+
944+>>> :kind! EnumFrom Schwarma
945+EnumFrom Schwarma :: PGType
946+= 'PGenum '["Beef", "Lamb", "Chicken"]
947+
948+>>> :{
949+let
950+ definition :: Definition '[] '["schwarma" ::: 'Typedef (EnumFrom Schwarma)]
951+ definition = createTypeEnumFrom @Schwarma #schwarma
952+:}
953+>>> printSQL definition
954+CREATE TYPE "schwarma" AS ENUM ('Beef', 'Lamb', 'Chicken');
955+```
956+
957+You can express values of an enum type using `label`, which is an overloaded method
958+of the `IsPGlabel` typeclass.
959+
960+```Haskell
961+>>> :{
962+let
963+ expression :: Expression sch rels grp params ('NotNull (EnumFrom Schwarma))
964+ expression = label @"Chicken"
965+in printSQL expression
966+:}
967+'Chicken'
968+```
969+
970+**Composite Types**
971+
972+In addition to enum types, you can define composite types.
973+A composite type represents the structure of a row or record;
974+it is essentially just a list of field names and their data types.
975+
976+
977+`createTypeComposite` creates a composite type. The composite type is
978+specified by a list of attribute names and data types.
979+
980+```Haskell
981+>>> :{
982+let
983+ definition :: Definition '[] '["complex" ::: 'Typedef ('PGcomposite '["real" ::: 'PGfloat8, "imaginary" ::: 'PGfloat8])]
984+ definition = createTypeComposite #complex (float8 `As` #real :* float8 `As` #imaginary :* Nil)
985+:}
986+>>> printSQL definition
987+CREATE TYPE "complex" AS ("real" float8, "imaginary" float8);
988+```
989+
990+Composite types are almost equivalent to Haskell record types.
991+However, because of the potential presence of `NULL`
992+all the record fields must be `Maybe`s of basic types.
993+Composite types can be generated from a Haskell record type, for example:
994+
995+```Haskell
996+>>> data Complex = Complex {real :: Maybe Double, imaginary :: Maybe Double} deriving GHC.Generic
997+>>> instance SOP.Generic Complex
998+>>> instance SOP.HasDatatypeInfo Complex
999+
1000+>>> :kind! CompositeFrom Complex
1001+CompositeFrom Complex :: PGType
1002+= 'PGcomposite '['("real", 'PGfloat8), '("imaginary", 'PGfloat8)]
1003+
1004+>>> :{
1005+let
1006+ definition :: Definition '[] '["complex" ::: 'Typedef (CompositeFrom Complex)]
1007+ definition = createTypeCompositeFrom @Complex #complex
1008+in printSQL definition
1009+:}
1010+CREATE TYPE "complex" AS ("real" float8, "imaginary" float8);
1011+```
1012+
1013+A row constructor is an expression that builds a row value
1014+(also called a composite value) using values for its member fields.
1015+
1016+```Haskell
1017+>>> :{
1018+let
1019+ i :: Expression '[] '[] 'Ungrouped '[] ('NotNull (CompositeFrom Complex))
1020+ i = row (0 `As` #real :* 1 `As` #imaginary :* Nil)
1021+:}
1022+>>> printSQL i
1023+ROW(0, 1)
1024+```
1025+
1026+You can also use `(&)` to apply a field label to a composite value.
1027+
1028+```Haskell
1029+>>> :{
1030+let
1031+ expr :: Expression '[] '[] 'Ungrouped '[] ('Null 'PGfloat8)
1032+ expr = i & #imaginary
1033+in printSQL expr
1034+:}
1035+(ROW(0, 1)).imaginary
1036+```
1037+
1038+Both composite and enum types can be automatically encoded from and decoded to their equivalent Haskell types.
1039+And they can be dropped.
1040+
1041+```Haskell
1042+>>> :{
1043+let
1044+ definition :: Definition '["mood" ::: 'Typedef ('PGenum '["sad", "ok", "happy"])] '[]
1045+ definition = dropType #mood
1046+:}
1047+>>> printSQL definition
1048+DROP TYPE "mood";
1049+```
1050+
1051+**Additional Changes**
1052+
1053+Squeal 0.3 also introduces a typeclass `HasAll` similar to `Has` but for a list of aliases.
1054+This makes it possible to clean up some unfortunately messy Squeal 0.2 definitions.
1055+
1056+```Haskell
1057+-- Squeal 0.2
1058+>>> unique (Column #a :* Column #b :* Nil)
1059+
1060+-- Squeal 0.3
1061+>>> unique (#a :* #b :* Nil)
1062+```
1063+
1064+Squeal 0.3 also adds `IsLabel` instances for `Aliased` expressions and tables as well as
1065+heterogeneous lists, allowing for some more economy of code.
1066+
1067+```Haskell
1068+-- Squeal 0.2 (or 0.3)
1069+>>> select (#a `As` #a :* Nil) (from (table (#t `As` #t)))
1070+
1071+-- Squeal 0.3
1072+>>> select #a (from (table #t))
1073+```
1074+
1075+Squeal 0.3 also fixes a bug that prevented joined queries on self-referencing tables.
1076+
1077+The above changes required major and minor changes to Squeal DSL functions.
1078+Please consult the documentation.
1079+
1080+### Version 0.2.1 - April 7, 2018
1081+
1082+This minor update fixes an issue where alias identifiers could conflict with
1083+reserved words in PostgreSQL. To fix the issue, alias identifiers are now
1084+quoted. Thanks to Petter Rasmussen for the fix.
1085+
1086+### Version 0.2 - March 26, 2018
1087+
1088+**Changes**
1089+- **Constraints** - Type level table constraints like primary and foreign keys and column constraints like having `DEFAULT`.
1090+- **Migrations** - Support for linear, invertible migrations tracked in an auxiliary table
1091+- **Arrays** - Support for fixed- and variable-length arrays
1092+- **Aliases** - Generalized `Has` constraint
1093+- **Pools** - Support for pooled connections
1094+- **Transactions** - Support for transaction control language
1095+- **Queries, Manipulations, Definitions** - Small and large changes to Squeal's DSL
1096+
1097+Well, a lot of things changed!
1098+
1099+**Constraints**
1100+
1101+An important request was to bring constraints to the type level.
1102+This means that more of the schema is statically known. In `0.1` column constraints - which boil down
1103+to having `DEFAULT` or not - were at the type level, but they were confusingly named.
1104+
1105+```haskell
1106+0.1: 'Optional ('NotNull 'PGInt4)
1107+0.2: 'Def :=> 'NotNull 'PGInt4
1108+0.1: 'Required ('NotNull 'PGInt4)
1109+0.2: 'NoDef :=> 'NotNull 'PGInt4
1110+```
1111+
1112+The `:=>` type operator is intended to helpfully connote a constraint relation.
1113+It's also used for table constraints which are new in `0.2`.
1114+
1115+```haskell
1116+"emails" :::
1117+ '[ "pk_emails" ::: 'PrimaryKey '["id"]
1118+ , "fk_user_id" ::: 'ForeignKey '["user_id"] "users" '["id"]
1119+ ] :=>
1120+ '[ "id" ::: 'Def :=> 'NotNull 'PGint4
1121+ , "user_id" ::: 'NoDef :=> 'NotNull 'PGint4
1122+ , "email" ::: 'NoDef :=> 'Null 'PGtext
1123+ ]
1124+```
1125+
1126+Another change in the constraint system was the removal of column constraints from
1127+query and manipulation results, as result columns don't support a notion of `DEFAULT`.
1128+This necessitates a distinction between `TableType`s which have both column and table
1129+constraints and `RelationType`s which have neither.
1130+
1131+**Migrations**
1132+
1133+Migrations are a hot topic and many people have requested this feature. Squeal `0.2`
1134+adds support for linear, invertible migrations. That is, a migration is a named,
1135+invertible, schema-tracking computation:
1136+
1137+```haskell
1138+data Migration io schema0 schema1 = Migration
1139+ { name :: Text -- ^ The `name` of a `Migration`.
1140+ -- Each `name` in a `Migration` should be unique.
1141+ , up :: PQ schema0 schema1 io () -- ^ The `up` instruction of a `Migration`.
1142+ , down :: PQ schema1 schema0 io () -- ^ The `down` instruction of a `Migration`.
1143+ }
1144+```
1145+
1146+And, `Migration`s can be put together in an "aligned" list:
1147+
1148+```haskell
1149+data AlignedList p x0 x1 where
1150+ Done :: AlignedList p x x
1151+ (:>>) :: p x0 x1 -> AlignedList p x1 x2 -> AlignedList p x0 x2
1152+```
1153+
1154+These aligned lists are free categories and might look familiar from
1155+the [reflections without remorse](http://okmij.org/ftp/Haskell/zseq.pdf) technique,
1156+which uses their cousins, aligned sequences.
1157+
1158+In the context of migration, they allow one to chain new migrations as a
1159+schema evolves over time. `Migration`s' execution is tracked in an auxiliary
1160+migrations table. Migration lists can then be run or rewinded.
1161+
1162+```haskell
1163+migrateUp
1164+ :: MonadBaseControl IO io
1165+ => AlignedList (Migration io) schema0 schema1 -- ^ migrations to run
1166+ -> PQ
1167+ ("schema_migrations" ::: MigrationsTable ': schema0)
1168+ ("schema_migrations" ::: MigrationsTable ': schema1)
1169+ io ()
1170+
1171+migrateDown
1172+ :: MonadBaseControl IO io
1173+ => AlignedList (Migration io) schema0 schema1 -- ^ migrations to rewind
1174+ -> PQ
1175+ ("schema_migrations" ::: MigrationsTable ': schema1)
1176+ ("schema_migrations" ::: MigrationsTable ': schema0)
1177+ io ()
1178+```
1179+
1180+**Aliases**
1181+
1182+In Squeal `0.1`, we had different typeclasses `HasColumn` and `HasTable` to indicate
1183+that a table has a column or that a schema has a table. In Squeal `0.2` this has been
1184+unified to a single typeclass,
1185+
1186+```haskell
1187+class KnownSymbol alias =>
1188+ Has (alias :: Symbol) (fields :: [(Symbol,kind)]) (field :: kind)
1189+ | alias fields -> field where
1190+```
1191+
1192+**Arrays**
1193+
1194+Support for array types has been added to Squeal `0.2` through
1195+the `'PGfixarray` and `'PGvararray` `PGType`s. Array values can be
1196+constructed using the `array` function and can be encoded from and decoded to
1197+Haskell `Vector`s.
1198+
1199+**Pools**
1200+
1201+Squeal `0.2` provides a monad transformer `PoolPQ` that's an instance of `MonadPQ`.
1202+The `resource-pool` library is leveraged to provide striped pools of `Connection`s.
1203+`PoolPQ` should be a drop in replacement for running `Manipulation`s and `Query`s with
1204+`PQ`.
1205+
1206+**Transactions**
1207+
1208+Squeal `0.2` supports a simple transaction control language. A computation in
1209+`MonadPQ` can be called `transactionally` with different levels of isolation.
1210+Additionally, a schema changing computation, a data definition, can be run in a
1211+transaction. Running a computation in a transaction means that all SQL statements
1212+will be rolled back if an exception is encountered.
1213+
1214+**Queries, Manipulations and Definitions**
1215+
1216+The above changes required major and minor changes to Squeal DSL functions.
1217+Please consult the documentation.
circle.ymldeleted−12
@@ -1,12 +0,0 @@
1−dependencies:
2− cache_directories:
3− - "~/.stack"
4− - ".stack-work"
5− override:
6− - stack upgrade
7− - stack update
8− - stack setup
9− - stack test --no-run-tests
10−test:
11− override:
12− - stack test
scrap-your-nils.mdnew file+60
@@ -0,0 +1,60 @@
1+## Scrap your Nils
2+
3+One of the most useful types I've come across in Haskell is the type of
4+"heterogeneous lists". This is the same as the [Rec](http://hackage.haskell.org/package/vinyl-0.8.1.1/docs/Data-Vinyl-Core.html)
5+datatype from the [vinyl](http://hackage.haskell.org/package/vinyl) library.
6+It's also the same as the [NP](http://hackage.haskell.org/package/generics-sop-0.3.2.0/docs/Generics-SOP-NP.html)
7+datatype from the [generics-sop](http://hackage.haskell.org/package/generics-sop) library.
8+Squeal makes heavy use of this type.
9+
10+```Haskell
11+>>> import Generics.SOP (NP(..))
12+>>> :i NP
13+type role NP representational nominal
14+data NP (a :: k -> *) (b :: [k]) where
15+ Nil :: forall k (a :: k -> *). NP a '[]
16+ (:*) :: forall k (a :: k -> *) (x :: k) (xs :: [k]).
17+ (a x) -> (NP a xs) -> NP a (x : xs)
18+ -- Defined in ‘Generics.SOP.NP’
19+```
20+
21+This type allows us to construct "product" types, where the types of the individual
22+"terms" are hosted at the type level.
23+
24+```Haskell
25+>>> :set -XDataKinds
26+>>> import Generics.SOP (I(..))
27+>>> let example = I "foo" :* I pi :* Nil :: NP I '[String, Double]
28+>>> example
29+I "foo" :* I 3.141592653589793 :* Nil
30+```
31+
32+One thing Squeal uses `NP` for is to form lists of aliases,
33+using GHC's `OverloadedLabels` extension, hosting the names
34+of the aliases themselves at the type level.
35+
36+```Haskell
37+>>> :set -XKindSignatures -XOverloadedLabels -XFlexibleInstances -XMultiParamTypeClasses
38+>>> import GHC.TypeLits
39+>>> import GHC.OverloadedLabels
40+>>> data Alias (alias :: Symbol) = Alias deriving (Eq,Ord,Show)
41+>>> instance IsLabel label (Alias label) where fromLabel = Alias
42+>>> let aliases = #foo :* #bar :* Nil :: NP Alias '["foo", "bar"]
43+```
44+
45+However, it's very ugly to have to end every list with `:* Nil`.
46+When I announced the release of Squeal, people rightly [complained](https://www.reddit.com/r/haskell/comments/6yr5v6/announcing_squeal_a_deep_embedding_of_sql_in/dmq8vvn)
47+about the syntactic noise. Luckily, there's a neat trick we can use to get rid of it.
48+Making an `IsLabel` instance not only for elements of our list
49+but also for lists of length 1, we can ask GHC to interpret
50+the last label as a list.
51+
52+```Haskell
53+>>> instance IsLabel label (NP Alias '[label]) where fromLabel = Alias :* Nil
54+>>> let aliases' = #foo :* #bar :: NP Alias '["foo", "bar"]
55+```
56+
57+Version 0.3.1 of Squeal enables the "Scrap your Nils" trick for
58+heterogeneous lists of `Alias`es, `Aliased` expressions, `PGlabel`s and `By`s
59+with the typeclasses `IsLabel`, `IsQualified`, `IsPGlabel`,
60+and the new `Aliasable` typeclass, to eliminate all need of using `Nil` in a list.
squeal-postgresql/README.md+2−155
@@ -1,164 +1,11 @@
1−# squeal
1+# squeal-postgresql
22
33![squeal-icon](http://www.emoticonswallpapers.com/emotion/cute-big-pig/cute-pig-smiley-046.gif)
44
5−[![CircleCI](https://circleci.com/gh/echatav/squeal.svg?style=svg&circle-token=a699a654ef50db2c3744fb039cf2087c484d1226)](https://circleci.com/gh/echatav/squeal)
5+[![CircleCI](https://circleci.com/gh/echatav/squeal.svg?style=svg&circle-token=a699a654ef50db2c3744fb039cf2087c484d1226)](https://circleci.com/gh/morphismtech/squeal)
66
77[Github](https://github.com/morphismtech/squeal)
88
99[Hackage](https://hackage.haskell.org/package/squeal-postgresql)
1010
1111[Stackage](https://www.stackage.org/package/squeal-postgresql)
12−
13−## installation
14−
15−`stack install squeal-postgresql`
16−
17−## usage
18−
19−Squeal is a deep embedding of PostgreSQL in Haskell. Let's see an example!
20−
21−First, we need some language extensions because Squeal uses modern GHC features.
22−
23−```haskell
24−{-# LANGUAGE
25− DataKinds
26− , DeriveGeneric
27− , OverloadedLabels
28− , OverloadedStrings
29− , TypeApplications
30− , TypeOperators
31−#-}
32−```
33−
34−Here comes the Main module and imports.
35−
36−```haskell
37−module Main (main) where
38−
39−import Control.Monad.Base (liftBase)
40−import Data.Int (Int32)
41−import Data.Text (Text)
42−
43−import Squeal.PostgreSQL
44−```
45−
46−We'll use generics to easily convert between Haskell and PostgreSQL values.
47−
48−```haskell
49−import qualified Generics.SOP as SOP
50−import qualified GHC.Generics as GHC
51−```
52−
53−The first step is to define the schema of our database. This is where we use DataKinds and TypeOperators. The schema consists of a type-level list of tables, a `:::` pairing of a type level string or `Symbol` and a list a columns, itself a `:::` pairing of a `Symbol` and a `ColumnType`. The `ColumnType` describes the PostgreSQL type of the column as well as whether or not it may contain `NULL` and whether or not inserts and updates can use a `DEFAULT`. For our schema, we'll define two tables, a users table and an emails table.
54−
55−```haskell
56−type Schema =
57− '[ "users" :::
58− '[ "id" ::: 'Optional ('NotNull 'PGint4)
59− , "name" ::: 'Required ('NotNull 'PGtext)
60− ]
61− , "emails" :::
62− '[ "id" ::: 'Optional ('NotNull 'PGint4)
63− , "user_id" ::: 'Required ('NotNull 'PGint4)
64− , "email" ::: 'Required ('Null 'PGtext)
65− ]
66− ]
67−```
68−
69−Next, we'll write Definitions to set up and tear down the schema. In Squeal, a Definition is a `createTable`, `alterTable` or `dropTable` command and has two type parameters, corresponding to the schema before being run and the schema after. We can compose definitions using `>>>`. Here and in the rest of our commands we make use of overloaded labels to refer to named tables and columns in our schema.
70−
71−```haskell
72−setup :: Definition '[] Schema
73−setup =
74− createTable #users
75− ( serial `As` #id :*
76− (text & notNull) `As` #name :* Nil )
77− [ primaryKey (Column #id :* Nil) ]
78− >>>
79− createTable #emails
80− ( serial `As` #id :*
81− (int & notNull) `As` #user_id :*
82− text `As` #email :* Nil )
83− [ primaryKey (Column #id :* Nil)
84− , foreignKey (Column #user_id :* Nil) #users (Column #id :* Nil)
85− OnDeleteCascade OnUpdateCascade ]
86−```
87−
88−Notice that setup starts with an empty schema `'[]` and produces `Schema`. In our `createTable` commands we included `TableConstraint`s to define primary and foreign keys, making them somewhat complex. Our tear down `Definition` is simpler.
89−
90−```haskell
91−teardown :: Definition Schema '[]
92−teardown = dropTable #emails >>> dropTable #users
93−```
94−
95−Next, we'll write `Manipulation`s to insert data into our two tables. A `Manipulation` is an `insertInto`, `update` or `deleteFrom` command and has three type parameters, the schema it refers to, a list of parameters it can take as input, and a list of columns it produces as output. When we insert into the users table, we will need a parameter for the name field but not for the id field. Since it's optional, we can use a default value. However, since the emails table refers to the users table, we will need to retrieve the user id that the insert generates and insert it into the emails table. Take a careful look at the type and definition of both of our inserts.
96−
97−```haskell
98−insertUser :: Manipulation Schema
99− '[ 'Required ('NotNull 'PGtext)]
100− '[ "fromOnly" ::: 'Required ('NotNull 'PGint4) ]
101−insertUser = insertInto #users
102− ( Values (def `As` #id :* param @1 `As` #name :* Nil) [] )
103− OnConflictDoNothing (Returning (#id `As` #fromOnly :* Nil))
104−
105−insertEmail :: Manipulation Schema
106− '[ 'Required ('NotNull 'PGint4), 'Required ('Null 'PGtext)] '[]
107−insertEmail = insertInto #emails ( Values
108− ( def `As` #id :*
109− param @1 `As` #user_id :*
110− param @2 `As` #email :* Nil) [] )
111− OnConflictDoNothing (Returning Nil)
112−```
113−
114−Next we write a `Query` to retrieve users from the database. We're not interested in the ids here, just the usernames and email addresses. We need to use an inner join to get the right result. A `Query` is like a `Manipulation` with the same kind of type parameters.
115−
116−```haskell
117−getUsers :: Query Schema '[]
118− '[ "userName" ::: 'Required ('NotNull 'PGtext)
119− , "userEmail" ::: 'Required ('Null 'PGtext) ]
120−getUsers = select
121− (#u ! #name `As` #userName :* #e ! #email `As` #userEmail :* Nil)
122− ( from (Table (#users `As` #u)
123− & InnerJoin (Table (#emails `As` #e))
124− (#u ! #id .== #e ! #user_id)) )
125−```
126−
127−Now that we've defined the SQL side of things, we'll need a Haskell type for users. We give the type `Generic` and `HasDatatypeInfo` instances so that we can decode the rows we receive when we run getUsers. Notice that the record fields of the `User` type match the column names of `getUsers`.
128−
129−```haskell
130−data User = User { userName :: Text, userEmail :: Maybe Text }
131− deriving (Show, GHC.Generic)
132−instance SOP.Generic User
133−instance SOP.HasDatatypeInfo User
134−```
135−
136−Let's also create some users to add to the database.
137−
138−```haskell
139−users :: [User]
140−users =
141− [ User "Alice" (Just "alice@gmail.com")
142− , User "Bob" Nothing
143− , User "Carole" (Just "carole@hotmail.com")
144− ]
145−```
146−
147−Now we can put together all the pieces into a program. The program connects to the database, sets up the schema, inserts the user data (using prepared statements as an optimization), queries the user data and prints it out and finally closes the connection. We can thread the changing schema information through by using the indexed `PQ` monad transformer and when the schema doesn't change we can use `Monad` and `MonadPQ` functionality.
148−
149−```haskell
150−main :: IO ()
151−main = void $
152− withConnection "host=localhost port=5432 dbname=exampledb" . runPQ $
153− define setup
154− & pqThen session
155− & thenDefine teardown
156− where
157− session = do
158− idResults <- traversePrepared insertUser (Only . userName <$> users)
159− ids <- traverse (fmap fromOnly . getRow (RowNumber 0)) idResults
160− traversePrepared_ insertEmail (zip (ids :: [Int32]) (userEmail <$> users))
161− usersResult <- runQuery getUsers
162− usersRows <- getRows usersResult
163− liftBase $ print (usersRows :: [User])
164−```
squeal-postgresql/exe/Example.hs+60−59
@@ -4,18 +4,18 @@
44 , FlexibleContexts
55 , OverloadedLabels
66 , OverloadedStrings
7− , PolyKinds
7+ , OverloadedLists
88 , TypeApplications
99 , TypeOperators
1010#-}
1111
1212module Main (main, main2) where
1313
14−import Control.Monad (void)
15−import Control.Monad.Base (liftBase, MonadBase)
16−import Data.Int (Int32)
14+import Control.Monad.IO.Class (MonadIO (..))
15+import Data.Int (Int16, Int32)
1716import Data.Monoid ((<>))
1817import Data.Text (Text)
18+import Data.Vector (Vector)
1919
2020import Squeal.PostgreSQL
2121
@@ -24,83 +24,84 @@ import qualified Generics.SOP as SOP
2424import qualified GHC.Generics as GHC
2525
2626type Schema =
27− '[ "users" :::
28− '[ "pk_id" ::: 'PrimaryKey '["id"] ] :=>
27+ '[ "users" ::: 'Table (
28+ '[ "pk_users" ::: 'PrimaryKey '["id"] ] :=>
2929 '[ "id" ::: 'Def :=> 'NotNull 'PGint4
3030 , "name" ::: 'NoDef :=> 'NotNull 'PGtext
31− ]
32− , "emails" :::
33− '[ "pk_id" ::: 'PrimaryKey '["id"]
31+ , "vec" ::: 'NoDef :=> 'NotNull ('PGvararray ('Null 'PGint2))
32+ ])
33+ , "emails" ::: 'Table (
34+ '[ "pk_emails" ::: 'PrimaryKey '["id"]
3435 , "fk_user_id" ::: 'ForeignKey '["user_id"] "users" '["id"]
3536 ] :=>
3637 '[ "id" ::: 'Def :=> 'NotNull 'PGint4
3738 , "user_id" ::: 'NoDef :=> 'NotNull 'PGint4
3839 , "email" ::: 'NoDef :=> 'Null 'PGtext
39− ]
40+ ])
41+ , "positive" ::: 'Typedef 'PGfloat4
4042 ]
4143
42−setup :: Definition '[] Schema
43−setup =
44+type Schemas = Public Schema
45+
46+setup :: Definition (Public '[]) Schemas
47+setup =
4448 createTable #users
45− ( #id serial :*
46− #name (text & notNull) :* Nil )
47− ( primaryKey (Column #id :* Nil) `As` #pk_id :* Nil )
49+ ( serial `as` #id :*
50+ (text & notNullable) `as` #name :*
51+ (vararray int2 & notNullable) `as` #vec )
52+ ( primaryKey #id `as` #pk_users )
4853 >>>
4954 createTable #emails
50− ( #id serial :*
51− #user_id (int & notNull) :*
52− #email text :* Nil )
53− ( primaryKey (Column #id :* Nil) `As` #pk_id :*
54− foreignKey (Column #user_id :* Nil) #users (Column #id :* Nil)
55− OnDeleteCascade OnUpdateCascade `As` #fk_user_id :* Nil )
56−
57−teardown :: Definition Schema '[]
58−teardown = dropTable #emails >>> dropTable #users
59−
60−insertUser :: Manipulation Schema '[ 'NotNull 'PGtext]
61− '[ "fromOnly" ::: 'NotNull 'PGint4 ]
62−insertUser = insertRows #users
63− (Default `As` #id :* Set (param @1) `As` #name :* Nil) []
64− OnConflictDoNothing (Returning (#id `As` #fromOnly :* Nil))
65−
66−insertEmail :: Manipulation Schema '[ 'NotNull 'PGint4, 'Null 'PGtext] '[]
67−insertEmail = insertRows #emails
68− ( Default `As` #id :*
69− Set (param @1) `As` #user_id :*
70− Set (param @2) `As` #email :* Nil ) []
71− OnConflictDoNothing (Returning Nil)
72−
73−getUsers :: Query Schema '[]
74− '[ "userName" ::: 'NotNull 'PGtext
75− , "userEmail" ::: 'Null 'PGtext ]
76−getUsers = select
77− (#u ! #name `As` #userName :* #e ! #email `As` #userEmail :* Nil)
78− ( from (Table (#users `As` #u)
79− & InnerJoin (Table (#emails `As` #e))
55+ ( serial `as` #id :*
56+ hask @Int32 `as` #user_id :*
57+ hask @(Maybe Text) `as` #email )
58+ ( primaryKey #id `as` #pk_emails :*
59+ foreignKey #user_id #users #id
60+ OnDeleteCascade OnUpdateCascade `as` #fk_user_id )
61+ >>>
62+ createDomain #positive real (#value .> 0 .&& (#value & isNotNull))
63+
64+teardown :: Definition Schemas (Public '[])
65+teardown = dropType #positive >>> dropTable #emails >>> dropTable #users
66+
67+insertUser :: Manipulation_ Schemas (Text, VarArray (Vector (Maybe Int16))) (Only Int32)
68+insertUser = insertInto #users
69+ (Values_ (Default `as` #id :* Set (param @1) `as` #name :* Set (param @2) `as` #vec))
70+ (OnConflict (OnConstraint #pk_users) DoNothing) (Returning_ (#id `as` #fromOnly))
71+
72+insertEmail :: Manipulation_ Schemas (Int32, Maybe Text) ()
73+insertEmail = insertInto_ #emails
74+ (Values_ (Default `as` #id :* Set (param @1) `as` #user_id :* Set (param @2) `as` #email))
75+
76+getUsers :: Query_ Schemas () User
77+getUsers = select_
78+ (#u ! #name `as` #userName :* #e ! #email `as` #userEmail :* #u ! #vec `as` #userVec)
79+ ( from (table (#users `as` #u)
80+ & innerJoin (table (#emails `as` #e))
8081 (#u ! #id .== #e ! #user_id)) )
8182
82−data User = User { userName :: Text, userEmail :: Maybe Text }
83+data User = User { userName :: Text, userEmail :: Maybe Text, userVec :: VarArray (Vector (Maybe Int16)) }
8384 deriving (Show, GHC.Generic)
8485instance SOP.Generic User
8586instance SOP.HasDatatypeInfo User
8687
8788users :: [User]
88−users =
89− [ User "Alice" (Just "alice@gmail.com")
90− , User "Bob" Nothing
91− , User "Carole" (Just "carole@hotmail.com")
89+users =
90+ [ User "Alice" (Just "alice@gmail.com") (VarArray [Nothing, Just 1])
91+ , User "Bob" Nothing (VarArray [Just 2, Nothing])
92+ , User "Carole" (Just "carole@hotmail.com") (VarArray [Just 3])
9293 ]
9394
94−session :: (MonadBase IO pq, MonadPQ Schema pq) => pq ()
95+session :: (MonadIO pq, MonadPQ Schemas pq) => pq ()
9596session = do
96− liftBase $ Char8.putStrLn "manipulating"
97− idResults <- traversePrepared insertUser (Only . userName <$> users)
98− ids <- traverse (fmap fromOnly . getRow (RowNumber 0)) idResults
97+ liftIO $ Char8.putStrLn "manipulating"
98+ idResults <- traversePrepared insertUser ([(userName user, userVec user) | user <- users])
99+ ids <- traverse (fmap fromOnly . getRow 0) idResults
99100 traversePrepared_ insertEmail (zip (ids :: [Int32]) (userEmail <$> users))
100− liftBase $ Char8.putStrLn "querying"
101+ liftIO $ Char8.putStrLn "querying"
101102 usersResult <- runQuery getUsers
102103 usersRows <- getRows usersResult
103− liftBase $ print (usersRows :: [User])
104+ liftIO $ print (usersRows :: [User])
104105
105106main :: IO ()
106107main = do
@@ -117,8 +118,8 @@ main = do
117118 finish connection3
118119
119120main2 :: IO ()
120−main2 = void $
121− withConnection "host=localhost port=5432 dbname=exampledb" . runPQ $
121+main2 =
122+ withConnection "host=localhost port=5432 dbname=exampledb" $
122123 define setup
123124 & pqThen session
124− & thenDefine teardown
125+ & pqThen (define teardown)
squeal-postgresql/squeal-postgresql.cabal+102−32
@@ -1,5 +1,5 @@
11name: squeal-postgresql
2−version: 0.1.1.4
2+version: 0.5.1.0
33synopsis: Squeal PostgreSQL Library
44description: Squeal is a type-safe embedding of PostgreSQL in Haskell
55homepage: https://github.com/morphismtech/squeal
@@ -22,56 +22,126 @@ library
2222 hs-source-dirs: src
2323 exposed-modules:
2424 Squeal.PostgreSQL
25+ Squeal.PostgreSQL.Alias
2526 Squeal.PostgreSQL.Binary
2627 Squeal.PostgreSQL.Definition
28+ Squeal.PostgreSQL.Definition.Function
29+ Squeal.PostgreSQL.Definition.Index
30+ Squeal.PostgreSQL.Definition.Table
31+ Squeal.PostgreSQL.Definition.Table.Constraint
32+ Squeal.PostgreSQL.Definition.Type
33+ Squeal.PostgreSQL.Definition.Schema
34+ Squeal.PostgreSQL.Definition.View
2735 Squeal.PostgreSQL.Expression
36+ Squeal.PostgreSQL.Expression.Aggregate
37+ Squeal.PostgreSQL.Expression.Collection
38+ Squeal.PostgreSQL.Expression.Comparison
39+ Squeal.PostgreSQL.Expression.Json
40+ Squeal.PostgreSQL.Expression.Literal
41+ Squeal.PostgreSQL.Expression.Logic
42+ Squeal.PostgreSQL.Expression.Math
43+ Squeal.PostgreSQL.Expression.Null
44+ Squeal.PostgreSQL.Expression.Parameter
45+ Squeal.PostgreSQL.Expression.Range
46+ Squeal.PostgreSQL.Expression.Set
47+ Squeal.PostgreSQL.Expression.Sort
48+ Squeal.PostgreSQL.Expression.Subquery
49+ Squeal.PostgreSQL.Expression.Text
50+ Squeal.PostgreSQL.Expression.TextSearch
51+ Squeal.PostgreSQL.Expression.Time
52+ Squeal.PostgreSQL.Expression.Type
53+ Squeal.PostgreSQL.Expression.Window
54+ Squeal.PostgreSQL.List
2855 Squeal.PostgreSQL.Manipulation
56+ Squeal.PostgreSQL.Migration
57+ Squeal.PostgreSQL.Pool
58+ Squeal.PostgreSQL.PG
2959 Squeal.PostgreSQL.PQ
30− Squeal.PostgreSQL.Prettyprint
60+ Squeal.PostgreSQL.Render
3161 Squeal.PostgreSQL.Query
3262 Squeal.PostgreSQL.Schema
63+ Squeal.PostgreSQL.Transaction
3364 default-language: Haskell2010
34− ghc-options: -Wall -fprint-explicit-kinds
65+ ghc-options: -Wall
66+ build-depends:
67+ aeson >= 1.2.4.0
68+ , base >= 4.11.1.0 && < 5.0
69+ , binary-parser >= 0.5.5
70+ , bytestring >= 0.10.8.2
71+ , bytestring-strict-builder >= 0.4.5
72+ , deepseq >= 1.4.3.0
73+ , free-categories >= 0.1.0.0
74+ , generics-sop >= 0.3.2.0 && < 0.5.0.0
75+ , mmorph >= 1.1.1
76+ , mtl >= 2.2.2
77+ , network-ip >= 0.3.0.2
78+ , postgresql-binary >= 0.12.1
79+ , postgresql-libpq >= 0.9.4.1
80+ , records-sop >= 0.1.0.0
81+ , resource-pool >= 0.2.3.2
82+ , scientific >= 0.3.5.3
83+ , text >= 1.2.3.0
84+ , time >= 1.8.0.2
85+ , transformers >= 0.5.2.0
86+ , unliftio >= 0.2.10
87+ , unliftio-pool >= 0.2.1.0
88+ , uuid-types >= 1.0.3
89+ , vector >= 0.12.0.1
90+
91+test-suite doctest
92+ default-language: Haskell2010
93+ type: exitcode-stdio-1.0
94+ hs-source-dirs: test
95+ ghc-options: -Wall
96+ main-is: Doc.hs
97+ build-depends:
98+ base >= 4.10.0.0
99+ , doctest >= 0.11.4
100+ , squeal-postgresql
101+
102+test-suite properties
103+ default-language: Haskell2010
104+ type: exitcode-stdio-1.0
105+ hs-source-dirs: test
106+ ghc-options: -Wall
107+ main-is: Property.hs
35108 build-depends:
36− aeson >= 1.2.1.0 && < 2
37− , base >= 4.10.0.0 && < 5
38− , bytestring >= 0.10.8.2 && < 1
39− , deepseq >= 1.4.3.0 && < 2
40− , generics-sop >= 0.3.1.0 && < 1
41− , lifted-base >= 0.2.3.11 && < 1
42− , monad-control >= 1.0.2.2 && < 2
43− , mtl >= 2.2.1 && < 3
44− , network-ip >= 0.3.0.2 && < 1
45− , postgresql-binary >= 0.12.1 && < 1
46− , postgresql-libpq >= 0.9.3.1 && < 1
47− , scientific >= 0.3.5.1 && < 1
48− , text >= 1.2.2.2 && < 2
49− , time >= 1.8.0.2 && < 2
50− , transformers >= 0.5.2.0 && < 1
51− , transformers-base >= 0.4.4 && < 1
52− , uuid >= 1.3.13 && < 2
109+ base >= 4.10.0.0
110+ , bytestring >= 0.10.8.2
111+ , hedgehog >= 1.0
112+ , mtl >= 2.2.2
113+ , scientific >= 0.3.5.3
114+ , squeal-postgresql
115+ , time >= 1.8.0.2
53116
54−test-suite squeal-postgresql-doctest
117+test-suite spec
55118 default-language: Haskell2010
56119 type: exitcode-stdio-1.0
57120 hs-source-dirs: test
58121 ghc-options: -Wall
59− main-is: DocTest.hs
122+ main-is: Spec.hs
60123 build-depends:
61− base >= 4.10.0.0 && < 5
62− , doctest >= 0.11.4 && < 1
124+ base >= 4.10.0.0
125+ , async >= 2.2.2
126+ , bytestring >= 0.10.8.2
127+ , generics-sop >= 0.3.1.0
128+ , hspec >= 2.4.8
129+ , mtl >= 2.2.2
130+ , squeal-postgresql
131+ , text >= 1.2.2.2
132+ , vector >= 0.12.0.1
63133
64−executable squeal-postgresql-example
134+executable example
65135 default-language: Haskell2010
66136 hs-source-dirs: exe
67137 ghc-options: -Wall
68138 main-is: Example.hs
69139 build-depends:
70− base >= 4.10.0.0 && < 5
71− , bytestring >= 0.10.8.2 && < 1
72− , generics-sop >= 0.3.1.0 && < 1
73− , mtl >= 2.2.1 && < 3
140+ base >= 4.10.0.0 && < 5.0
141+ , bytestring >= 0.10.8.2
142+ , generics-sop >= 0.3.1.0
143+ , mtl >= 2.2.1
74144 , squeal-postgresql
75− , text >= 1.2.2.2 && < 2
76− , transformers >= 0.5.2.0 && < 1
77− , transformers-base >= 0.4.4 && < 1
145+ , text >= 1.2.2.2
146+ , transformers >= 0.5.2.0
147+ , vector >= 0.12.0.1
squeal-postgresql/src/Squeal/PostgreSQL.hs+233−186
@@ -1,186 +1,233 @@
1−-- | Module: Squeal.PostgreSQL
2−-- Description: Squeel export module
3−-- Copyright: (c) Eitan Chatav, 2017
4−-- Maintainer: eitan@morphism.tech
5−-- Stability: experimental
6−--
7−-- Squeal is a deep embedding of PostgreSQL in Haskell. Let's see an example!
8−--
9−-- First, we need some language extensions because Squeal uses modern GHC
10−-- features.
11−--
12−-- > {-# LANGUAGE
13−-- > DataKinds
14−-- > , DeriveGeneric
15−-- > , OverloadedLabels
16−-- > , OverloadedStrings
17−-- > , TypeApplications
18−-- > , TypeOperators
19−-- > #-}
20−--
21−-- Here comes the @Main@ module and imports.
22−--
23−-- > module Main (main) where
24−-- >
25−-- > import Control.Monad.Base (liftBase)
26−-- > import Data.Int (Int32)
27−-- > import Data.Text (Text)
28−-- >
29−-- > import Squeal.PostgreSQL
30−--
31−-- We'll use generics to easily convert between Haskell and PostgreSQL values.
32−--
33−-- > import qualified Generics.SOP as SOP
34−-- > import qualified GHC.Generics as GHC
35−--
36−-- The first step is to define the schema of our database. This is where
37−-- we use @DataKinds@ and @TypeOperators@. The schema consists of a type-level
38−-- list of tables, a `:::` pairing of a type level string or
39−-- @Symbol@ and a list a columns, itself a `:::` pairing of a
40−-- @Symbol@ and a `ColumnType`. The `ColumnType` describes the
41−-- PostgreSQL type of the column as well as whether or not it may contain
42−-- @NULL@ and whether or not inserts and updates can use a @DEFAULT@. For our
43−-- schema, we'll define two tables, a users table and an emails table.
44−--
45−-- > type Schema =
46−-- > '[ "users" :::
47−-- > '[ "id" ::: 'Optional ('NotNull 'PGint4)
48−-- > , "name" ::: 'Required ('NotNull 'PGtext)
49−-- > ]
50−-- > , "emails" :::
51−-- > '[ "id" ::: 'Optional ('NotNull 'PGint4)
52−-- > , "user_id" ::: 'Required ('NotNull 'PGint4)
53−-- > , "email" ::: 'Required ('Null 'PGtext)
54−-- > ]
55−-- > ]
56−--
57−-- Next, we'll write `Definition`s to set up and tear down the schema. In
58−-- Squeal, a `Definition` is a `createTable`, `alterTable` or `dropTable`
59−-- command and has two type parameters, corresponding to the schema
60−-- before being run and the schema after. We can compose definitions using
61−-- `>>>`. Here and in the rest of our commands we make use of overloaded
62−-- labels to refer to named tables and columns in our schema.
63−--
64−-- > setup :: Definition '[] Schema
65−-- > setup =
66−-- > createTable #users
67−-- > ( serial `As` #id :*
68−-- > (text & notNull) `As` #name :* Nil )
69−-- > [ primaryKey (Column #id :* Nil) ]
70−-- > >>>
71−-- > createTable #emails
72−-- > ( serial `As` #id :*
73−-- > (int & notNull) `As` #user_id :*
74−-- > text `As` #email :* Nil )
75−-- > [ primaryKey (Column #id :* Nil)
76−-- > , foreignKey (Column #user_id :* Nil) #users (Column #id :* Nil)
77−-- > OnDeleteCascade OnUpdateCascade ]
78−--
79−-- Notice that @setup@ starts with an empty schema @'[]@ and produces @Schema@.
80−-- In our `createTable` commands we included `TableConstraint`s to define
81−-- primary and foreign keys, making them somewhat complex. Our tear down
82−-- `Definition` is simpler.
83−--
84−-- > teardown :: Definition Schema '[]
85−-- > teardown = dropTable #emails >>> dropTable #users
86−--
87−-- Next, we'll write `Manipulation`s to insert data into our two tables.
88−-- A `Manipulation` is a `insertInto`, `update` or `deleteFrom` command and
89−-- has three type parameters, the schema it refers to, a list of parameters
90−-- it can take as input, and a list of columns it produces as output. When
91−-- we insert into the users table, we will need a parameter for the @name@
92−-- field but not for the @id@ field. Since it's optional, we can use a default
93−-- value. However, since the emails table refers to the users table, we will
94−-- need to retrieve the user id that the insert generates and insert it into
95−-- the emails table. Take a careful look at the type and definition of both
96−-- of our inserts.
97−--
98−-- > insertUser :: Manipulation Schema
99−-- > '[ 'Required ('NotNull 'PGtext)]
100−-- > '[ "fromOnly" ::: 'Required ('NotNull 'PGint4) ]
101−-- > insertUser = insertInto #users
102−-- > ( Values (def `As` #id :* param @1 `As` #name :* Nil) [] )
103−-- > OnConflictDoNothing (Returning (#id `As` #fromOnly :* Nil))
104−-- >
105−-- > insertEmail :: Manipulation Schema
106−-- > '[ 'Required ('NotNull 'PGint4), 'Required ('Null 'PGtext)] '[]
107−-- > insertEmail = insertInto #emails ( Values
108−-- > ( def `As` #id :*
109−-- > param @1 `As` #user_id :*
110−-- > param @2 `As` #email :* Nil) [] )
111−-- > OnConflictDoNothing (Returning Nil)
112−--
113−-- Next we write a `Query` to retrieve users from the database. We're not
114−-- interested in the ids here, just the usernames and email addresses. We
115−-- need to use an inner join to get the right result. A `Query` is like a
116−-- `Manipulation` with the same kind of type parameters.
117−--
118−-- > getUsers :: Query Schema '[]
119−-- > '[ "userName" ::: 'Required ('NotNull 'PGtext)
120−-- > , "userEmail" ::: 'Required ('Null 'PGtext) ]
121−-- > getUsers = select
122−-- > (#u ! #name `As` #userName :* #e ! #email `As` #userEmail :* Nil)
123−-- > ( from (Table (#users `As` #u)
124−-- > & InnerJoin (Table (#emails `As` #e))
125−-- > (#u ! #id .== #e ! #user_id)) )
126−--
127−-- Now that we've defined the SQL side of things, we'll need a Haskell type
128−-- for users. We give the type `Generics.SOP.Generic` and
129−-- `Generics.SOP.HasDatatypeInfo` instances so that we can decode the rows
130−-- we receive when we run @getUsers@. Notice that the record fields of the
131−-- @User@ type match the column names of @getUsers@.
132−--
133−-- > data User = User { userName :: Text, userEmail :: Maybe Text }
134−-- > deriving (Show, GHC.Generic)
135−-- > instance SOP.Generic User
136−-- > instance SOP.HasDatatypeInfo User
137−--
138−-- Let's also create some users to add to the database.
139−--
140−-- > users :: [User]
141−-- > users =
142−-- > [ User "Alice" (Just "alice@gmail.com")
143−-- > , User "Bob" Nothing
144−-- > , User "Carole" (Just "carole@hotmail.com")
145−-- > ]
146−--
147−-- Now we can put together all the pieces into a program. The program
148−-- connects to the database, sets up the schema, inserts the user data
149−-- (using prepared statements as an optimization), queries the user
150−-- data and prints it out and finally closes the connection. We can thread
151−-- the changing schema information through by using the indexed `PQ` monad
152−-- transformer and when the schema doesn't change we can use `Monad` and
153−-- `MonadPQ` functionality.
154−--
155−-- > main :: IO ()
156−-- > main = void $
157−-- > withConnection "host=localhost port=5432 dbname=exampledb" . runPQ $
158−-- > define setup
159−-- > & pqThen session
160−-- > & thenDefine teardown
161−-- > where
162−-- > session = do
163−-- > idResults <- traversePrepared insertUser (Only . userName <$> users)
164−-- > ids <- traverse (fmap fromOnly . getRow (RowNumber 0)) idResults
165−-- > traversePrepared_ insertEmail (zip (ids :: [Int32]) (userEmail <$> users))
166−-- > usersResult <- runQuery getUsers
167−-- > usersRows <- getRows usersResult
168−-- > liftBase $ print (usersRows :: [User])
169−
170−module Squeal.PostgreSQL
171− ( module Squeal.PostgreSQL.Binary
172− , module Squeal.PostgreSQL.Definition
173− , module Squeal.PostgreSQL.Expression
174− , module Squeal.PostgreSQL.Manipulation
175− , module Squeal.PostgreSQL.PQ
176− , module Squeal.PostgreSQL.Query
177− , module Squeal.PostgreSQL.Schema
178− ) where
179−
180−import Squeal.PostgreSQL.Binary
181−import Squeal.PostgreSQL.Definition
182−import Squeal.PostgreSQL.Expression
183−import Squeal.PostgreSQL.Manipulation
184−import Squeal.PostgreSQL.PQ
185−import Squeal.PostgreSQL.Query
186−import Squeal.PostgreSQL.Schema
1+{-|
2+Module: Squeal.PostgreSQL
3+Description: Squeal export module
4+Copyright: (c) Eitan Chatav, 2019
5+Maintainer: eitan@morphism.tech
6+Stability: experimental
7+
8+Squeal is a deep embedding of [PostgreSQL](https://www.postgresql.org) in Haskell.
9+Let's see an example!
10+
11+First, we need some language extensions because Squeal uses modern GHC
12+features.
13+
14+>>> :set -XDataKinds -XDeriveGeneric -XOverloadedLabels -XFlexibleContexts
15+>>> :set -XOverloadedStrings -XTypeApplications -XTypeOperators -XGADTs
16+
17+We'll need some imports.
18+
19+>>> import Control.Monad.IO.Class (liftIO)
20+>>> import Data.Int (Int32)
21+>>> import Data.Text (Text)
22+>>> import Squeal.PostgreSQL
23+
24+We'll use generics to easily convert between Haskell and PostgreSQL values.
25+
26+>>> import qualified Generics.SOP as SOP
27+>>> import qualified GHC.Generics as GHC
28+
29+The first step is to define the schema of our database. This is where
30+we use @DataKinds@ and @TypeOperators@.
31+
32+>>> :{
33+type UsersColumns =
34+ '[ "id" ::: 'Def :=> 'NotNull 'PGint4
35+ , "name" ::: 'NoDef :=> 'NotNull 'PGtext ]
36+type UsersConstraints = '[ "pk_users" ::: 'PrimaryKey '["id"] ]
37+type EmailsColumns =
38+ '[ "id" ::: 'Def :=> 'NotNull 'PGint4
39+ , "user_id" ::: 'NoDef :=> 'NotNull 'PGint4
40+ , "email" ::: 'NoDef :=> 'Null 'PGtext ]
41+type EmailsConstraints =
42+ '[ "pk_emails" ::: 'PrimaryKey '["id"]
43+ , "fk_user_id" ::: 'ForeignKey '["user_id"] "users" '["id"] ]
44+type Schema =
45+ '[ "users" ::: 'Table (UsersConstraints :=> UsersColumns)
46+ , "emails" ::: 'Table (EmailsConstraints :=> EmailsColumns) ]
47+type Schemas = Public Schema
48+:}
49+
50+Notice the use of type operators.
51+
52+`:::` is used to pair an alias `GHC.TypeLits.Symbol` with a `SchemasType`, a `SchemumType`,
53+a `TableConstraint` or a `ColumnType`. It is intended to connote Haskell's @::@
54+operator.
55+
56+`:=>` is used to pair `TableConstraints` with a `ColumnsType`,
57+yielding a `TableType`, or to pair a `ColumnConstraint` with a `NullityType`,
58+yielding a `ColumnType`. It is intended to connote Haskell's @=>@ operator
59+
60+Next, we'll write `Definition`s to set up and tear down the schema. In
61+Squeal, a `Definition` like `createTable`, `alterTable` or `dropTable`
62+has two type parameters, corresponding to the schema
63+before being run and the schema after. We can compose definitions using `>>>`.
64+Here and in the rest of our commands we make use of overloaded
65+labels to refer to named tables and columns in our schema.
66+
67+>>> :{
68+let
69+ setup :: Definition (Public '[]) Schemas
70+ setup =
71+ createTable #users
72+ ( serial `as` #id :*
73+ (text & notNullable) `as` #name )
74+ ( primaryKey #id `as` #pk_users ) >>>
75+ createTable #emails
76+ ( serial `as` #id :*
77+ (int & notNullable) `as` #user_id :*
78+ (text & nullable) `as` #email )
79+ ( primaryKey #id `as` #pk_emails :*
80+ foreignKey #user_id #users #id
81+ OnDeleteCascade OnUpdateCascade `as` #fk_user_id )
82+:}
83+
84+We can easily see the generated SQL is unsurprising looking.
85+
86+>>> printSQL setup
87+CREATE TABLE "users" ("id" serial, "name" text NOT NULL, CONSTRAINT "pk_users" PRIMARY KEY ("id"));
88+CREATE TABLE "emails" ("id" serial, "user_id" int NOT NULL, "email" text NULL, CONSTRAINT "pk_emails" PRIMARY KEY ("id"), CONSTRAINT "fk_user_id" FOREIGN KEY ("user_id") REFERENCES "users" ("id") ON DELETE CASCADE ON UPDATE CASCADE);
89+
90+Notice that @setup@ starts with an empty public schema @(Public '[])@ and produces @Schemas@.
91+In our `createTable` commands we included `TableConstraint`s to define
92+primary and foreign keys, making them somewhat complex. Our @teardown@
93+`Definition` is simpler.
94+
95+>>> :{
96+let
97+ teardown :: Definition Schemas (Public '[])
98+ teardown = dropTable #emails >>> dropTable #users
99+:}
100+
101+>>> printSQL teardown
102+DROP TABLE "emails";
103+DROP TABLE "users";
104+
105+We'll need a Haskell type for @User@s. We give the type `Generics.SOP.Generic` and
106+`Generics.SOP.HasDatatypeInfo` instances so that we can encode and decode @User@s.
107+
108+>>> data User = User { userName :: Text, userEmail :: Maybe Text } deriving (Show, GHC.Generic)
109+>>> instance SOP.Generic User
110+>>> instance SOP.HasDatatypeInfo User
111+
112+Next, we'll write `Manipulation_`s to insert @User@s into our two tables.
113+A `Manipulation_` like `insertInto`, `update` or `deleteFrom`
114+has three type parameters, the schemas it refers to, input parameters
115+and an output row. When
116+we insert into the users table, we will need a parameter for the @name@
117+field but not for the @id@ field. Since it's serial, we can use a default
118+value. However, since the emails table refers to the users table, we will
119+need to retrieve the user id that the insert generates and insert it into
120+the emails table. We can do this in a single `Manipulation_` by using a
121+`with` statement.
122+
123+>>> :{
124+let
125+ insertUser :: Manipulation_ Schemas User ()
126+ insertUser = with (u `as` #u) e
127+ where
128+ u = insertInto #users
129+ (Values_ (Default `as` #id :* Set (param @1) `as` #name))
130+ OnConflictDoRaise (Returning_ (#id :* param @2 `as` #email))
131+ e = insertInto_ #emails $ Select
132+ (Default `as` #id :* Set (#u ! #id) `as` #user_id :* Set (#u ! #email) `as` #email)
133+ (from (common #u))
134+:}
135+
136+>>> printSQL insertUser
137+WITH "u" AS (INSERT INTO "users" ("id", "name") VALUES (DEFAULT, ($1 :: text)) RETURNING "id" AS "id", ($2 :: text) AS "email") INSERT INTO "emails" ("user_id", "email") SELECT "u"."id", "u"."email" FROM "u" AS "u"
138+
139+Next we write a `Query_` to retrieve users from the database. We're not
140+interested in the ids here, just the usernames and email addresses. We
141+need to use an `innerJoin` to get the right result. A `Query_` is like a
142+`Manipulation_` with the same kind of type parameters.
143+
144+>>> :{
145+let
146+ getUsers :: Query_ Schemas () User
147+ getUsers = select_
148+ (#u ! #name `as` #userName :* #e ! #email `as` #userEmail)
149+ ( from (table (#users `as` #u)
150+ & innerJoin (table (#emails `as` #e))
151+ (#u ! #id .== #e ! #user_id)) )
152+:}
153+
154+>>> printSQL getUsers
155+SELECT "u"."name" AS "userName", "e"."email" AS "userEmail" FROM "users" AS "u" INNER JOIN "emails" AS "e" ON ("u"."id" = "e"."user_id")
156+
157+Let's create some users to add to the database.
158+
159+>>> :{
160+let
161+ users :: [User]
162+ users =
163+ [ User "Alice" (Just "alice@gmail.com")
164+ , User "Bob" Nothing
165+ , User "Carole" (Just "carole@hotmail.com")
166+ ]
167+:}
168+
169+Now we can put together all the pieces into a program. The program
170+connects to the database, sets up the schema, inserts the user data
171+(using prepared statements as an optimization), queries the user
172+data and prints it out and finally closes the connection. We can thread
173+the changing schema information through by using the indexed `PQ` monad
174+transformer and when the schema doesn't change we can use `Monad` and
175+`MonadPQ` functionality.
176+
177+>>> :{
178+let
179+ session :: PQ Schemas Schemas IO ()
180+ session = do
181+ _ <- traversePrepared_ insertUser users
182+ usersResult <- runQuery getUsers
183+ usersRows <- getRows usersResult
184+ liftIO $ print (usersRows :: [User])
185+in
186+ withConnection "host=localhost port=5432 dbname=exampledb" $
187+ define setup
188+ & pqThen session
189+ & pqThen (define teardown)
190+:}
191+[User {userName = "Alice", userEmail = Just "alice@gmail.com"},User {userName = "Bob", userEmail = Nothing},User {userName = "Carole", userEmail = Just "carole@hotmail.com"}]
192+-}
193+module Squeal.PostgreSQL (module X, RenderSQL(..), printSQL) where
194+
195+import Squeal.PostgreSQL.Alias as X
196+import Squeal.PostgreSQL.Binary as X
197+import Squeal.PostgreSQL.Definition as X
198+import Squeal.PostgreSQL.Definition.Function as X
199+import Squeal.PostgreSQL.Definition.Index as X
200+import Squeal.PostgreSQL.Definition.Schema as X
201+import Squeal.PostgreSQL.Definition.Table as X
202+import Squeal.PostgreSQL.Definition.Table.Constraint as X
203+import Squeal.PostgreSQL.Definition.Type as X
204+import Squeal.PostgreSQL.Definition.View as X
205+import Squeal.PostgreSQL.Expression as X
206+import Squeal.PostgreSQL.Expression.Aggregate as X
207+import Squeal.PostgreSQL.Expression.Collection as X
208+import Squeal.PostgreSQL.Expression.Comparison as X
209+import Squeal.PostgreSQL.Expression.Json as X
210+import Squeal.PostgreSQL.Expression.Literal as X
211+import Squeal.PostgreSQL.Expression.Logic as X
212+import Squeal.PostgreSQL.Expression.Math as X
213+import Squeal.PostgreSQL.Expression.Null as X
214+import Squeal.PostgreSQL.Expression.Parameter as X
215+import Squeal.PostgreSQL.Expression.Range as X
216+import Squeal.PostgreSQL.Expression.Set as X
217+import Squeal.PostgreSQL.Expression.Sort as X
218+import Squeal.PostgreSQL.Expression.Subquery as X
219+import Squeal.PostgreSQL.Expression.Text as X
220+import Squeal.PostgreSQL.Expression.TextSearch as X
221+import Squeal.PostgreSQL.Expression.Time as X
222+import Squeal.PostgreSQL.Expression.Type as X
223+import Squeal.PostgreSQL.Expression.Window as X
224+import Squeal.PostgreSQL.List as X
225+import Squeal.PostgreSQL.Manipulation as X
226+import Squeal.PostgreSQL.Migration as X
227+import Squeal.PostgreSQL.PG as X
228+import Squeal.PostgreSQL.Pool as X
229+import Squeal.PostgreSQL.PQ as X
230+import Squeal.PostgreSQL.Query as X
231+import Squeal.PostgreSQL.Render (RenderSQL(..), printSQL)
232+import Squeal.PostgreSQL.Schema as X
233+import Squeal.PostgreSQL.Transaction as X
squeal-postgresql/src/Squeal/PostgreSQL/Alias.hsnew file+249
@@ -0,0 +1,249 @@
1+{-|
2+Module: Squeal.PostgreSQL.Alias
3+Description: Aliases
4+Copyright: (c) Eitan Chatav, 2019
5+Maintainer: eitan@morphism.tech
6+Stability: experimental
7+
8+This module embeds Postgres's alias system in Haskell in
9+a typesafe fashion. Thanks to GHC's @OverloadedLabels@ extension,
10+Squeal can reference aliases by prepending with a @#@.
11+-}
12+
13+{-# LANGUAGE
14+ AllowAmbiguousTypes
15+ , ConstraintKinds
16+ , DeriveAnyClass
17+ , DeriveGeneric
18+ , FlexibleContexts
19+ , FlexibleInstances
20+ , FunctionalDependencies
21+ , GADTs
22+ , LambdaCase
23+ , OverloadedStrings
24+ , QuantifiedConstraints
25+ , RankNTypes
26+ , ScopedTypeVariables
27+ , StandaloneDeriving
28+ , TypeApplications
29+ , TypeFamilyDependencies
30+ , TypeInType
31+ , TypeOperators
32+ , UndecidableInstances
33+ , UndecidableSuperClasses
34+#-}
35+
36+module Squeal.PostgreSQL.Alias
37+ ( (:::)
38+ , Alias (..)
39+ , IsLabel (..)
40+ , Aliased (As)
41+ , Aliasable (as)
42+ , renderAliased
43+ , Has
44+ , HasUnique
45+ , HasAll
46+ , HasIn
47+ , QualifiedAlias (..)
48+ , IsQualified (..)
49+ -- * Grouping
50+ , Grouping (..)
51+ , GroupedBy
52+ ) where
53+
54+import Control.DeepSeq
55+import Data.ByteString (ByteString)
56+import Data.String (fromString)
57+import GHC.OverloadedLabels
58+import GHC.TypeLits
59+
60+import qualified Generics.SOP as SOP
61+import qualified GHC.Generics as GHC
62+
63+import Squeal.PostgreSQL.List
64+import Squeal.PostgreSQL.Render
65+
66+-- $setup
67+-- >>> import Squeal.PostgreSQL
68+
69+-- | The alias operator `:::` is like a promoted version of `As`,
70+-- a type level pair between an alias and some type.
71+type (:::) (alias :: Symbol) ty = '(alias,ty)
72+infixr 6 :::
73+
74+
75+-- | `Grouping` is an auxiliary namespace, created by
76+-- @GROUP BY@ clauses (`Squeal.PostgreSQL.Query.group`), and used
77+-- for typesafe aggregation
78+data Grouping
79+ = Ungrouped -- ^ no aggregation permitted
80+ | Grouped [(Symbol,Symbol)] -- ^ aggregation required for any column which is not grouped
81+
82+{- | A `GroupedBy` constraint indicates that a table qualified column is
83+a member of the auxiliary namespace created by @GROUP BY@ clauses and thus,
84+may be called in an output `Squeal.PostgreSQL.Expression.Expression` without aggregating.
85+-}
86+class (KnownSymbol table, KnownSymbol column)
87+ => GroupedBy table column bys where
88+instance {-# OVERLAPPING #-} (KnownSymbol table, KnownSymbol column)
89+ => GroupedBy table column ('(table,column) ': bys)
90+instance {-# OVERLAPPABLE #-}
91+ ( KnownSymbol table
92+ , KnownSymbol column
93+ , GroupedBy table column bys
94+ ) => GroupedBy table column (tabcol ': bys)
95+
96+-- | `Alias`es are proxies for a type level string or `Symbol`
97+-- and have an `IsLabel` instance so that with @-XOverloadedLabels@
98+--
99+-- >>> :set -XOverloadedLabels
100+-- >>> #foobar :: Alias "foobar"
101+-- Alias
102+data Alias (alias :: Symbol) = Alias
103+ deriving (Eq,GHC.Generic,Ord,Show,NFData)
104+instance alias1 ~ alias2 => IsLabel alias1 (Alias alias2) where
105+ fromLabel = Alias
106+instance aliases ~ '[alias] => IsLabel alias (NP Alias aliases) where
107+ fromLabel = fromLabel SOP.:* Nil
108+-- | >>> printSQL (#jimbob :: Alias "jimbob")
109+-- "jimbob"
110+instance KnownSymbol alias => RenderSQL (Alias alias) where
111+ renderSQL = doubleQuoted . fromString . symbolVal
112+
113+-- >>> printSQL (#jimbob :* #kandi :: NP Alias '["jimbob", "kandi"])
114+-- "jimbob", "kandi"
115+instance SOP.All KnownSymbol aliases => RenderSQL (NP Alias aliases) where
116+ renderSQL
117+ = commaSeparated
118+ . SOP.hcollapse
119+ . SOP.hcmap (SOP.Proxy @KnownSymbol) (SOP.K . renderSQL)
120+
121+-- | The `As` operator is used to name an expression. `As` is like a demoted
122+-- version of `:::`.
123+--
124+-- >>> Just "hello" `As` #hi :: Aliased Maybe ("hi" ::: String)
125+-- As (Just "hello") Alias
126+data Aliased expression aliased where
127+ As
128+ :: KnownSymbol alias
129+ => expression ty
130+ -> Alias alias
131+ -> Aliased expression (alias ::: ty)
132+deriving instance Show (expression ty)
133+ => Show (Aliased expression (alias ::: ty))
134+deriving instance Eq (expression ty)
135+ => Eq (Aliased expression (alias ::: ty))
136+deriving instance Ord (expression ty)
137+ => Ord (Aliased expression (alias ::: ty))
138+instance (alias0 ~ alias1, alias0 ~ alias2, KnownSymbol alias2)
139+ => IsLabel alias0 (Aliased Alias (alias1 ::: alias2)) where
140+ fromLabel = fromLabel @alias2 `As` fromLabel @alias1
141+
142+-- | The `Aliasable` class provides a way to scrap your `Nil`s
143+-- in an `NP` list of `Aliased` expressions.
144+class KnownSymbol alias => Aliasable alias expression aliased
145+ | aliased -> expression
146+ , aliased -> alias
147+ where as :: expression -> Alias alias -> aliased
148+instance (KnownSymbol alias, aliased ~ (alias ::: ty)) => Aliasable alias
149+ (expression ty)
150+ (Aliased expression aliased)
151+ where
152+ as = As
153+instance (KnownSymbol alias, tys ~ '[alias ::: ty]) => Aliasable alias
154+ (expression ty)
155+ (NP (Aliased expression) tys)
156+ where
157+ expression `as` alias = expression `As` alias SOP.:* Nil
158+
159+-- | >>> let renderMaybe = fromString . maybe "Nothing" (const "Just")
160+-- >>> renderAliased renderMaybe (Just (3::Int) `As` #an_int)
161+-- "Just AS \"an_int\""
162+renderAliased
163+ :: (forall ty. expression ty -> ByteString)
164+ -> Aliased expression aliased
165+ -> ByteString
166+renderAliased render (expression `As` alias) =
167+ render expression <> " AS " <> renderSQL alias
168+
169+-- | @HasUnique alias fields field@ is a constraint that proves that
170+-- @fields@ is a singleton of @alias ::: field@.
171+type HasUnique alias fields field = fields ~ '[alias ::: field]
172+
173+-- | @Has alias fields field@ is a constraint that proves that
174+-- @fields@ has a field of @alias ::: field@, inferring @field@
175+-- from @alias@ and @fields@.
176+class KnownSymbol alias =>
177+ Has (alias :: Symbol) (fields :: [(Symbol,kind)]) (field :: kind)
178+ | alias fields -> field where
179+instance {-# OVERLAPPING #-} KnownSymbol alias
180+ => Has alias (alias ::: field ': fields) field
181+instance {-# OVERLAPPABLE #-} (KnownSymbol alias, Has alias fields field)
182+ => Has alias (field' ': fields) field
183+
184+{-| @HasIn fields (alias ::: field)@ is a constraint that proves that
185+@fields@ has a field of @alias ::: field@. It is used in @UPDATE@s to
186+choose which subfields to update.
187+-}
188+class HasIn fields field where
189+instance (Has alias fields field) => HasIn fields (alias ::: field) where
190+
191+-- | `HasAll` extends `Has` to take lists of @aliases@ and @fields@ and infer
192+-- a list of @subfields@.
193+class
194+ ( SOP.All KnownSymbol aliases
195+ ) => HasAll
196+ (aliases :: [Symbol])
197+ (fields :: [(Symbol,kind)])
198+ (subfields :: [(Symbol,kind)])
199+ | aliases fields -> subfields where
200+instance {-# OVERLAPPING #-} HasAll '[] fields '[]
201+instance {-# OVERLAPPABLE #-}
202+ (Has alias fields field, HasAll aliases fields subfields)
203+ => HasAll (alias ': aliases) fields (alias ::: field ': subfields)
204+
205+-- | Analagous to `IsLabel`, the constraint
206+-- `IsQualified` defines `!` for a column alias qualified
207+-- by a table alias.
208+class IsQualified table column expression where
209+ (!) :: Alias table -> Alias column -> expression
210+ infixl 9 !
211+instance IsQualified table column (Alias table, Alias column) where (!) = (,)
212+
213+{-| `QualifiedAlias`es enables multi-schema support by allowing a reference
214+to a `Squeal.PostgreSQL.Schema.Table`, `Squeal.PostgreSQL.Schema.Typedef`
215+or `Squeal.PostgreSQL.Schema.View` to be qualified by their schemas. By default,
216+a qualifier of @public@ is provided.
217+
218+>>> :{
219+let
220+ alias1 :: QualifiedAlias "sch" "tab"
221+ alias1 = #sch ! #tab
222+ alias2 :: QualifiedAlias "public" "vw"
223+ alias2 = #vw
224+in printSQL alias1 >> printSQL alias2
225+:}
226+"sch"."tab"
227+"vw"
228+-}
229+data QualifiedAlias (qualifier :: Symbol) (alias :: Symbol) = QualifiedAlias
230+ deriving (Eq,GHC.Generic,Ord,Show,NFData)
231+instance (q ~ q', a ~ a') => IsQualified q a (QualifiedAlias q' a') where
232+ _!_ = QualifiedAlias
233+instance (q' ~ "public", a ~ a') => IsLabel a (QualifiedAlias q' a') where
234+ fromLabel = QualifiedAlias
235+instance (q0 ~ q1, a0 ~ a1, a1 ~ a2, KnownSymbol a2) =>
236+ IsQualified q0 a0 (Aliased (QualifiedAlias q1) (a1 ::: a2)) where
237+ _!_ = QualifiedAlias `As` Alias
238+instance (q ~ "public", a0 ~ a1, a1 ~ a2, KnownSymbol a2) =>
239+ IsLabel a0 (Aliased (QualifiedAlias q) (a1 ::: a2)) where
240+ fromLabel = QualifiedAlias `As` Alias
241+
242+instance (KnownSymbol q, KnownSymbol a)
243+ => RenderSQL (QualifiedAlias q a) where
244+ renderSQL _ =
245+ let
246+ qualifier = renderSQL (Alias @q)
247+ alias = renderSQL (Alias @a)
248+ in
249+ if qualifier == "\"public\"" then alias else qualifier <> "." <> alias
squeal-postgresql/src/Squeal/PostgreSQL/Binary.hs+694−109
@@ -5,22 +5,192 @@ Copyright: (c) Eitan Chatav, 2017
55Maintainer: eitan@morphism.tech
66Stability: experimental
77
8−Binary encoding and decoding between Haskell and PostgreSQL types.
8+This module provides binary encoding and decoding between Haskell and PostgreSQL types.
9+
10+Instances are governed by the `SOP.Generic` and `SOP.HasDatatypeInfo` typeclasses, so you absolutely
11+do not need to define your own instances to decode retrieved rows into Haskell values or
12+to encode Haskell values into statement parameters.
13+
14+Let's see some examples. We'll need some imports
15+
16+>>> import Data.Int (Int16)
17+>>> import Data.Text (Text)
18+>>> import Control.Monad (void)
19+>>> import Control.Monad.IO.Class (liftIO)
20+>>> import Squeal.PostgreSQL
21+
22+Define a Haskell datatype @Row@ that will serve as both the input and output of a simple
23+round trip query.
24+
25+>>> data Row = Row { col1 :: Int16, col2 :: Text, col3 :: Maybe Bool } deriving (Eq, GHC.Generic)
26+>>> instance Generic Row
27+>>> instance HasDatatypeInfo Row
28+>>> :{
29+let
30+ roundTrip :: Query_ (Public '[]) Row Row
31+ roundTrip = values_ $
32+ parameter @1 int2 `as` #col1 :*
33+ parameter @2 text `as` #col2 :*
34+ parameter @3 bool `as` #col3
35+:}
36+
37+So long as we can encode the parameters and then decode the result of the query,
38+the input and output should be equal.
39+
40+>>> let input = Row 2 "hi" (Just True)
41+>>> :{
42+withConnection "host=localhost port=5432 dbname=exampledb" $ do
43+ result <- runQueryParams roundTrip input
44+ Just output <- firstRow result
45+ liftIO . print $ input == output
46+:}
47+True
48+
49+In addition to being able to encode and decode basic Haskell types
50+like `Int16` and `Data.Text.Text`, Squeal permits you to encode and decode Haskell types to
51+Postgres array, enumerated and composite types and json. Let's see another example,
52+this time using the `Vector` type which corresponds to variable length arrays
53+and homogeneous tuples which correspond to fixed length arrays. We can even
54+create multi-dimensional fixed length arrays.
55+
56+>>> :{
57+data Row = Row
58+ { col1 :: VarArray (Vector Int16)
59+ , col2 :: FixArray (Maybe Int16,Maybe Int16)
60+ , col3 :: FixArray ((Int16,Int16),(Int16,Int16),(Int16,Int16))
61+ } deriving (Eq, GHC.Generic)
62+:}
63+
64+>>> instance Generic Row
65+>>> instance HasDatatypeInfo Row
66+
67+Once again, we define a simple round trip query.
68+
69+>>> :{
70+let
71+ roundTrip :: Query_ (Public '[]) Row Row
72+ roundTrip = values_ $
73+ parameter @1 (int2 & vararray) `as` #col1 :*
74+ parameter @2 (int2 & fixarray @'[2]) `as` #col2 :*
75+ parameter @3 (int2 & fixarray @'[3,2]) `as` #col3
76+:}
77+
78+>>> :set -XOverloadedLists
79+>>> let input = Row (VarArray [1,2]) (FixArray (Just 1,Nothing)) (FixArray ((1,2),(3,4),(5,6)))
80+>>> :{
81+withConnection "host=localhost port=5432 dbname=exampledb" $ do
82+ result <- runQueryParams roundTrip input
83+ Just output <- firstRow result
84+ liftIO . print $ input == output
85+:}
86+True
87+
88+Enumerated (enum) types are data types that comprise a static, ordered set of values.
89+They are equivalent to Haskell algebraic data types whose constructors are nullary.
90+An example of an enum type might be the days of the week,
91+or a set of status values for a piece of data.
92+
93+>>> data Schwarma = Beef | Lamb | Chicken deriving (Eq, Show, GHC.Generic)
94+>>> instance Generic Schwarma
95+>>> instance HasDatatypeInfo Schwarma
96+
97+A composite type represents the structure of a row or record;
98+it is essentially just a list of field names and their data types.
99+
100+>>> data Person = Person {name :: Text, age :: Int32} deriving (Eq, Show, GHC.Generic)
101+>>> instance Generic Person
102+>>> instance HasDatatypeInfo Person
103+>>> instance Aeson.FromJSON Person
104+>>> instance Aeson.ToJSON Person
105+
106+We can create the equivalent Postgres types directly from their Haskell types.
107+
108+>>> :{
109+type Schema =
110+ '[ "schwarma" ::: 'Typedef (PG (Enumerated Schwarma))
111+ , "person" ::: 'Typedef (PG (Composite Person))
112+ ]
113+:}
114+
115+>>> :{
116+let
117+ setup :: Definition (Public '[]) (Public Schema)
118+ setup =
119+ createTypeEnumFrom @Schwarma #schwarma >>>
120+ createTypeCompositeFrom @Person #person
121+:}
122+
123+Let's demonstrate how to associate our Haskell types @Schwarma@ and @Person@
124+with enumerated, composite or json types in Postgres. First create a Haskell
125+@Row@ type using the `Enumerated`, `Composite` and `Json` newtypes as fields.
126+
127+>>> :{
128+data Row = Row
129+ { schwarma :: Enumerated Schwarma
130+ , person1 :: Composite Person
131+ , person2 :: Json Person
132+ } deriving (Eq, GHC.Generic)
133+:}
134+
135+>>> instance Generic Row
136+>>> instance HasDatatypeInfo Row
137+>>> :{
138+let
139+ input = Row
140+ (Enumerated Chicken)
141+ (Composite (Person "Faisal" 24))
142+ (Json (Person "Ahmad" 48))
143+:}
144+
145+Once again, define a round trip query.
146+
147+>>> :{
148+let
149+ roundTrip :: Query_ (Public Schema) Row Row
150+ roundTrip = values_ $
151+ parameter @1 (typedef #schwarma) `as` #schwarma :*
152+ parameter @2 (typedef #person) `as` #person1 :*
153+ parameter @3 json `as` #person2
154+:}
155+
156+Finally, we can drop our type definitions.
157+
158+>>> :{
159+let
160+ teardown :: Definition (Public Schema) (Public '[])
161+ teardown = dropType #schwarma >>> dropType #person
162+:}
163+
164+Now let's run it.
165+
166+>>> :{
167+let
168+ session = do
169+ result <- runQueryParams roundTrip input
170+ Just output <- firstRow result
171+ liftIO . print $ input == output
172+in
173+ withConnection "host=localhost port=5432 dbname=exampledb" $
174+ define setup
175+ & pqThen session
176+ & pqThen (define teardown)
177+:}
178+True
9179-}
10180
11181{-# LANGUAGE
12− ConstraintKinds
13− , DataKinds
14− , DefaultSignatures
182+ AllowAmbiguousTypes
15183 , DeriveFoldable
16184 , DeriveFunctor
17185 , DeriveGeneric
18186 , DeriveTraversable
187+ , DefaultSignatures
19188 , FlexibleContexts
20189 , FlexibleInstances
190+ , FunctionalDependencies
21191 , GADTs
22192 , LambdaCase
23− , KindSignatures
193+ , OverloadedStrings
24194 , MultiParamTypeClasses
25195 , ScopedTypeVariables
26196 , TypeApplications
@@ -28,40 +198,62 @@ Binary encoding and decoding between Haskell and PostgreSQL types.
28198 , TypeInType
29199 , TypeOperators
30200 , UndecidableInstances
201+ , UndecidableSuperClasses
31202#-}
32203
33204module Squeal.PostgreSQL.Binary
34205 ( -- * Encoding
35206 ToParam (..)
36− , ToColumnParam (..)
37207 , ToParams (..)
208+ , ToNullityParam (..)
209+ , ToField (..)
210+ , ToFixArray (..)
38211 -- * Decoding
39212 , FromValue (..)
40− , FromColumnValue (..)
41213 , FromRow (..)
214+ , FromField (..)
215+ , FromFixArray (..)
42216 -- * Only
43217 , Only (..)
218+ -- * Oid
219+ , OidOf (..)
220+ , OidOfParam (..)
221+ , OidOfField (..)
44222 ) where
45223
46−import Data.Aeson hiding (Null)
224+import BinaryParser
225+import ByteString.StrictBuilder (builderLength, int32BE, int64BE, word32BE)
226+import Control.Arrow (left)
227+import Control.Monad
47228import Data.Int
48229import Data.Kind
49230import Data.Scientific
50231import Data.Time
51−import Data.UUID
232+import Data.UUID.Types
233+import Data.Vector (Vector)
52234import Data.Word
235+import Foreign.C.Types (CUInt(CUInt))
53236import Generics.SOP
237+import Generics.SOP.Record
54238import GHC.TypeLits
55239import Network.IP.Addr
56240
57−import qualified Data.ByteString.Lazy as Lazy
58−import qualified Data.ByteString as Strict hiding (unpack)
59−import qualified Data.Text.Lazy as Lazy
60−import qualified Data.Text as Strict
241+import qualified Data.Aeson as Aeson
242+import qualified Data.ByteString.Lazy as Lazy (ByteString)
243+import qualified Data.ByteString.Lazy as Lazy.ByteString
244+import qualified Data.ByteString as Strict (ByteString)
245+import qualified Data.Text.Lazy as Lazy (Text)
246+import qualified Data.Text as Strict (Text)
247+import qualified Data.Text as Strict.Text
248+import qualified Data.Vector as Vector
249+import qualified Database.PostgreSQL.LibPQ as LibPQ
61250import qualified GHC.Generics as GHC
62251import qualified PostgreSQL.Binary.Decoding as Decoding
63252import qualified PostgreSQL.Binary.Encoding as Encoding
64253
254+import Squeal.PostgreSQL.Alias
255+import Squeal.PostgreSQL.List
256+import Squeal.PostgreSQL.PG
65257import Squeal.PostgreSQL.Schema
66258
67259-- | A `ToParam` constraint gives an encoding of a Haskell `Type` into
@@ -85,19 +277,20 @@ class ToParam (x :: Type) (pg :: PGType) where
85277 toParam :: x -> K Encoding.Encoding pg
86278instance ToParam Bool 'PGbool where toParam = K . Encoding.bool
87279instance ToParam Int16 'PGint2 where toParam = K . Encoding.int2_int16
88−instance ToParam Word16 'PGint2 where toParam = K . Encoding.int2_word16
89280instance ToParam Int32 'PGint4 where toParam = K . Encoding.int4_int32
90−instance ToParam Word32 'PGint4 where toParam = K . Encoding.int4_word32
91281instance ToParam Int64 'PGint8 where toParam = K . Encoding.int8_int64
92−instance ToParam Word64 'PGint8 where toParam = K . Encoding.int8_word64
282+instance ToParam Oid 'PGoid where toParam = K . Encoding.int4_word32 . getOid
93283instance ToParam Float 'PGfloat4 where toParam = K . Encoding.float4
94284instance ToParam Double 'PGfloat8 where toParam = K . Encoding.float8
95285instance ToParam Scientific 'PGnumeric where toParam = K . Encoding.numeric
286+instance ToParam Money 'PGmoney where toParam = K . Encoding.int8_int64 . cents
96287instance ToParam UUID 'PGuuid where toParam = K . Encoding.uuid
97288instance ToParam (NetAddr IP) 'PGinet where toParam = K . Encoding.inet
98289instance ToParam Char ('PGchar 1) where toParam = K . Encoding.char_utf8
99290instance ToParam Strict.Text 'PGtext where toParam = K . Encoding.text_strict
100291instance ToParam Lazy.Text 'PGtext where toParam = K . Encoding.text_lazy
292+instance ToParam String 'PGtext where
293+ toParam = K . Encoding.text_strict . Strict.Text.pack
101294instance ToParam Strict.ByteString 'PGbytea where
102295 toParam = K . Encoding.bytea_strict
103296instance ToParam Lazy.ByteString 'PGbytea where
@@ -111,142 +304,518 @@ instance ToParam LocalTime 'PGtimestamp where
111304instance ToParam UTCTime 'PGtimestamptz where
112305 toParam = K . Encoding.timestamptz_int
113306instance ToParam DiffTime 'PGinterval where toParam = K . Encoding.interval_int
114−instance ToParam Value 'PGjson where toParam = K . Encoding.json_ast
115−instance ToParam Value 'PGjsonb where toParam = K . Encoding.jsonb_ast
116−
117−-- | A `ToColumnParam` constraint lifts the `ToParam` encoding
118−-- of a `Type` to a `ColumnType`, encoding `Maybe`s to `Null`s. You should
119−-- not define instances of `ToColumnParam`, just use the provided instances.
120−class ToColumnParam (x :: Type) (ty :: NullityType) where
121− -- | >>> toColumnParam @Int16 @('NotNull 'PGint2) 0
122− -- K (Just "\NUL\NUL")
123− --
124− -- >>> toColumnParam @(Maybe Int16) @('Null 'PGint2) (Just 0)
125− -- K (Just "\NUL\NUL")
126− --
127− -- >>> toColumnParam @(Maybe Int16) @('Null 'PGint2) Nothing
128− -- K Nothing
129− toColumnParam :: x -> K (Maybe Strict.ByteString) ty
130−instance ToParam x pg => ToColumnParam x ('NotNull pg) where
131− toColumnParam = K . Just . Encoding.encodingBytes . unK . toParam @x @pg
132−instance ToParam x pg => ToColumnParam (Maybe x) ('Null pg) where
133− toColumnParam = K . fmap (Encoding.encodingBytes . unK . toParam @x @pg)
307+instance ToParam Aeson.Value 'PGjson where toParam = K . Encoding.json_ast
308+instance ToParam Aeson.Value 'PGjsonb where toParam = K . Encoding.jsonb_ast
309+instance Aeson.ToJSON x => ToParam (Json x) 'PGjson where
310+ toParam = K . Encoding.json_bytes
311+ . Lazy.ByteString.toStrict . Aeson.encode . getJson
312+instance Aeson.ToJSON x => ToParam (Jsonb x) 'PGjsonb where
313+ toParam = K . Encoding.jsonb_bytes
314+ . Lazy.ByteString.toStrict . Aeson.encode . getJsonb
315+instance (ToNullityParam x ty, ty ~ nullity pg, OidOf pg)
316+ => ToParam (VarArray [x]) ('PGvararray ty) where
317+ toParam = K
318+ . Encoding.array_foldable
319+ (getOid (oidOf @pg)) (unK . toNullityParam @x @ty)
320+ . getVarArray
321+instance (ToParam x pg, OidOf pg)
322+ => ToParam (VarArray (Vector x)) ('PGvararray ('NotNull pg)) where
323+ toParam = K
324+ . Encoding.array_vector (getOid (oidOf @pg)) (unK . toParam @x @pg)
325+ . getVarArray
326+instance (ToParam x pg, OidOf pg)
327+ => ToParam (VarArray (Vector (Maybe x))) ('PGvararray ('Null pg)) where
328+ toParam = K
329+ . Encoding.nullableArray_vector
330+ (getOid (oidOf @pg)) (unK . toParam @x @pg)
331+ . getVarArray
332+instance (ToFixArray x dims ty, ty ~ nullity pg, OidOf pg)
333+ => ToParam (FixArray x) ('PGfixarray dims ty) where
334+ toParam = K . Encoding.array (getOid (oidOf @pg))
335+ . unK . unK . toFixArray @x @dims @ty . getFixArray
336+instance
337+ ( IsEnumType x
338+ , HasDatatypeInfo x
339+ , LabelsPG x ~ labels
340+ ) => ToParam (Enumerated x) ('PGenum labels) where
341+ toParam =
342+ let
343+ gshowConstructor :: NP ConstructorInfo xss -> SOP I xss -> String
344+ gshowConstructor Nil _ = ""
345+ gshowConstructor (constructor :* _) (SOP (Z _)) =
346+ constructorName constructor
347+ gshowConstructor (_ :* constructors) (SOP (S xs)) =
348+ gshowConstructor constructors (SOP xs)
349+ in
350+ K . Encoding.text_strict
351+ . Strict.Text.pack
352+ . gshowConstructor (constructorInfo (datatypeInfo (Proxy @x)))
353+ . from
354+ . getEnumerated
355+instance
356+ ( SListI fields
357+ , IsRecord x xs
358+ , AllZip ToField xs fields
359+ , All OidOfField fields
360+ ) => ToParam (Composite x) ('PGcomposite fields) where
361+ toParam =
362+ let
363+
364+ encoders = htrans (Proxy @ToField) toField
365+
366+ composite
367+ :: All OidOfField row
368+ => NP (K (Maybe Encoding.Encoding)) row
369+ -> K Encoding.Encoding ('PGcomposite row)
370+ composite fields = K $
371+ -- <number of fields: 4 bytes>
372+ -- [for each field]
373+ -- <OID of field's type: sizeof(Oid) bytes>
374+ -- [if value is NULL]
375+ -- <-1: 4 bytes>
376+ -- [else]
377+ -- <length of value: 4 bytes>
378+ -- <value: <length> bytes>
379+ -- [end if]
380+ -- [end for]
381+ int32BE (fromIntegral (lengthSList (Proxy @xs))) <>
382+ let
383+ each
384+ :: OidOfField field
385+ => K (Maybe Encoding.Encoding) field
386+ -> Encoding.Encoding
387+ each (K field :: K (Maybe Encoding.Encoding) field) =
388+ word32BE (getOid (oidOfField @field))
389+ <> case field of
390+ Nothing -> int64BE (-1)
391+ Just value ->
392+ int32BE (fromIntegral (builderLength value))
393+ <> value
394+ in
395+ hcfoldMap (Proxy @OidOfField) each fields
396+
397+ in
398+ composite . encoders . toRecord . getComposite
399+
400+-- | The object identifier of a `PGType`.
401+--
402+-- >>> :set -XTypeApplications
403+-- >>> oidOf @'PGbool
404+-- Oid 16
405+class OidOf (ty :: PGType) where oidOf :: LibPQ.Oid
406+instance OidOf 'PGbool where oidOf = LibPQ.Oid 16
407+instance OidOf ('PGfixarray ns (null 'PGbool)) where oidOf = LibPQ.Oid 1000
408+instance OidOf ('PGvararray (null 'PGbool)) where oidOf = LibPQ.Oid 1000
409+instance OidOf 'PGint2 where oidOf = LibPQ.Oid 21
410+instance OidOf ('PGfixarray ns (null 'PGint2)) where oidOf = LibPQ.Oid 1005
411+instance OidOf ('PGvararray (null 'PGint2)) where oidOf = LibPQ.Oid 1005
412+instance OidOf 'PGint4 where oidOf = LibPQ.Oid 23
413+instance OidOf ('PGfixarray ns (null 'PGint4)) where oidOf = LibPQ.Oid 1007
414+instance OidOf ('PGvararray (null 'PGint4)) where oidOf = LibPQ.Oid 1007
415+instance OidOf 'PGint8 where oidOf = LibPQ.Oid 20
416+instance OidOf ('PGfixarray ns (null 'PGint8)) where oidOf = LibPQ.Oid 1016
417+instance OidOf ('PGvararray (null 'PGint8)) where oidOf = LibPQ.Oid 1016
418+instance OidOf 'PGnumeric where oidOf = LibPQ.Oid 1700
419+instance OidOf ('PGfixarray ns (null 'PGnumeric)) where oidOf = LibPQ.Oid 1231
420+instance OidOf ('PGvararray (null 'PGnumeric)) where oidOf = LibPQ.Oid 1231
421+instance OidOf 'PGfloat4 where oidOf = LibPQ.Oid 700
422+instance OidOf ('PGfixarray ns (null 'PGfloat4)) where oidOf = LibPQ.Oid 1021
423+instance OidOf ('PGvararray (null 'PGfloat4)) where oidOf = LibPQ.Oid 1021
424+instance OidOf 'PGfloat8 where oidOf = LibPQ.Oid 701
425+instance OidOf ('PGfixarray ns (null 'PGfloat8)) where oidOf = LibPQ.Oid 1022
426+instance OidOf ('PGvararray (null 'PGfloat8)) where oidOf = LibPQ.Oid 1022
427+instance OidOf 'PGmoney where oidOf = LibPQ.Oid 790
428+instance OidOf ('PGfixarray ns (null 'PGmoney)) where oidOf = LibPQ.Oid 791
429+instance OidOf ('PGvararray (null 'PGmoney)) where oidOf = LibPQ.Oid 791
430+instance OidOf ('PGchar n) where oidOf = LibPQ.Oid 18
431+instance OidOf ('PGfixarray ns (null ('PGchar n))) where oidOf = LibPQ.Oid 1002
432+instance OidOf ('PGvararray (null ('PGchar n))) where oidOf = LibPQ.Oid 1002
433+instance OidOf ('PGvarchar n) where oidOf = LibPQ.Oid 1043
434+instance OidOf ('PGfixarray ns (null ('PGvarchar n))) where oidOf = LibPQ.Oid 1015
435+instance OidOf ('PGvararray (null ('PGvarchar n))) where oidOf = LibPQ.Oid 1015
436+instance OidOf 'PGtext where oidOf = LibPQ.Oid 25
437+instance OidOf ('PGfixarray ns (null 'PGtext)) where oidOf = LibPQ.Oid 1009
438+instance OidOf ('PGvararray (null 'PGtext)) where oidOf = LibPQ.Oid 1009
439+instance OidOf 'PGbytea where oidOf = LibPQ.Oid 17
440+instance OidOf ('PGfixarray ns (null 'PGbytea)) where oidOf = LibPQ.Oid 1001
441+instance OidOf ('PGvararray (null 'PGbytea)) where oidOf = LibPQ.Oid 1001
442+instance OidOf 'PGtimestamp where oidOf = LibPQ.Oid 1114
443+instance OidOf ('PGfixarray ns (null 'PGtimestamp)) where oidOf = LibPQ.Oid 1115
444+instance OidOf ('PGvararray (null 'PGtimestamp)) where oidOf = LibPQ.Oid 1115
445+instance OidOf 'PGtimestamptz where oidOf = LibPQ.Oid 1184
446+instance OidOf ('PGfixarray ns (null 'PGtimestamptz)) where oidOf = LibPQ.Oid 1185
447+instance OidOf ('PGvararray (null 'PGtimestamptz)) where oidOf = LibPQ.Oid 1185
448+instance OidOf 'PGdate where oidOf = LibPQ.Oid 1082
449+instance OidOf ('PGfixarray ns (null 'PGdate)) where oidOf = LibPQ.Oid 1182
450+instance OidOf ('PGvararray (null 'PGdate)) where oidOf = LibPQ.Oid 1182
451+instance OidOf 'PGtime where oidOf = LibPQ.Oid 1083
452+instance OidOf ('PGfixarray ns (null 'PGtime)) where oidOf = LibPQ.Oid 1183
453+instance OidOf ('PGvararray (null 'PGtime)) where oidOf = LibPQ.Oid 1183
454+instance OidOf 'PGtimetz where oidOf = LibPQ.Oid 1266
455+instance OidOf ('PGfixarray ns (null 'PGtimetz)) where oidOf = LibPQ.Oid 1270
456+instance OidOf ('PGvararray (null 'PGtimetz)) where oidOf = LibPQ.Oid 1270
457+instance OidOf 'PGinterval where oidOf = LibPQ.Oid 1186
458+instance OidOf ('PGfixarray ns (null 'PGinterval)) where oidOf = LibPQ.Oid 1187
459+instance OidOf ('PGvararray (null 'PGinterval)) where oidOf = LibPQ.Oid 1187
460+instance OidOf 'PGuuid where oidOf = LibPQ.Oid 2950
461+instance OidOf ('PGfixarray ns (null 'PGuuid)) where oidOf = LibPQ.Oid 2951
462+instance OidOf ('PGvararray (null 'PGuuid)) where oidOf = LibPQ.Oid 2951
463+instance OidOf 'PGinet where oidOf = LibPQ.Oid 869
464+instance OidOf ('PGfixarray ns (null 'PGinet)) where oidOf = LibPQ.Oid 1041
465+instance OidOf ('PGvararray (null 'PGinet)) where oidOf = LibPQ.Oid 1041
466+instance OidOf 'PGjson where oidOf = LibPQ.Oid 114
467+instance OidOf ('PGfixarray ns (null 'PGjson)) where oidOf = LibPQ.Oid 199
468+instance OidOf ('PGvararray (null 'PGjson)) where oidOf = LibPQ.Oid 199
469+instance OidOf 'PGjsonb where oidOf = LibPQ.Oid 3802
470+instance OidOf ('PGfixarray ns (null 'PGjsonb)) where oidOf = LibPQ.Oid 3807
471+instance OidOf ('PGvararray (null 'PGjsonb)) where oidOf = LibPQ.Oid 3807
472+instance OidOf 'PGtsvector where oidOf = LibPQ.Oid 3614
473+instance OidOf ('PGfixarray ns (null 'PGtsvector)) where oidOf = LibPQ.Oid 3643
474+instance OidOf ('PGvararray (null 'PGtsvector)) where oidOf = LibPQ.Oid 3643
475+instance OidOf 'PGtsquery where oidOf = LibPQ.Oid 3615
476+instance OidOf ('PGfixarray ns (null 'PGtsquery)) where oidOf = LibPQ.Oid 3645
477+instance OidOf ('PGvararray (null 'PGtsquery)) where oidOf = LibPQ.Oid 3645
478+instance OidOf 'PGoid where oidOf = LibPQ.Oid 26
479+instance OidOf ('PGfixarray ns (null 'PGoid)) where oidOf = LibPQ.Oid 1028
480+instance OidOf ('PGvararray (null 'PGoid)) where oidOf = LibPQ.Oid 1028
481+instance OidOf ('PGrange 'PGint4) where oidOf = LibPQ.Oid 3904
482+instance OidOf ('PGfixarray ns (null ('PGrange 'PGint4))) where oidOf = LibPQ.Oid 3905
483+instance OidOf ('PGvararray (null ('PGrange 'PGint4))) where oidOf = LibPQ.Oid 3905
484+instance OidOf ('PGrange 'PGint8) where oidOf = LibPQ.Oid 3926
485+instance OidOf ('PGfixarray ns (null ('PGrange 'PGint8))) where oidOf = LibPQ.Oid 3927
486+instance OidOf ('PGvararray (null ('PGrange 'PGint8))) where oidOf = LibPQ.Oid 3927
487+instance OidOf ('PGrange 'PGnumeric) where oidOf = LibPQ.Oid 3906
488+instance OidOf ('PGfixarray ns (null ('PGrange 'PGnumeric))) where oidOf = LibPQ.Oid 3907
489+instance OidOf ('PGvararray (null ('PGrange 'PGnumeric))) where oidOf = LibPQ.Oid 3907
490+instance OidOf ('PGrange 'PGtimestamp) where oidOf = LibPQ.Oid 3908
491+instance OidOf ('PGfixarray ns (null ('PGrange 'PGtimestamp))) where oidOf = LibPQ.Oid 3909
492+instance OidOf ('PGvararray (null ('PGrange 'PGtimestamp))) where oidOf = LibPQ.Oid 3909
493+instance OidOf ('PGrange 'PGtimestamptz) where oidOf = LibPQ.Oid 3910
494+instance OidOf ('PGfixarray ns (null ('PGrange 'PGtimestamptz))) where oidOf = LibPQ.Oid 3911
495+instance OidOf ('PGvararray (null ('PGrange 'PGtimestamptz))) where oidOf = LibPQ.Oid 3911
496+instance OidOf ('PGrange 'PGdate) where oidOf = LibPQ.Oid 3912
497+instance OidOf ('PGfixarray ns (null ('PGrange 'PGdate))) where oidOf = LibPQ.Oid 3913
498+instance OidOf ('PGvararray (null ('PGrange 'PGdate))) where oidOf = LibPQ.Oid 3913
499+instance {-# OVERLAPPABLE #-} OidOf ('PGrange ty) where oidOf = LibPQ.invalidOid
500+instance {-# OVERLAPPABLE #-} OidOf ('PGfixarray ns (null ('PGrange ty))) where oidOf = LibPQ.invalidOid
501+instance {-# OVERLAPPABLE #-} OidOf ('PGvararray (null ('PGrange ty))) where oidOf = LibPQ.invalidOid
502+instance {-# OVERLAPPABLE #-} OidOf ('PGcomposite row) where oidOf = LibPQ.invalidOid
503+instance {-# OVERLAPPABLE #-} OidOf ('PGfixarray ns (null ('PGcomposite row))) where oidOf = LibPQ.invalidOid
504+instance {-# OVERLAPPABLE #-} OidOf ('PGvararray (null ('PGcomposite row))) where oidOf = LibPQ.invalidOid
505+instance {-# OVERLAPPABLE #-} OidOf ('PGenum labels) where oidOf = LibPQ.invalidOid
506+instance {-# OVERLAPPABLE #-} OidOf ('PGfixarray ns (null ('PGenum labels))) where oidOf = LibPQ.invalidOid
507+instance {-# OVERLAPPABLE #-} OidOf ('PGvararray (null ('PGenum labels))) where oidOf = LibPQ.invalidOid
508+
509+class OidOfParam (ty :: NullityType) where oidOfParam :: Oid
510+instance OidOf ty => OidOfParam (null ty) where oidOfParam = oidOf @ty
511+
512+-- | Lifts a `OidOf` constraint to a field.
513+class OidOfField (field :: (Symbol, NullityType)) where
514+ oidOfField :: Oid
515+instance OidOf ty => OidOfField (alias ::: nullity ty) where
516+ oidOfField = oidOf @ty
517+
518+-- | A `ToNullityParam` constraint gives an encoding of a Haskell `Type` into
519+-- into the binary format of a PostgreSQL `NullityType`.
520+class ToNullityParam (x :: Type) (ty :: NullityType) where
521+ toNullityParam :: x -> K (Maybe Encoding.Encoding) ty
522+instance ToParam x pg => ToNullityParam x ('NotNull pg) where
523+ toNullityParam = K . Just . unK . toParam @x @pg
524+instance ToParam x pg => ToNullityParam (Maybe x) ('Null pg) where
525+ toNullityParam = K . fmap (unK . toParam @x @pg)
526+
527+-- | A `ToField` constraint lifts the `ToParam` parser
528+-- to an encoding of a @(Symbol, Type)@ to a @(Symbol, NullityType)@,
529+-- encoding `Null`s to `Maybe`s. You should not define instances for
530+-- `FromField`, just use the provided instances.
531+class ToField (x :: (Symbol, Type)) (field :: (Symbol, NullityType)) where
532+ toField :: P x -> K (Maybe Encoding.Encoding) field
533+instance ToNullityParam x ty => ToField (alias ::: x) (alias ::: ty) where
534+ toField (P x) = K . unK $ toNullityParam @x @ty x
535+
536+-- | A `ToFixArray` constraint gives an encoding of a Haskell `Type`
537+-- into the binary format of a PostgreSQL fixed-length array.
538+-- You should not define instances for
539+-- `ToFixArray`, just use the provided instances.
540+class ToFixArray (x :: Type) (dims :: [Nat]) (array :: NullityType) where
541+ toFixArray :: x -> K (K Encoding.Array dims) array
542+instance ToNullityParam x ty => ToFixArray x '[] ty where
543+ toFixArray = K . K . maybe Encoding.nullArray Encoding.encodingArray . unK
544+ . toNullityParam @x @ty
545+instance
546+ ( IsProductType product xs
547+ , Length xs ~ dim
548+ , All ((~) x) xs
549+ , ToFixArray x dims ty )
550+ => ToFixArray product (dim ': dims) ty where
551+ toFixArray = K . K . Encoding.dimensionArray foldlN
552+ (unK . unK . toFixArray @x @dims @ty) . unZ . unSOP . from
134553
135554-- | A `ToParams` constraint generically sequences the encodings of `Type`s
136555-- of the fields of a tuple or record to a row of `ColumnType`s. You should
137−-- not define instances of `ToParams`. Instead define `Generic` instances
556+-- not define instances of `ToParams`. Instead define `SOP.Generic` instances
138557-- which in turn provide `ToParams` instances.
139558class SListI tys => ToParams (x :: Type) (tys :: [NullityType]) where
140559 -- | >>> type Params = '[ 'NotNull 'PGbool, 'Null 'PGint2]
141560 -- >>> toParams @(Bool, Maybe Int16) @'[ 'NotNull 'PGbool, 'Null 'PGint2] (False, Just 0)
142− -- K (Just "\NUL") :* (K (Just "\NUL\NUL") :* Nil)
561+ -- K (Just "\NUL") :* K (Just "\NUL\NUL") :* Nil
143562 --
144563 -- >>> :set -XDeriveGeneric
145564 -- >>> data Tuple = Tuple { p1 :: Bool, p2 :: Maybe Int16} deriving GHC.Generic
146565 -- >>> instance Generic Tuple
147566 -- >>> toParams @Tuple @Params (Tuple False (Just 0))
148− -- K (Just "\NUL") :* (K (Just "\NUL\NUL") :* Nil)
149− toParams :: x -> NP (K (Maybe Strict.ByteString)) tys
150−instance (SListI tys, IsProductType x xs, AllZip ToColumnParam xs tys)
567+ -- K (Just "\NUL") :* K (Just "\NUL\NUL") :* Nil
568+ toParams :: x -> NP (K (Maybe Encoding.Encoding)) tys
569+instance (SListI tys, IsProductType x xs, AllZip ToNullityParam xs tys)
151570 => ToParams x tys where
152571 toParams
153− = htrans (Proxy @ToColumnParam) (toColumnParam . unI)
572+ = htrans (Proxy @ToNullityParam) (toNullityParam . unI)
154573 . unZ . unSOP . from
155574
156575-- | A `FromValue` constraint gives a parser from the binary format of
157576-- a PostgreSQL `PGType` into a Haskell `Type`.
158577class FromValue (pg :: PGType) (y :: Type) where
159578 -- | >>> newtype Id = Id { getId :: Int16 } deriving Show
160− -- >>> instance FromValue 'PGint2 Id where fromValue = fmap Id . fromValue
161− fromValue :: proxy pg -> Decoding.Value y
162−instance FromValue 'PGbool Bool where fromValue _ = Decoding.bool
163−instance FromValue 'PGint2 Int16 where fromValue _ = Decoding.int
164−instance FromValue 'PGint4 Int32 where fromValue _ = Decoding.int
165−instance FromValue 'PGint8 Int64 where fromValue _ = Decoding.int
166−instance FromValue 'PGfloat4 Float where fromValue _ = Decoding.float4
167−instance FromValue 'PGfloat8 Double where fromValue _ = Decoding.float8
168−instance FromValue 'PGnumeric Scientific where fromValue _ = Decoding.numeric
169−instance FromValue 'PGuuid UUID where fromValue _ = Decoding.uuid
170−instance FromValue 'PGinet (NetAddr IP) where fromValue _ = Decoding.inet
171−instance FromValue ('PGchar 1) Char where fromValue _ = Decoding.char
172−instance FromValue 'PGtext Strict.Text where fromValue _ = Decoding.text_strict
173−instance FromValue 'PGtext Lazy.Text where fromValue _ = Decoding.text_lazy
579+ -- >>> instance FromValue 'PGint2 Id where fromValue = Id <$> fromValue @'PGint2
580+ fromValue :: Decoding.Value y
581+instance FromValue 'PGbool Bool where fromValue = Decoding.bool
582+instance FromValue 'PGint2 Int16 where fromValue = Decoding.int
583+instance FromValue 'PGint4 Int32 where fromValue = Decoding.int
584+instance FromValue 'PGint8 Int64 where fromValue = Decoding.int
585+instance FromValue 'PGoid Word32 where fromValue = Decoding.int
586+instance FromValue 'PGfloat4 Float where fromValue = Decoding.float4
587+instance FromValue 'PGfloat8 Double where fromValue = Decoding.float8
588+instance FromValue 'PGnumeric Scientific where fromValue = Decoding.numeric
589+instance FromValue 'PGmoney Money where fromValue = Money <$> Decoding.int
590+instance FromValue 'PGuuid UUID where fromValue = Decoding.uuid
591+instance FromValue 'PGinet (NetAddr IP) where fromValue = Decoding.inet
592+instance FromValue ('PGchar 1) Char where fromValue = Decoding.char
593+instance FromValue 'PGtext Strict.Text where fromValue = Decoding.text_strict
594+instance FromValue 'PGtext Lazy.Text where fromValue = Decoding.text_lazy
595+instance FromValue 'PGtext String where
596+ fromValue = Strict.Text.unpack <$> Decoding.text_strict
174597instance FromValue 'PGbytea Strict.ByteString where
175− fromValue _ = Decoding.bytea_strict
598+ fromValue = Decoding.bytea_strict
176599instance FromValue 'PGbytea Lazy.ByteString where
177− fromValue _ = Decoding.bytea_lazy
178−instance FromValue 'PGdate Day where fromValue _ = Decoding.date
179−instance FromValue 'PGtime TimeOfDay where fromValue _ = Decoding.time_int
600+ fromValue = Decoding.bytea_lazy
601+instance FromValue 'PGdate Day where fromValue = Decoding.date
602+instance FromValue 'PGtime TimeOfDay where fromValue = Decoding.time_int
180603instance FromValue 'PGtimetz (TimeOfDay, TimeZone) where
181− fromValue _ = Decoding.timetz_int
604+ fromValue = Decoding.timetz_int
182605instance FromValue 'PGtimestamp LocalTime where
183− fromValue _ = Decoding.timestamp_int
606+ fromValue = Decoding.timestamp_int
184607instance FromValue 'PGtimestamptz UTCTime where
185− fromValue _ = Decoding.timestamptz_int
608+ fromValue = Decoding.timestamptz_int
186609instance FromValue 'PGinterval DiffTime where
187− fromValue _ = Decoding.interval_int
188−instance FromValue 'PGjson Value where fromValue _ = Decoding.json_ast
189−instance FromValue 'PGjsonb Value where fromValue _ = Decoding.jsonb_ast
610+ fromValue = Decoding.interval_int
611+instance FromValue 'PGjson Aeson.Value where fromValue = Decoding.json_ast
612+instance FromValue 'PGjsonb Aeson.Value where fromValue = Decoding.jsonb_ast
613+instance Aeson.FromJSON x => FromValue 'PGjson (Json x) where
614+ fromValue = Json <$>
615+ Decoding.json_bytes (left Strict.Text.pack . Aeson.eitherDecodeStrict)
616+instance Aeson.FromJSON x => FromValue 'PGjsonb (Jsonb x) where
617+ fromValue = Jsonb <$>
618+ Decoding.jsonb_bytes (left Strict.Text.pack . Aeson.eitherDecodeStrict)
619+instance FromValue pg y
620+ => FromValue ('PGvararray ('NotNull pg)) (VarArray (Vector y)) where
621+ fromValue =
622+ let
623+ rep n x = VarArray <$> Vector.replicateM n x
624+ in
625+ Decoding.array $ Decoding.dimensionArray rep
626+ (fromFixArray @'[] @('NotNull pg))
627+instance FromValue pg y
628+ => FromValue ('PGvararray ('Null pg)) (VarArray (Vector (Maybe y))) where
629+ fromValue =
630+ let
631+ rep n x = VarArray <$> Vector.replicateM n x
632+ in
633+ Decoding.array $ Decoding.dimensionArray rep
634+ (fromFixArray @'[] @('Null pg))
635+instance FromValue pg y
636+ => FromValue ('PGvararray ('NotNull pg)) (VarArray [y]) where
637+ fromValue =
638+ let
639+ rep n x = VarArray <$> replicateM n x
640+ in
641+ Decoding.array $ Decoding.dimensionArray rep
642+ (fromFixArray @'[] @('NotNull pg))
643+instance FromValue pg y
644+ => FromValue ('PGvararray ('Null pg)) (VarArray [Maybe y]) where
645+ fromValue =
646+ let
647+ rep n x = VarArray <$> replicateM n x
648+ in
649+ Decoding.array $ Decoding.dimensionArray rep
650+ (fromFixArray @'[] @('Null pg))
651+instance FromFixArray dims ty y
652+ => FromValue ('PGfixarray dims ty) (FixArray y) where
653+ fromValue = FixArray <$> Decoding.array (fromFixArray @dims @ty @y)
654+instance
655+ ( IsEnumType y
656+ , HasDatatypeInfo y
657+ , LabelsPG y ~ labels
658+ ) => FromValue ('PGenum labels) (Enumerated y) where
659+ fromValue =
660+ let
661+ greadConstructor
662+ :: All ((~) '[]) xss
663+ => NP ConstructorInfo xss
664+ -> String
665+ -> Maybe (SOP I xss)
666+ greadConstructor Nil _ = Nothing
667+ greadConstructor (constructor :* constructors) name =
668+ if name == constructorName constructor
669+ then Just (SOP (Z Nil))
670+ else SOP . S . unSOP <$> greadConstructor constructors name
671+ in
672+ fmap Enumerated
673+ . Decoding.enum
674+ $ fmap to
675+ . greadConstructor (constructorInfo (datatypeInfo (Proxy @y)))
676+ . Strict.Text.unpack
677+instance
678+ ( FromRow fields y
679+ ) => FromValue ('PGcomposite fields) (Composite y) where
680+ fromValue =
681+ let
682+ -- <number of fields: 4 bytes>
683+ -- [for each field]
684+ -- <OID of field's type: sizeof(Oid) bytes>
685+ -- [if value is NULL]
686+ -- <-1: 4 bytes>
687+ -- [else]
688+ -- <length of value: 4 bytes>
689+ -- <value: <length> bytes>
690+ -- [end if]
691+ -- [end for]
692+ composite = Decoding.valueParser $ do
693+ unitOfSize 4
694+ hsequence' $ hpure $ Comp $ do
695+ unitOfSize 4
696+ len <- sized 4 Decoding.int
697+ if len == -1
698+ then return (K Nothing)
699+ else K . Just <$> bytesOfSize len
700+ in
701+ fmap Composite (Decoding.fn (fromRow @fields <=< composite))
190702
191−-- | A `FromColumnValue` constraint lifts the `FromValue` parser
192−-- to a decoding of a @(Symbol, ColumnType)@ to a `Type`,
703+-- | A `FromField` constraint lifts the `FromValue` parser
704+-- to a decoding of a @(Symbol, NullityType)@ to a `Type`,
193705-- decoding `Null`s to `Maybe`s. You should not define instances for
194−-- `FromColumnValue`, just use the provided instances.
195−class FromColumnValue (colty :: (Symbol,NullityType)) (y :: Type) where
196− -- | >>> :set -XTypeOperators -XOverloadedStrings
197− -- >>> newtype Id = Id { getId :: Int16 } deriving Show
198− -- >>> instance FromValue 'PGint2 Id where fromValue = fmap Id . fromValue
199− -- >>> fromColumnValue @("col" ::: 'NotNull 'PGint2) @Id (K (Just "\NUL\SOH"))
200− -- Id {getId = 1}
201− --
202− -- >>> fromColumnValue @("col" ::: 'Null 'PGint2) @(Maybe Id) (K (Just "\NUL\SOH"))
203− -- Just (Id {getId = 1})
204− fromColumnValue :: K (Maybe Strict.ByteString) colty -> y
706+-- `FromField`, just use the provided instances.
707+class FromField (pg :: (Symbol, NullityType)) (y :: (Symbol, Type)) where
708+ fromField
709+ :: K (Maybe Strict.ByteString) pg
710+ -> (Either Strict.Text :.: P) y
205711instance FromValue pg y
206− => FromColumnValue (column ::: ('NotNull pg)) y where
207− fromColumnValue = \case
208− K Nothing -> error "fromColumnValue: saw NULL when expecting NOT NULL"
209− K (Just bytes) ->
210− let
211− errOrValue =
212− Decoding.valueParser (fromValue @pg @y Proxy) bytes
213− err str = error $ "fromColumnValue: " ++ Strict.unpack str
214− in
215− either err id errOrValue
712+ => FromField (column ::: ('NotNull pg)) (column ::: y) where
713+ fromField = Comp . \case
714+ K Nothing -> Left "fromField: saw NULL when expecting NOT NULL"
715+ K (Just bytestring) -> P <$>
716+ Decoding.valueParser (fromValue @pg) bytestring
216717instance FromValue pg y
217− => FromColumnValue (column ::: ('Null pg)) (Maybe y) where
218− fromColumnValue (K nullOrBytes)
219− = either err id
220− . Decoding.valueParser (fromValue @pg @y Proxy)
221− <$> nullOrBytes
222− where
223− err str = error $ "fromColumnValue: " ++ Strict.unpack str
718+ => FromField (column ::: 'Null pg) (column ::: Maybe y) where
719+ fromField = Comp . \case
720+ K Nothing -> Right $ P Nothing
721+ K (Just bytestring) -> P . Just <$>
722+ Decoding.valueParser (fromValue @pg) bytestring
723+
724+-- | A `FromFixArray` constraint gives a decoding to a Haskell `Type`
725+-- from the binary format of a PostgreSQL fixed-length array.
726+-- You should not define instances for
727+-- `FromFixArray`, just use the provided instances.
728+class FromFixArray (dims :: [Nat]) (ty :: NullityType) (y :: Type) where
729+ fromFixArray :: Decoding.Array y
730+instance FromValue pg y => FromFixArray '[] ('NotNull pg) y where
731+ fromFixArray = Decoding.valueArray (fromValue @pg @y)
732+instance FromValue pg y => FromFixArray '[] ('Null pg) (Maybe y) where
733+ fromFixArray = Decoding.nullableValueArray (fromValue @pg @y)
734+instance
735+ ( IsProductType product ys
736+ , Length ys ~ dim
737+ , All ((~) y) ys
738+ , FromFixArray dims ty y )
739+ => FromFixArray (dim ': dims) ty product where
740+ fromFixArray =
741+ let
742+ rep _ = fmap (to . SOP . Z) . replicateMN
743+ in
744+ Decoding.dimensionArray rep (fromFixArray @dims @ty @y)
224745
225746-- | A `FromRow` constraint generically sequences the parsings of the columns
226−-- of a `ColumnsType` into the fields of a record `Type` provided they have
747+-- of a `RowType` into the fields of a record `Type` provided they have
227748-- the same field names. You should not define instances of `FromRow`.
228−-- Instead define `Generic` and `HasDatatypeInfo` instances which in turn
749+-- Instead define `SOP.Generic` and `SOP.HasDatatypeInfo` instances which in turn
229750-- provide `FromRow` instances.
230−class SListI results => FromRow (results :: RelationType) y where
751+class SListI result => FromRow (result :: RowType) y where
231752 -- | >>> :set -XOverloadedStrings
232753 -- >>> import Data.Text
233754 -- >>> newtype UserId = UserId { getUserId :: Int16 } deriving Show
234− -- >>> instance FromValue 'PGint2 UserId where fromValue = fmap UserId . fromValue
755+ -- >>> instance FromValue 'PGint2 UserId where fromValue = UserId <$> fromValue @'PGint2
235756 -- >>> data UserRow = UserRow { userId :: UserId, userName :: Maybe Text } deriving (Show, GHC.Generic)
236757 -- >>> instance Generic UserRow
237758 -- >>> instance HasDatatypeInfo UserRow
238759 -- >>> type User = '["userId" ::: 'NotNull 'PGint2, "userName" ::: 'Null 'PGtext]
239760 -- >>> fromRow @User @UserRow (K (Just "\NUL\SOH") :* K (Just "bloodninja") :* Nil)
240− -- UserRow {userId = UserId {getUserId = 1}, userName = Just "bloodninja"}
241− fromRow :: NP (K (Maybe Strict.ByteString)) results -> y
761+ -- Right (UserRow {userId = UserId {getUserId = 1}, userName = Just "bloodninja"})
762+ fromRow :: NP (K (Maybe Strict.ByteString)) result -> Either Strict.Text y
242763instance
243− ( SListI results
244− , IsProductType y ys
245− , AllZip FromColumnValue results ys
246− , SameFields (DatatypeInfoOf y) results
247− ) => FromRow results y where
764+ ( SListI result
765+ , IsRecord y ys
766+ , AllZip FromField result ys
767+ ) => FromRow result y where
248768 fromRow
249− = to . SOP . Z . htrans (Proxy @FromColumnValue) (I . fromColumnValue)
769+ = fmap fromRecord
770+ . hsequence'
771+ . htrans (Proxy @FromField) fromField
772+------------------------------------------------------
773+-- P records
774+------------------------------------------------------
775+-- instance (FromField (col ::: pg) (col ::: hask))
776+-- => FromRow '[col ::: pg] (P (col ::: hask)) where
777+-- fromRow (pg :* Nil) = (unComp . fromField) pg
778+-- instance
779+-- ( row ~ Join row1 row2
780+-- , FromRow row1 hask1
781+-- , FromRow row2 hask2
782+-- , SListI row
783+-- ) => FromRow row (hask1, hask2) where
784+-- fromRow row = case disjoin @row1 @row2 row of
785+-- (row1, row2) -> (,) <$> fromRow row1 <*> fromRow row2
786+-- instance
787+-- ( row ~ Join row1 row23
788+-- , FromRow row1 hask1
789+-- , FromRow row23 (hask2, hask3)
790+-- , SListI row
791+-- ) => FromRow row (hask1, hask2, hask3) where
792+-- fromRow row = case disjoin @row1 @row23 row of
793+-- (row1, row23) -> do
794+-- hask1 <- fromRow row1
795+-- (hask2, hask3) <- fromRow row23
796+-- return (hask1, hask2, hask3)
797+-- instance
798+-- ( row ~ Join row1 row234
799+-- , FromRow row1 hask1
800+-- , FromRow row234 (hask2, hask3, hask4)
801+-- , SListI row
802+-- ) => FromRow row (hask1, hask2, hask3, hask4) where
803+-- fromRow row = case disjoin @row1 @row234 row of
804+-- (row1, row234) -> do
805+-- hask1 <- fromRow row1
806+-- (hask2, hask3, hask4) <- fromRow row234
807+-- return (hask1, hask2, hask3, hask4)
808+-- instance
809+-- ( row ~ Join row1 row2345
810+-- , FromRow row1 hask1
811+-- , FromRow row2345 (hask2, hask3, hask4, hask5)
812+-- , SListI row
813+-- ) => FromRow row (hask1, hask2, hask3, hask4, hask5) where
814+-- fromRow row = case disjoin @row1 @row2345 row of
815+-- (row1, row2345) -> do
816+-- hask1 <- fromRow row1
817+-- (hask2, hask3, hask4, hask5) <- fromRow row2345
818+-- return (hask1, hask2, hask3, hask4, hask5)
250819
251820-- | `Only` is a 1-tuple type, useful for encoding a single parameter with
252821-- `toParams` or decoding a single value with `fromRow`.
@@ -256,8 +825,24 @@ instance
256825-- K (Just "foo") :* Nil
257826--
258827-- >>> fromRow @'["fromOnly" ::: 'Null 'PGtext] @(Only (Maybe Text)) (K (Just "bar") :* Nil)
259−-- Only {fromOnly = Just "bar"}
828+-- Right (Only {fromOnly = Just "bar"})
260829newtype Only x = Only { fromOnly :: x }
261830 deriving (Functor,Foldable,Traversable,Eq,Ord,Read,Show,GHC.Generic)
262831instance Generic (Only x)
263832instance HasDatatypeInfo (Only x)
833+
834+foldlN
835+ :: All ((~) x) xs
836+ => (z -> x -> z) -> z -> NP I xs -> z
837+foldlN f z = \case
838+ Nil -> z
839+ I x :* xs -> let z' = f z x in seq z' $ foldlN f z' xs
840+
841+replicateMN
842+ :: forall x xs m. (All ((~) x) xs, Monad m, SListI xs)
843+ => m x -> m (NP I xs)
844+replicateMN mx = hsequence' $
845+ hcpure (Proxy :: Proxy ((~) x)) (Comp (I <$> mx))
846+
847+getOid :: LibPQ.Oid -> Word32
848+getOid (LibPQ.Oid (CUInt oid)) = oid
squeal-postgresql/src/Squeal/PostgreSQL/Definition.hs+30−570
@@ -9,614 +9,74 @@ Squeal data definition language.
99-}
1010
1111{-# LANGUAGE
12− DataKinds
13− , DeriveDataTypeable
12+ AllowAmbiguousTypes
13+ , ConstraintKinds
14+ , DeriveAnyClass
1415 , DeriveGeneric
16+ , DerivingStrategies
1517 , FlexibleContexts
1618 , FlexibleInstances
1719 , GADTs
18− , GeneralizedNewtypeDeriving
19− , KindSignatures
2020 , LambdaCase
2121 , MultiParamTypeClasses
22+ , OverloadedLabels
2223 , OverloadedStrings
2324 , RankNTypes
2425 , ScopedTypeVariables
25− , StandaloneDeriving
2626 , TypeApplications
2727 , TypeInType
2828 , TypeOperators
29+ , UndecidableSuperClasses
30+ , UndecidableInstances
2931#-}
3032
3133module Squeal.PostgreSQL.Definition
32− ( -- * Definition
33− Definition (UnsafeDefinition, renderDefinition)
34+ ( -- * Definition
35+ Definition (..)
3436 , (>>>)
35− -- * Create
36− , createTable
37− , TableConstraintExpression (..)
38− , Column (..)
39− , check
40− , unique
41− , primaryKey
42− , foreignKey
43− , OnDeleteClause (OnDeleteNoAction, OnDeleteRestrict, OnDeleteCascade)
44− , renderOnDeleteClause
45− , OnUpdateClause (OnUpdateNoAction, OnUpdateRestrict, OnUpdateCascade)
46− , renderOnUpdateClause
47− -- * Drop
48− , dropTable
49− -- * Alter
50− , alterTable
51− , alterTableRename
52− , addConstraint
53− , dropConstraint
54− , AlterTable (UnsafeAlterTable, renderAlterTable)
55− , addColumnDefault
56− , addColumnNull
57− , dropColumn
58− -- , dropColumnCascade
59− , renameColumn
60− , alterColumn
61− , AlterColumn (UnsafeAlterColumn, renderAlterColumn)
62− , setDefault
63− , dropDefault
64− , setNotNull
65− , dropNotNull
66− , alterType
37+ , manipDefinition
6738 ) where
6839
6940import Control.Category
7041import Control.DeepSeq
7142import Data.ByteString
7243import Data.Monoid
73−import GHC.TypeLits
7444import Prelude hiding ((.), id)
7545
76−import qualified Generics.SOP as SOP
7746import qualified GHC.Generics as GHC
7847
79−import Squeal.PostgreSQL.Expression
80−import Squeal.PostgreSQL.Prettyprint
48+import Squeal.PostgreSQL.Manipulation
49+import Squeal.PostgreSQL.Render
8150import Squeal.PostgreSQL.Schema
8251
52+-- $setup
53+-- >>> import Squeal.PostgreSQL
54+
8355{-----------------------------------------
8456statements
8557-----------------------------------------}
8658
87−-- | A `Definition` is a statement that changes the schema of the
59+-- | A `Definition` is a statement that changes the schemas of the
8860-- database, like a `createTable`, `dropTable`, or `alterTable` command.
8961-- `Definition`s may be composed using the `>>>` operator.
9062newtype Definition
91− (schema0 :: TablesType)
92− (schema1 :: TablesType)
63+ (schemas0 :: SchemasType)
64+ (schemas1 :: SchemasType)
9365 = UnsafeDefinition { renderDefinition :: ByteString }
9466 deriving (GHC.Generic,Show,Eq,Ord,NFData)
9567
68+instance RenderSQL (Definition schemas0 schemas1) where
69+ renderSQL = renderDefinition
70+
9671instance Category Definition where
9772 id = UnsafeDefinition ";"
9873 ddl1 . ddl0 = UnsafeDefinition $
99− renderDefinition ddl0 <+> renderDefinition ddl1
100−
101−{-----------------------------------------
102−CREATE statements
103−-----------------------------------------}
104−
105−-- | `createTable` adds a table to the schema.
106−--
107−-- >>> :set -XOverloadedLabels
108−-- >>> :{
109−-- renderDefinition $
110−-- createTable #tab (int `As` #a :* real `As` #b :* Nil) Nil
111−-- :}
112−-- "CREATE TABLE tab (a int, b real);"
113−createTable
114− :: ( KnownSymbol table
115− , columns ~ (col ': cols)
116− , SOP.SListI columns
117− , SOP.SListI constraints )
118− => Alias table -- ^ the name of the table to add
119− -> NP (Aliased TypeExpression) columns
120− -- ^ the names and datatype of each column
121− -> NP (Aliased (TableConstraintExpression schema columns)) constraints
122− -- ^ constraints that must hold for the table
123− -> Definition schema (Create table (constraints :=> columns) schema)
124−createTable table columns constraints = UnsafeDefinition $
125− "CREATE TABLE" <+> renderAlias table
126− <+> parenthesized
127− ( renderCommaSeparated renderColumnDef columns
128− <> ( case constraints of
129− Nil -> ""
130− _ -> ", " <>
131− renderCommaSeparated renderConstraint constraints ) )
132− <> ";"
133− where
134− renderColumnDef :: Aliased TypeExpression x -> ByteString
135− renderColumnDef (ty `As` column) =
136− renderAlias column <+> renderTypeExpression ty
137− renderConstraint
138− :: Aliased (TableConstraintExpression schema columns) constraint
139− -> ByteString
140− renderConstraint (constraint `As` alias) =
141− "CONSTRAINT" <+> renderAlias alias <+> renderTableConstraintExpression constraint
142−
143−-- | Data types are a way to limit the kind of data that can be stored in a
144−-- table. For many applications, however, the constraint they provide is
145−-- too coarse. For example, a column containing a product price should
146−-- probably only accept positive values. But there is no standard data type
147−-- that accepts only positive numbers. Another issue is that you might want
148−-- to constrain column data with respect to other columns or rows.
149−-- For example, in a table containing product information,
150−-- there should be only one row for each product number.
151−-- `TableConstraint`s give you as much control over the data in your tables
152−-- as you wish. If a user attempts to store data in a column that would
153−-- violate a constraint, an error is raised. This applies
154−-- even if the value came from the default value definition.
155−newtype TableConstraintExpression
156− (schema :: TablesType)
157− (columns :: ColumnsType)
158− (tableConstraint :: TableConstraint)
159− = UnsafeTableConstraintExpression
160− { renderTableConstraintExpression :: ByteString }
161− deriving (GHC.Generic,Show,Eq,Ord,NFData)
162−
163−data Column
164− (columns :: ColumnsType)
165− (column :: (Symbol,ColumnType))
166− where
167− Column
168− :: Has column columns ty
169− => Alias column
170− -> Column columns (column ::: ty)
171−
172−renderColumn :: Column columns column -> ByteString
173−renderColumn (Column column) = renderAlias column
174−
175−-- | A `check` constraint is the most generic `TableConstraint` type.
176−-- It allows you to specify that the value in a certain column must satisfy
177−-- a Boolean (truth-value) expression.
178−--
179−-- >>> :{
180−-- renderDefinition $
181−-- createTable #tab
182−-- ( (int & notNull) `As` #a :*
183−-- (int & notNull) `As` #b :* Nil )
184−-- ( check (#a .> #b) `As` #inequality :* Nil )
185−-- :}
186−-- "CREATE TABLE tab (a int NOT NULL, b int NOT NULL, CONSTRAINT inequality CHECK ((a > b)));"
187−check
188− :: Condition '[table ::: ColumnsToRelation columns] 'Ungrouped '[]
189− -- ^ condition to check
190− -> TableConstraintExpression schema columns 'Check
191−check condition = UnsafeTableConstraintExpression $
192− "CHECK" <+> parenthesized (renderExpression condition)
193−
194−-- | A `unique` constraint ensure that the data contained in a column,
195−-- or a group of columns, is unique among all the rows in the table.
196−--
197−-- >>> :{
198−-- renderDefinition $
199−-- createTable #tab
200−-- ( int `As` #a :*
201−-- int `As` #b :* Nil )
202−-- ( unique (Column #a :* Column #b :* Nil) `As` #uq_a_b :* Nil )
203−-- :}
204−-- "CREATE TABLE tab (a int, b int, CONSTRAINT uq_a_b UNIQUE (a, b));"
205−unique
206− :: SOP.SListI subcolumns
207− => NP (Column columns) subcolumns
208− -- ^ unique column or group of columns
209− -> TableConstraintExpression schema columns ('Unique (AliasesOf subcolumns))
210−unique columns = UnsafeTableConstraintExpression $
211− "UNIQUE" <+> parenthesized (renderCommaSeparated renderColumn columns)
212−
213−-- | A `primaryKey` constraint indicates that a column, or group of columns,
214−-- can be used as a unique identifier for rows in the table.
215−-- This requires that the values be both unique and not null.
216−--
217−-- >>> :{
218−-- renderDefinition $
219−-- createTable #tab
220−-- ( serial `As` #id :*
221−-- (text & notNull) `As` #name :* Nil )
222−-- ( primaryKey (Column #id :* Nil) `As` #pk_id :* Nil )
223−-- :}
224−-- "CREATE TABLE tab (id serial, name text NOT NULL, CONSTRAINT pk_id PRIMARY KEY (id));"
225−primaryKey
226− :: (SOP.SListI subcolumns, AllNotNull subcolumns)
227− => NP (Column columns) subcolumns
228− -- ^ identifying column or group of columns
229− -> TableConstraintExpression schema columns ('PrimaryKey (AliasesOf subcolumns))
230−primaryKey columns = UnsafeTableConstraintExpression $
231− "PRIMARY KEY" <+> parenthesized (renderCommaSeparated renderColumn columns)
232−
233−-- | A `foreignKey` specifies that the values in a column
234−-- (or a group of columns) must match the values appearing in some row of
235−-- another table. We say this maintains the referential integrity
236−-- between two related tables.
237−--
238−-- >>> :{
239−-- type Schema =
240−-- '[ "users" :::
241−-- '[ "pk_id" ::: 'PrimaryKey '["id"] ] :=>
242−-- '[ "id" ::: 'Def :=> 'NotNull 'PGint4
243−-- , "name" ::: 'NoDef :=> 'NotNull 'PGtext
244−-- ]
245−-- , "emails" :::
246−-- '[ "pk_id" ::: 'PrimaryKey '["id"]
247−-- , "fk_user_id" ::: 'ForeignKey '["user_id"] "users" '["id"]
248−-- ] :=>
249−-- '[ "id" ::: 'Def :=> 'NotNull 'PGint4
250−-- , "user_id" ::: 'NoDef :=> 'NotNull 'PGint4
251−-- , "email" ::: 'NoDef :=> 'Null 'PGtext
252−-- ]
253−-- ]
254−-- :}
255−--
256−-- :{
257−-- let
258−-- setup :: Definition '[] Schema
259−-- setup =
260−-- createTable #users
261−-- ( #id serial :*
262−-- #name (text & notNull) :* Nil )
263−-- ( #pk_id (primaryKey (Column #id :* Nil)) :* Nil ) >>>
264−-- createTable #emails
265−-- ( #id serial :*
266−-- #user_id (int & notNull) :*
267−-- #email text :* Nil )
268−-- ( #pk_id (primaryKey (Column #id :* Nil)) :*
269−-- #fk_user_id (foreignKey (Column #user_id :* Nil) #users (Column #id :* Nil)
270−-- OnDeleteCascade OnUpdateCascade) :* Nil )
271−-- in renderDefinition setup
272−-- :}
273−-- "CREATE TABLE users (id serial, username text NOT NULL, CONSTRAINT pk_id PRIMARY KEY (id)); CREATE TABLE emails (id serial, userid integer NOT NULL, email text NOT NULL, CONSTRAINT pk_id PRIMARY KEY (id), CONSTRAINT fk_user_id FOREIGN KEY (userid) REFERENCES users (id) ON DELETE CASCADE ON UPDATE RESTRICT);"
274−foreignKey
275− :: ( Has table schema reftable
276− , refcolumns ~ TableToColumns reftable
277− , SameTypes subcolumns refsubcolumns
278− , AllNotNull subcolumns
279− , SOP.SListI subcolumns
280− , SOP.SListI refsubcolumns)
281− => NP (Column columns) subcolumns
282− -- ^ column or columns in the table
283− -> Alias table
284− -- ^ reference table
285− -> NP (Column refcolumns) refsubcolumns
286− -- ^ reference column or columns in the reference table
287− -> OnDeleteClause
288− -- ^ what to do when reference is deleted
289− -> OnUpdateClause
290− -- ^ what to do when reference is updated
291− -> TableConstraintExpression schema columns
292− ('ForeignKey (AliasesOf subcolumns) table (AliasesOf refsubcolumns))
293−foreignKey columns reftable refcolumns onDelete onUpdate =
294− UnsafeTableConstraintExpression $
295− "FOREIGN KEY" <+> parenthesized (renderCommaSeparated renderColumn columns)
296− <+> "REFERENCES" <+> renderAlias reftable
297− <+> parenthesized (renderCommaSeparated renderColumn refcolumns)
298− <+> renderOnDeleteClause onDelete
299− <+> renderOnUpdateClause onUpdate
300−
301−-- | `OnDelete` indicates what to do with rows that reference a deleted row.
302−data OnDeleteClause
303− = OnDeleteNoAction
304− -- ^ if any referencing rows still exist when the constraint is checked,
305− -- an error is raised
306− | OnDeleteRestrict -- ^ prevents deletion of a referenced row
307− | OnDeleteCascade
308− -- ^ specifies that when a referenced row is deleted,
309− -- row(s) referencing it should be automatically deleted as well
310− deriving (GHC.Generic,Show,Eq,Ord)
311−instance NFData OnDeleteClause
312−
313−-- | Render `OnDeleteClause`.
314−renderOnDeleteClause :: OnDeleteClause -> ByteString
315−renderOnDeleteClause = \case
316− OnDeleteNoAction -> "ON DELETE NO ACTION"
317− OnDeleteRestrict -> "ON DELETE RESTRICT"
318− OnDeleteCascade -> "ON DELETE CASCADE"
319−
320−-- | Analagous to `OnDelete` there is also `OnUpdate` which is invoked
321−-- when a referenced column is changed (updated).
322−data OnUpdateClause
323− = OnUpdateNoAction
324− -- ^ if any referencing rows has not changed when the constraint is checked,
325− -- an error is raised
326− | OnUpdateRestrict -- ^ prevents update of a referenced row
327− | OnUpdateCascade
328− -- ^ the updated values of the referenced column(s) should be copied
329− -- into the referencing row(s)
330− deriving (GHC.Generic,Show,Eq,Ord)
331−instance NFData OnUpdateClause
332−
333−-- | Render `OnUpdateClause`.
334−renderOnUpdateClause :: OnUpdateClause -> ByteString
335−renderOnUpdateClause = \case
336− OnUpdateNoAction -> "ON UPDATE NO ACTION"
337− OnUpdateRestrict -> "ON UPDATE RESTRICT"
338− OnUpdateCascade -> "ON UPDATE CASCADE"
339−
340−{-----------------------------------------
341−DROP statements
342−-----------------------------------------}
343−
344−-- | `dropTable` removes a table from the schema.
345−--
346−-- >>> renderDefinition $ dropTable #muh_table
347−-- "DROP TABLE muh_table;"
348−dropTable
349− :: KnownSymbol table
350− => Alias table -- ^ table to remove
351− -> Definition schema (Drop table schema)
352−dropTable table = UnsafeDefinition $ "DROP TABLE" <+> renderAlias table <> ";"
353−
354−{-----------------------------------------
355−ALTER statements
356−-----------------------------------------}
357−
358−-- | `alterTable` changes the definition of a table from the schema.
359−alterTable
360− :: (KnownSymbol tab, (tab ::: table0) `In` schema)
361− => Alias tab -- ^ table to alter
362− -> AlterTable schema table0 table1 -- ^ alteration to perform
363− -> Definition schema (Alter tab schema table1)
364−alterTable table alteration = UnsafeDefinition $
365− "ALTER TABLE"
366− <+> renderAlias table
367− <+> renderAlterTable alteration
368− <> ";"
369−
370−-- | `alterTableRename` changes the name of a table from the schema.
371−--
372−-- >>> renderDefinition $ alterTableRename #foo #bar
373−-- "ALTER TABLE foo RENAME TO bar;"
374−alterTableRename
375− :: (KnownSymbol table0, KnownSymbol table1)
376− => Alias table0 -- ^ table to rename
377− -> Alias table1 -- ^ what to rename it
378− -> Definition schema (Rename table0 table1 schema)
379−alterTableRename table0 table1 = UnsafeDefinition $
380− "ALTER TABLE" <+> renderAlias table0
381− <+> "RENAME TO" <+> renderAlias table1 <> ";"
382−
383−-- | An `addConstraint` adds a table constraint.
384−--
385−-- >>> :{
386−-- let
387−-- definition :: Definition
388−-- '["tab" ::: '[] :=> '["col" ::: 'NoDef :=> 'NotNull 'PGint4]]
389−-- '["tab" ::: '["positive" ::: Check ] :=> '["col" ::: 'NoDef :=> 'NotNull 'PGint4]]
390−-- definition = alterTable #tab (addConstraint #positive (check (#col .> 0)))
391−-- in renderDefinition definition
392−-- :}
393−-- "ALTER TABLE tab ADD CONSTRAINT positive CHECK ((col > 0));"
394−addConstraint
395− :: KnownSymbol constraintName
396− => Alias constraintName
397− -> TableConstraintExpression schema (TableToColumns table) constraint
398− -> AlterTable schema table (AddConstraint constraintName constraint table)
399−addConstraint constraintName constraint = UnsafeAlterTable $
400− "ADD" <+> "CONSTRAINT" <+> renderAlias constraintName
401− <+> renderTableConstraintExpression constraint
402−
403−dropConstraint
404− :: KnownSymbol constraintName
405− => Alias constraintName
406− -> AlterTable schema
407− (constraints :=> columns)
408− (Drop constraintName constraints :=> columns)
409−dropConstraint constraint = UnsafeAlterTable $
410− "DROP" <+> "CONSTRAINT" <+> renderAlias constraint
411−
412−-- | An `AlterTable` describes the alteration to perform on the columns
413−-- of a table.
414−newtype AlterTable
415− (schema :: TablesType)
416− (table0 :: TableType)
417− (table1 :: TableType) =
418− UnsafeAlterTable {renderAlterTable :: ByteString}
419− deriving (GHC.Generic,Show,Eq,Ord,NFData)
420−
421−-- | An `addColumnDefault` adds a new `Optional` column. The new column is
422−-- initially filled with whatever default value is given.
423−--
424−-- >>> :{
425−-- let
426−-- definition :: Definition
427−-- '["tab" ::: '["col1" ::: 'Required ('Null 'PGint4)]]
428−-- '["tab" :::
429−-- '[ "col1" ::: 'Required ('Null 'PGint4)
430−-- , "col2" ::: 'Optional ('Null 'PGtext) ]]
431−-- definition = alterTable #tab
432−-- (addColumnDefault #col2 (text & default_ "foo"))
433−-- in renderDefinition definition
434−-- :}
435−-- "ALTER TABLE tab ADD COLUMN col2 text DEFAULT E'foo';"
436−addColumnDefault
437− :: KnownSymbol column
438− => Alias column -- ^ column to add
439− -> TypeExpression ('Def :=> ty) -- ^ type of the new column
440− -> AlterTable schema table (AddColumn column ('Def :=> ty) table)
441−addColumnDefault column ty = UnsafeAlterTable $
442− "ADD COLUMN" <+> renderAlias column <+> renderTypeExpression ty
443−
444−-- | An `addColumnNull` adds a new `Null` column. The new column is initially
445−-- filled with @NULL@s.
446−--
447−-- >>> :{
448−-- let
449−-- definition :: Definition
450−-- '["tab" ::: '["col1" ::: 'Required ('Null 'PGint4)]]
451−-- '["tab" :::
452−-- '[ "col1" ::: 'Required ('Null 'PGint4)
453−-- , "col2" ::: 'Required ('Null 'PGtext) ]]
454−-- definition = alterTable #tab (addColumnNull #col2 text)
455−-- in renderDefinition definition
456−-- :}
457−-- "ALTER TABLE tab ADD COLUMN col2 text;"
458−addColumnNull
459− :: KnownSymbol column
460− => Alias column -- ^ column to add
461− -> TypeExpression ('NoDef :=> 'Null ty) -- ^ type of the new column
462− -> AlterTable schema table (AddColumn column ('NoDef :=> 'Null ty) table)
463−addColumnNull column ty = UnsafeAlterTable $
464− "ADD COLUMN" <+> renderAlias column <+> renderTypeExpression ty
465−
466−-- | A `dropColumn` removes a column. Whatever data was in the column
467−-- disappears. Table constraints involving the column are dropped, too.
468−-- However, if the column is referenced by a foreign key constraint of
469−-- another table, PostgreSQL will not silently drop that constraint.
470−--
471−-- >>> :{
472−-- let
473−-- definition :: Definition
474−-- '["tab" :::
475−-- '[ "col1" ::: 'Required ('Null 'PGint4)
476−-- , "col2" ::: 'Required ('Null 'PGtext) ]]
477−-- '["tab" ::: '["col1" ::: 'Required ('Null 'PGint4)]]
478−-- definition = alterTable #tab (dropColumn #col2)
479−-- in renderDefinition definition
480−-- :}
481−-- "ALTER TABLE tab DROP COLUMN col2;"
482−dropColumn
483− :: KnownSymbol column
484− => Alias column -- ^ column to remove
485− -> AlterTable schema ('[] :=> columns) ('[] :=> Drop column columns)
486−dropColumn column = UnsafeAlterTable $
487− "DROP COLUMN" <+> renderAlias column
488−
489−-- | Like `dropColumn` but authorizes dropping everything that depends
490−-- on the column.
491−--
492−-- >>> :{
493−-- let
494−-- definition :: Definition
495−-- '["tab" :::
496−-- '[ "col1" ::: 'Required ('Null 'PGint4)
497−-- , "col2" ::: 'Required ('Null 'PGtext) ]]
498−-- '["tab" ::: '["col1" ::: 'Required ('Null 'PGint4)]]
499−-- definition = alterTable #tab (dropColumnCascade #col2)
500−-- in renderDefinition definition
501−-- :}
502−-- "ALTER TABLE tab DROP COLUMN col2 CASCADE;"
503−-- dropColumnCascade
504−-- :: KnownSymbol column
505−-- => Alias column -- ^ column to remove
506−-- -> AlterTable schema columns (Drop column columns)
507−-- dropColumnCascade column = UnsafeAlterTable $
508−-- "DROP COLUMN" <+> renderAlias column <+> "CASCADE"
509−
510−-- | A `renameColumn` renames a column.
511−--
512−-- >>> :{
513−-- let
514−-- definition :: Definition
515−-- '["tab" ::: '["foo" ::: 'Required ('Null 'PGint4)]]
516−-- '["tab" ::: '["bar" ::: 'Required ('Null 'PGint4)]]
517−-- definition = alterTable #tab (renameColumn #foo #bar)
518−-- in renderDefinition definition
519−-- :}
520−-- "ALTER TABLE tab RENAME COLUMN foo TO bar;"
521−renameColumn
522− :: (KnownSymbol column0, KnownSymbol column1)
523− => Alias column0
524− -> Alias column1
525− -> AlterTable schema ('[] :=> columns)
526− ('[] :=> Rename column0 column1 columns)
527−renameColumn column0 column1 = UnsafeAlterTable $
528− "RENAME COLUMN" <+> renderAlias column0 <+> "TO" <+> renderAlias column1
529−
530−-- | An `alterColumn` alters a single column.
531−alterColumn
532− :: (KnownSymbol column, Has column columns ty0)
533− => Alias column -- ^ column to alter
534− -> AlterColumn ty0 ty1 -- ^ alteration to perform
535− -> AlterTable schema ('[] :=> columns) ('[] :=> Alter column columns ty1)
536−alterColumn column alteration = UnsafeAlterTable $
537− "ALTER COLUMN" <+> renderAlias column <+> renderAlterColumn alteration
538−
539−-- | An `AlterColumn` describes the alteration to perform on a single column.
540−newtype AlterColumn (ty0 :: ColumnType) (ty1 :: ColumnType) =
541− UnsafeAlterColumn {renderAlterColumn :: ByteString}
542− deriving (GHC.Generic,Show,Eq,Ord,NFData)
543−
544−-- | A `setDefault` sets a new default for a column. Note that this doesn't
545−-- affect any existing rows in the table, it just changes the default for
546−-- future `insertTable` and `updateTable` commands.
547−--
548−-- >>> :{
549−-- let
550−-- definition :: Definition
551−-- '["tab" ::: '["col" ::: 'Required ('Null 'PGint4)]]
552−-- '["tab" ::: '["col" ::: 'Optional ('Null 'PGint4)]]
553−-- definition = alterTable #tab (alterColumn #col (setDefault 5))
554−-- in renderDefinition definition
555−-- :}
556−-- "ALTER TABLE tab ALTER COLUMN col SET DEFAULT 5;"
557−setDefault
558− :: Expression '[] 'Ungrouped '[] ty -- ^ default value to set
559− -> AlterColumn (constraints :=> ty) ('Def :=> ty)
560−setDefault expression = UnsafeAlterColumn $
561− "SET DEFAULT" <+> renderExpression expression
562−
563−-- | A `dropDefault` removes any default value for a column.
564−--
565−-- >>> :{
566−-- let
567−-- definition :: Definition
568−-- '["tab" ::: '["col" ::: 'Optional ('Null 'PGint4)]]
569−-- '["tab" ::: '["col" ::: 'Required ('Null 'PGint4)]]
570−-- definition = alterTable #tab (alterColumn #col dropDefault)
571−-- in renderDefinition definition
572−-- :}
573−-- "ALTER TABLE tab ALTER COLUMN col DROP DEFAULT;"
574−dropDefault :: AlterColumn ('Def :=> ty) ('NoDef :=> ty)
575−dropDefault = UnsafeAlterColumn $ "DROP DEFAULT"
576−
577−-- | A `setNotNull` adds a @NOT NULL@ constraint to a column.
578−-- The constraint will be checked immediately, so the table data must satisfy
579−-- the constraint before it can be added.
580−--
581−-- >>> :{
582−-- let
583−-- definition :: Definition
584−-- '["tab" ::: '["col" ::: 'Required ('Null 'PGint4)]]
585−-- '["tab" ::: '["col" ::: 'Required ('NotNull 'PGint4)]]
586−-- definition = alterTable #tab (alterColumn #col setNotNull)
587−-- in renderDefinition definition
588−-- :}
589−-- "ALTER TABLE tab ALTER COLUMN col SET NOT NULL;"
590−setNotNull :: AlterColumn (optionality ('Null ty)) (optionality ('NotNull ty))
591−setNotNull = UnsafeAlterColumn $ "SET NOT NULL"
592−
593−-- | A `dropNotNull` drops a @NOT NULL@ constraint from a column.
594−--
595−-- >>> :{
596−-- let
597−-- definition :: Definition
598−-- '["tab" ::: '["col" ::: 'Required ('NotNull 'PGint4)]]
599−-- '["tab" ::: '["col" ::: 'Required ('Null 'PGint4)]]
600−-- definition = alterTable #tab (alterColumn #col dropNotNull)
601−-- in renderDefinition definition
602−-- :}
603−-- "ALTER TABLE tab ALTER COLUMN col DROP NOT NULL;"
604−dropNotNull :: AlterColumn (optionality ('NotNull ty)) (optionality ('Null ty))
605−dropNotNull = UnsafeAlterColumn $ "DROP NOT NULL"
606−
607−-- | An `alterType` converts a column to a different data type.
608−-- This will succeed only if each existing entry in the column can be
609−-- converted to the new type by an implicit cast.
610−--
611−-- >>> :{
612−-- let
613−-- definition :: Definition
614−-- '["tab" ::: '["col" ::: 'Required ('NotNull 'PGint4)]]
615−-- '["tab" ::: '["col" ::: 'Required ('NotNull 'PGnumeric)]]
616−-- definition =
617−-- alterTable #tab (alterColumn #col (alterType (numeric & notNull)))
618−-- in renderDefinition definition
619−-- :}
620−-- "ALTER TABLE tab ALTER COLUMN col TYPE numeric NOT NULL;"
621−alterType :: TypeExpression ty -> AlterColumn ty0 ty
622−alterType ty = UnsafeAlterColumn $ "TYPE" <+> renderTypeExpression ty
74+ renderSQL ddl0 <> "\n" <> renderSQL ddl1
75+
76+-- | A `Manipulation` without input or output can be run as a statement
77+-- along with other `Definition`s, by embedding it using `manipDefinition`.
78+manipDefinition
79+ :: Manipulation '[] schemas '[] '[]
80+ -- ^ no input or output
81+ -> Definition schemas schemas
82+manipDefinition = UnsafeDefinition . (<> ";") . renderSQL
squeal-postgresql/src/Squeal/PostgreSQL/Definition/Function.hsnew file+238
@@ -0,0 +1,238 @@
1+{-|
2+Module: Squeal.PostgreSQL.Definition.Function
3+Description: Create and drop function and operator definitions
4+Copyright: (c) Eitan Chatav, 2017
5+Maintainer: eitan@morphism.tech
6+Stability: experimental
7+
8+Create and drop function and operator definitions.
9+-}
10+
11+{-# LANGUAGE
12+ AllowAmbiguousTypes
13+ , ConstraintKinds
14+ , DeriveAnyClass
15+ , DeriveGeneric
16+ , DerivingStrategies
17+ , FlexibleContexts
18+ , FlexibleInstances
19+ , GADTs
20+ , LambdaCase
21+ , MultiParamTypeClasses
22+ , OverloadedLabels
23+ , OverloadedStrings
24+ , RankNTypes
25+ , ScopedTypeVariables
26+ , TypeApplications
27+ , TypeInType
28+ , TypeOperators
29+ , UndecidableSuperClasses
30+#-}
31+
32+module Squeal.PostgreSQL.Definition.Function
33+ ( createFunction
34+ , createOrReplaceFunction
35+ , createSetFunction
36+ , createOrReplaceSetFunction
37+ , createBinaryOp
38+ , createLeftOp
39+ , createRightOp
40+ , dropFunction
41+ , dropFunctionIfExists
42+ , dropOperator
43+ , dropOperatorIfExists
44+ , FunctionDefinition(..)
45+ , languageSqlExpr
46+ , languageSqlQuery
47+ ) where
48+
49+import Control.DeepSeq
50+import Data.ByteString
51+import GHC.TypeLits
52+
53+import qualified Generics.SOP as SOP
54+import qualified GHC.Generics as GHC
55+
56+import Squeal.PostgreSQL.Alias
57+import Squeal.PostgreSQL.Definition
58+import Squeal.PostgreSQL.Expression
59+import Squeal.PostgreSQL.Expression.Type
60+import Squeal.PostgreSQL.List
61+import Squeal.PostgreSQL.Query
62+import Squeal.PostgreSQL.Render
63+import Squeal.PostgreSQL.Schema
64+
65+-- $setup
66+-- >>> import Squeal.PostgreSQL
67+
68+createFunction
69+ :: ( Has sch schemas schema
70+ , KnownSymbol fun
71+ , SOP.SListI args )
72+ => QualifiedAlias sch fun
73+ -> NP (TypeExpression schemas) args
74+ -> TypeExpression schemas ret
75+ -> FunctionDefinition schemas args ('Returns ret)
76+ -> Definition schemas (Alter sch (Create fun ('Function (args :=> 'Returns ret)) schema) schemas)
77+createFunction fun args ret fundef = UnsafeDefinition $
78+ "CREATE" <+> "FUNCTION" <+> renderSQL fun
79+ <+> parenthesized (renderCommaSeparated renderSQL args)
80+ <+> "RETURNS" <+> renderSQL ret <+> renderSQL fundef <> ";"
81+
82+createOrReplaceFunction
83+ :: ( Has sch schemas schema
84+ , KnownSymbol fun
85+ , SOP.SListI args )
86+ => QualifiedAlias sch fun
87+ -> NP (TypeExpression schemas) args
88+ -> TypeExpression schemas ret
89+ -> FunctionDefinition schemas args ('Returns ret)
90+ -> Definition schemas (Alter sch (CreateOrReplace fun ('Function (args :=> 'Returns ret)) schema) schemas)
91+createOrReplaceFunction fun args ret fundef = UnsafeDefinition $
92+ "CREATE" <+> "OR" <+> "REPLACE" <+> "FUNCTION" <+> renderSQL fun
93+ <+> parenthesized (renderCommaSeparated renderSQL args)
94+ <+> "RETURNS" <+> renderSQL ret <+> renderSQL fundef <> ";"
95+
96+languageSqlExpr
97+ :: Expression '[] '[] 'Ungrouped schemas args '[] ret
98+ -> FunctionDefinition schemas args ('Returns ret)
99+languageSqlExpr expr = UnsafeFunctionDefinition $
100+ "language sql as"
101+ <+> "$$" <+> renderSQL (values_ (expr `as` #ret)) <+> "$$"
102+
103+languageSqlQuery
104+ :: Query '[] '[] schemas args rets
105+ -> FunctionDefinition schemas args ('ReturnsTable rets)
106+languageSqlQuery qry = UnsafeFunctionDefinition $
107+ "language sql as" <+> "$$" <+> renderSQL qry <+> "$$"
108+
109+createSetFunction
110+ :: ( Has sch schemas schema
111+ , KnownSymbol fun
112+ , SOP.SListI args
113+ , SOP.SListI rets )
114+ => QualifiedAlias sch fun
115+ -> NP (TypeExpression schemas) args
116+ -> NP (Aliased (TypeExpression schemas)) rets
117+ -> FunctionDefinition schemas args ('ReturnsTable rets)
118+ -> Definition schemas (Alter sch (Create fun ('Function (args :=> 'ReturnsTable rets)) schema) schemas)
119+createSetFunction fun args rets fundef = UnsafeDefinition $
120+ "CREATE" <+> "FUNCTION" <+> renderSQL fun
121+ <+> parenthesized (renderCommaSeparated renderSQL args)
122+ <+> "RETURNS" <+> "TABLE"
123+ <+> parenthesized (renderCommaSeparated renderRet rets)
124+ <+> renderSQL fundef <> ";"
125+ where
126+ renderRet :: Aliased (TypeExpression s) r -> ByteString
127+ renderRet (ty `As` col) = renderSQL col <+> renderSQL ty
128+
129+createOrReplaceSetFunction
130+ :: ( Has sch schemas schema
131+ , KnownSymbol fun
132+ , SOP.SListI args
133+ , SOP.SListI rets )
134+ => QualifiedAlias sch fun
135+ -> NP (TypeExpression schemas) args
136+ -> NP (Aliased (TypeExpression schemas)) rets
137+ -> FunctionDefinition schemas args ('ReturnsTable rets)
138+ -> Definition schemas (Alter sch (CreateOrReplace fun ('Function (args :=> 'ReturnsTable rets)) schema) schemas)
139+createOrReplaceSetFunction fun args rets fundef = UnsafeDefinition $
140+ "CREATE" <+> "OR" <+> "REPLACE" <+> "FUNCTION" <+> renderSQL fun
141+ <+> parenthesized (renderCommaSeparated renderSQL args)
142+ <+> "RETURNS" <+> "TABLE"
143+ <+> parenthesized (renderCommaSeparated renderRet rets)
144+ <+> renderSQL fundef <> ";"
145+ where
146+ renderRet :: Aliased (TypeExpression s) r -> ByteString
147+ renderRet (ty `As` col) = renderSQL col <+> renderSQL ty
148+
149+createBinaryOp
150+ :: forall op fun sch schemas schema x y z.
151+ ( Has sch schemas schema
152+ , Has fun schema ('Function ('[x,y] :=> 'Returns z))
153+ , KnownSymbol op )
154+ => QualifiedAlias sch fun
155+ -> TypeExpression schemas x
156+ -> TypeExpression schemas y
157+ -> Definition schemas
158+ (Alter sch (Create op ('Operator ('BinaryOp x y z)) schema) schemas)
159+createBinaryOp fun x y = UnsafeDefinition $
160+ "CREATE" <+> "OPERATOR" <+> renderSymbol @op
161+ <+> parenthesized (commaSeparated opdef)
162+ where
163+ opdef =
164+ [ "FUNCTION" <+> "=" <+> renderSQL fun
165+ , "LEFTARG" <+> "=" <+> renderSQL x
166+ , "RIGHTARG" <+> "=" <+> renderSQL y ]
167+
168+createLeftOp
169+ :: forall op fun sch schemas schema x y.
170+ ( Has sch schemas schema
171+ , Has fun schema ('Function ('[x] :=> 'Returns y))
172+ , KnownSymbol op )
173+ => QualifiedAlias sch fun
174+ -> TypeExpression schemas x
175+ -> Definition schemas
176+ (Alter sch (Create op ('Operator ('LeftOp x y)) schema) schemas)
177+createLeftOp fun x = UnsafeDefinition $
178+ "CREATE" <+> "OPERATOR" <+> renderSymbol @op
179+ <+> parenthesized (commaSeparated opdef)
180+ where
181+ opdef =
182+ [ "FUNCTION" <+> "=" <+> renderSQL fun
183+ , "RIGHTARG" <+> "=" <+> renderSQL x ]
184+
185+createRightOp
186+ :: forall op fun sch schemas schema x y.
187+ ( Has sch schemas schema
188+ , Has fun schema ('Function ('[x] :=> 'Returns y))
189+ , KnownSymbol op )
190+ => QualifiedAlias sch fun
191+ -> TypeExpression schemas x
192+ -> Definition schemas
193+ (Alter sch (Create op ('Operator ('RightOp x y)) schema) schemas)
194+createRightOp fun x = UnsafeDefinition $
195+ "CREATE" <+> "OPERATOR" <+> renderSymbol @op
196+ <+> parenthesized (commaSeparated opdef)
197+ where
198+ opdef =
199+ [ "FUNCTION" <+> "=" <+> renderSQL fun
200+ , "LEFTARG" <+> "=" <+> renderSQL x ]
201+
202+dropFunction
203+ :: (Has sch schemas schema, KnownSymbol fun)
204+ => QualifiedAlias sch fun
205+ -- ^ name of the user defined function
206+ -> Definition schemas (Alter sch (DropSchemum fun 'Function schema) schemas)
207+dropFunction fun = UnsafeDefinition $
208+ "DROP" <+> "FUNCTION" <+> renderSQL fun <> ";"
209+
210+dropFunctionIfExists
211+ :: (Has sch schemas schema, KnownSymbol fun)
212+ => QualifiedAlias sch fun
213+ -- ^ name of the user defined function
214+ -> Definition schemas (Alter sch (DropSchemumIfExists fun 'Function schema) schemas)
215+dropFunctionIfExists fun = UnsafeDefinition $
216+ "DROP FUNCTION IF EXISTS" <+> renderSQL fun <> ";"
217+
218+dropOperator
219+ :: (Has sch schemas schema, KnownSymbol op)
220+ => QualifiedAlias sch op
221+ -- ^ name of the user defined operator
222+ -> Definition schemas (Alter sch (DropSchemum op 'Operator schema) schemas)
223+dropOperator op = UnsafeDefinition $
224+ "DROP" <+> "OPERATOR" <+> renderSQL op <> ";"
225+
226+dropOperatorIfExists
227+ :: (Has sch schemas schema, KnownSymbol op)
228+ => QualifiedAlias sch op
229+ -- ^ name of the user defined operator
230+ -> Definition schemas (Alter sch (DropSchemumIfExists op 'Operator schema) schemas)
231+dropOperatorIfExists op = UnsafeDefinition $
232+ "DROP OPERATOR IF EXISTS" <+> renderSQL op <> ";"
233+
234+newtype FunctionDefinition schemas args ret = UnsafeFunctionDefinition
235+ { renderFunctionDefinition :: ByteString }
236+ deriving (Eq,Show,GHC.Generic,NFData)
237+instance RenderSQL (FunctionDefinition schemas args ret) where
238+ renderSQL = renderFunctionDefinition
squeal-postgresql/src/Squeal/PostgreSQL/Definition/Index.hsnew file+159
@@ -0,0 +1,159 @@
1+{-|
2+Module: Squeal.PostgreSQL.Definition.Index
3+Description: Create and drop index definitions
4+Copyright: (c) Eitan Chatav, 2017
5+Maintainer: eitan@morphism.tech
6+Stability: experimental
7+
8+Create and drop index definitions.
9+-}
10+
11+{-# LANGUAGE
12+ AllowAmbiguousTypes
13+ , ConstraintKinds
14+ , DeriveAnyClass
15+ , DeriveGeneric
16+ , DerivingStrategies
17+ , FlexibleContexts
18+ , FlexibleInstances
19+ , GADTs
20+ , LambdaCase
21+ , MultiParamTypeClasses
22+ , OverloadedLabels
23+ , OverloadedStrings
24+ , RankNTypes
25+ , ScopedTypeVariables
26+ , TypeApplications
27+ , TypeInType
28+ , TypeOperators
29+ , UndecidableSuperClasses
30+#-}
31+
32+module Squeal.PostgreSQL.Definition.Index
33+ ( createIndex
34+ , createIndexIfNotExists
35+ , dropIndex
36+ , dropIndexIfExists
37+ , IndexMethod (..)
38+ , btree
39+ , hash
40+ , gist
41+ , spgist
42+ , gin
43+ , brin
44+ ) where
45+
46+import Data.ByteString
47+import GHC.TypeLits
48+
49+import qualified GHC.Generics as GHC
50+
51+import Squeal.PostgreSQL.Alias
52+import Squeal.PostgreSQL.Definition
53+import Squeal.PostgreSQL.Expression.Sort
54+import Squeal.PostgreSQL.Render
55+import Squeal.PostgreSQL.Schema
56+
57+-- $setup
58+-- >>> import Squeal.PostgreSQL
59+
60+{- |
61+>>> :{
62+type Table = '[] :=>
63+ '[ "a" ::: 'NoDef :=> 'Null 'PGint4
64+ , "b" ::: 'NoDef :=> 'Null 'PGfloat4 ]
65+:}
66+
67+>>> :{
68+let
69+ setup :: Definition (Public '[]) (Public '["tab" ::: 'Table Table, "ix" ::: 'Index 'Btree])
70+ setup =
71+ createTable #tab (nullable int `as` #a :* nullable real `as` #b) Nil >>>
72+ createIndex #ix #tab btree [#a & AscNullsFirst, #b & AscNullsLast]
73+in printSQL setup
74+:}
75+CREATE TABLE "tab" ("a" int NULL, "b" real NULL);
76+CREATE INDEX "ix" ON "tab" USING btree (("a") ASC NULLS FIRST, ("b") ASC NULLS LAST);
77+-}
78+createIndex
79+ :: (Has sch schemas schema, Has tab schema ('Table table), KnownSymbol ix)
80+ => Alias ix
81+ -> QualifiedAlias sch tab
82+ -> IndexMethod method
83+ -> [SortExpression '[] '[] 'Ungrouped schemas '[] '[tab ::: TableToRow table]]
84+ -> Definition schemas (Alter sch (Create ix ('Index method) schema) schemas)
85+createIndex ix tab method cols = UnsafeDefinition $
86+ "CREATE" <+> "INDEX" <+> renderSQL ix <+> "ON" <+> renderSQL tab
87+ <+> "USING" <+> renderSQL method
88+ <+> parenthesized (commaSeparated (renderIndex <$> cols))
89+ <> ";"
90+ where
91+ renderIndex = \case
92+ Asc expression -> parenthesized (renderSQL expression) <+> "ASC"
93+ Desc expression -> parenthesized (renderSQL expression) <+> "DESC"
94+ AscNullsFirst expression -> parenthesized (renderSQL expression)
95+ <+> "ASC NULLS FIRST"
96+ DescNullsFirst expression -> parenthesized (renderSQL expression)
97+ <+> "DESC NULLS FIRST"
98+ AscNullsLast expression -> parenthesized (renderSQL expression)
99+ <+> "ASC NULLS LAST"
100+ DescNullsLast expression -> parenthesized (renderSQL expression)
101+ <+> "DESC NULLS LAST"
102+
103+createIndexIfNotExists
104+ :: (Has sch schemas schema, Has tab schema ('Table table), KnownSymbol ix)
105+ => Alias ix
106+ -> QualifiedAlias sch tab
107+ -> IndexMethod method
108+ -> [SortExpression '[] '[] 'Ungrouped schemas '[] '[tab ::: TableToRow table]]
109+ -> Definition schemas (Alter sch (CreateIfNotExists ix ('Index method) schema) schemas)
110+createIndexIfNotExists ix tab method cols = UnsafeDefinition $
111+ "CREATE INDEX IF NOT EXISTS" <+> renderSQL ix <+> "ON" <+> renderSQL tab
112+ <+> "USING" <+> renderSQL method
113+ <+> parenthesized (commaSeparated (renderIndex <$> cols))
114+ <> ";"
115+ where
116+ renderIndex = \case
117+ Asc expression -> parenthesized (renderSQL expression) <+> "ASC"
118+ Desc expression -> parenthesized (renderSQL expression) <+> "DESC"
119+ AscNullsFirst expression -> parenthesized (renderSQL expression)
120+ <+> "ASC NULLS FIRST"
121+ DescNullsFirst expression -> parenthesized (renderSQL expression)
122+ <+> "DESC NULLS FIRST"
123+ AscNullsLast expression -> parenthesized (renderSQL expression)
124+ <+> "ASC NULLS LAST"
125+ DescNullsLast expression -> parenthesized (renderSQL expression)
126+ <+> "DESC NULLS LAST"
127+
128+newtype IndexMethod ty = UnsafeIndexMethod {renderIndexMethod :: ByteString}
129+ deriving stock (Eq, Ord, Show, GHC.Generic)
130+instance RenderSQL (IndexMethod ty) where renderSQL = renderIndexMethod
131+btree :: IndexMethod 'Btree
132+btree = UnsafeIndexMethod "btree"
133+hash :: IndexMethod 'Hash
134+hash = UnsafeIndexMethod "hash"
135+gist :: IndexMethod 'Gist
136+gist = UnsafeIndexMethod "gist"
137+spgist :: IndexMethod 'Spgist
138+spgist = UnsafeIndexMethod "spgist"
139+gin :: IndexMethod 'Gin
140+gin = UnsafeIndexMethod "gin"
141+brin :: IndexMethod 'Brin
142+brin = UnsafeIndexMethod "brin"
143+
144+-- |
145+-- >>> printSQL (dropIndex #ix :: Definition (Public '["ix" ::: 'Index 'Btree]) (Public '[]))
146+-- DROP INDEX "ix";
147+dropIndex
148+ :: (Has sch schemas schema, KnownSymbol ix)
149+ => QualifiedAlias sch ix
150+ -- ^ name of the user defined index
151+ -> Definition schemas (Alter sch (DropSchemum ix 'Index schema) schemas)
152+dropIndex ix = UnsafeDefinition $ "DROP" <+> "INDEX" <+> renderSQL ix <> ";"
153+
154+dropIndexIfExists
155+ :: (Has sch schemas schema, KnownSymbol ix)
156+ => QualifiedAlias sch ix
157+ -- ^ name of the user defined index
158+ -> Definition schemas (Alter sch (DropSchemumIfExists ix 'Index schema) schemas)
159+dropIndexIfExists ix = UnsafeDefinition $ "DROP INDEX IF EXISTS" <+> renderSQL ix <> ";"
squeal-postgresql/src/Squeal/PostgreSQL/Definition/Schema.hsnew file+96
@@ -0,0 +1,96 @@
1+{-|
2+Module: Squeal.PostgreSQL.Definition.Schema
3+Description: Create and drop schema definitions
4+Copyright: (c) Eitan Chatav, 2017
5+Maintainer: eitan@morphism.tech
6+Stability: experimental
7+
8+Create and drop schema definitions.
9+-}
10+
11+{-# LANGUAGE
12+ AllowAmbiguousTypes
13+ , ConstraintKinds
14+ , DeriveAnyClass
15+ , DeriveGeneric
16+ , DerivingStrategies
17+ , FlexibleContexts
18+ , FlexibleInstances
19+ , GADTs
20+ , LambdaCase
21+ , MultiParamTypeClasses
22+ , OverloadedLabels
23+ , OverloadedStrings
24+ , RankNTypes
25+ , ScopedTypeVariables
26+ , TypeApplications
27+ , TypeInType
28+ , TypeOperators
29+ , UndecidableSuperClasses
30+#-}
31+
32+module Squeal.PostgreSQL.Definition.Schema
33+ ( createSchema
34+ , createSchemaIfNotExists
35+ , dropSchema
36+ , dropSchemaIfExists
37+ ) where
38+
39+import GHC.TypeLits
40+
41+import Squeal.PostgreSQL.Alias
42+import Squeal.PostgreSQL.Definition
43+import Squeal.PostgreSQL.Render
44+import Squeal.PostgreSQL.Schema
45+
46+-- $setup
47+-- >>> import Squeal.PostgreSQL
48+
49+{- |
50+`createSchema` enters a new schema into the current database.
51+The schema name must be distinct from the name of any existing schema
52+in the current database.
53+
54+A schema is essentially a namespace: it contains named objects
55+(tables, data types, functions, and operators) whose names
56+can duplicate those of other objects existing in other schemas.
57+Named objects are accessed by `QualifiedAlias`es with the schema
58+name as a prefix.
59+-}
60+createSchema
61+ :: KnownSymbol sch
62+ => Alias sch
63+ -> Definition schemas (Create sch '[] schemas)
64+createSchema sch = UnsafeDefinition $
65+ "CREATE" <+> "SCHEMA" <+> renderSQL sch <> ";"
66+
67+{- | Idempotent version of `createSchema`. -}
68+createSchemaIfNotExists
69+ :: (KnownSymbol sch, Has sch schemas schema)
70+ => Alias sch
71+ -> Definition schemas (CreateIfNotExists sch '[] schemas)
72+createSchemaIfNotExists sch = UnsafeDefinition $
73+ "CREATE" <+> "SCHEMA" <+> "IF" <+> "NOT" <+> "EXISTS"
74+ <+> renderSQL sch <> ";"
75+
76+-- | >>> :{
77+-- let
78+-- definition :: Definition '["muh_schema" ::: schema, "public" ::: public] '["public" ::: public]
79+-- definition = dropSchema #muh_schema
80+-- :}
81+--
82+-- >>> printSQL definition
83+-- DROP SCHEMA "muh_schema";
84+dropSchema
85+ :: KnownSymbol sch
86+ => Alias sch
87+ -- ^ user defined schema
88+ -> Definition schemas (Drop sch schemas)
89+dropSchema sch = UnsafeDefinition $ "DROP SCHEMA" <+> renderSQL sch <> ";"
90+
91+dropSchemaIfExists
92+ :: KnownSymbol sch
93+ => Alias sch
94+ -- ^ user defined schema
95+ -> Definition schemas (DropIfExists sch schemas)
96+dropSchemaIfExists sch = UnsafeDefinition $ "DROP SCHEMA" <+> renderSQL sch <> ";"
squeal-postgresql/src/Squeal/PostgreSQL/Definition/Table.hsnew file+500
@@ -0,0 +1,500 @@
1+{-|
2+Module: Squeal.PostgreSQL.Definition.Table
3+Description: Create, drop and alter table definitions
4+Copyright: (c) Eitan Chatav, 2017
5+Maintainer: eitan@morphism.tech
6+Stability: experimental
7+
8+Create, drop and alter table definitions.
9+-}
10+
11+{-# LANGUAGE
12+ AllowAmbiguousTypes
13+ , ConstraintKinds
14+ , DeriveAnyClass
15+ , DeriveGeneric
16+ , DerivingStrategies
17+ , FlexibleContexts
18+ , FlexibleInstances
19+ , GADTs
20+ , LambdaCase
21+ , MultiParamTypeClasses
22+ , OverloadedLabels
23+ , OverloadedStrings
24+ , RankNTypes
25+ , ScopedTypeVariables
26+ , TypeApplications
27+ , TypeInType
28+ , TypeOperators
29+ , UndecidableSuperClasses
30+#-}
31+
32+module Squeal.PostgreSQL.Definition.Table
33+ ( createTable
34+ , createTableIfNotExists
35+ , dropTable
36+ , dropTableIfExists
37+ , alterTable
38+ , alterTableIfExists
39+ , alterTableRename
40+ , alterTableIfExistsRename
41+ , AlterTable (..)
42+ , addConstraint
43+ , dropConstraint
44+ , AddColumn (..)
45+ , dropColumn
46+ , renameColumn
47+ , alterColumn
48+ , AlterColumn (..)
49+ , setDefault
50+ , dropDefault
51+ , setNotNull
52+ , dropNotNull
53+ , alterType
54+ ) where
55+
56+import Control.DeepSeq
57+import Data.ByteString
58+import GHC.TypeLits
59+
60+import qualified Generics.SOP as SOP
61+import qualified GHC.Generics as GHC
62+
63+import Squeal.PostgreSQL.Alias
64+import Squeal.PostgreSQL.Definition
65+import Squeal.PostgreSQL.Definition.Table.Constraint
66+import Squeal.PostgreSQL.Expression
67+import Squeal.PostgreSQL.Expression.Type
68+import Squeal.PostgreSQL.List
69+import Squeal.PostgreSQL.Render
70+import Squeal.PostgreSQL.Schema
71+
72+-- $setup
73+-- >>> import Squeal.PostgreSQL
74+
75+{- | `createTable` adds a table to the schema.
76+
77+>>> :set -XOverloadedLabels
78+>>> :{
79+type Table = '[] :=>
80+ '[ "a" ::: 'NoDef :=> 'Null 'PGint4
81+ , "b" ::: 'NoDef :=> 'Null 'PGfloat4 ]
82+:}
83+
84+>>> :{
85+let
86+ setup :: Definition (Public '[]) (Public '["tab" ::: 'Table Table])
87+ setup = createTable #tab
88+ (nullable int `as` #a :* nullable real `as` #b) Nil
89+in printSQL setup
90+:}
91+CREATE TABLE "tab" ("a" int NULL, "b" real NULL);
92+-}
93+createTable
94+ :: ( KnownSymbol sch
95+ , KnownSymbol tab
96+ , columns ~ (col ': cols)
97+ , SOP.SListI columns
98+ , SOP.SListI constraints
99+ , Has sch schemas0 schema0
100+ , schemas1 ~ Alter sch (Create tab ('Table (constraints :=> columns)) schema0) schemas0 )
101+ => QualifiedAlias sch tab -- ^ the name of the table to add
102+ -> NP (Aliased (ColumnTypeExpression schemas0)) columns
103+ -- ^ the names and datatype of each column
104+ -> NP (Aliased (TableConstraintExpression sch tab schemas1)) constraints
105+ -- ^ constraints that must hold for the table
106+ -> Definition schemas0 schemas1
107+createTable tab columns constraints = UnsafeDefinition $
108+ "CREATE TABLE" <+> renderCreation tab columns constraints
109+
110+{-| `createTableIfNotExists` creates a table if it doesn't exist, but does not add it to the schema.
111+Instead, the schema already has the table so if the table did not yet exist, the schema was wrong.
112+`createTableIfNotExists` fixes this. Interestingly, this property makes it an idempotent in
113+the `Category` of `Definition`s.
114+
115+>>> :set -XOverloadedLabels -XTypeApplications
116+>>> :{
117+type Table = '[] :=>
118+ '[ "a" ::: 'NoDef :=> 'Null 'PGint4
119+ , "b" ::: 'NoDef :=> 'Null 'PGfloat4 ]
120+:}
121+
122+>>> type Schemas = Public '["tab" ::: 'Table Table]
123+
124+>>> :{
125+let
126+ setup :: Definition Schemas Schemas
127+ setup = createTableIfNotExists #tab
128+ (nullable int `as` #a :* nullable real `as` #b) Nil
129+in printSQL setup
130+:}
131+CREATE TABLE IF NOT EXISTS "tab" ("a" int NULL, "b" real NULL);
132+-}
133+createTableIfNotExists
134+ :: ( KnownSymbol sch
135+ , KnownSymbol tab
136+ , columns ~ (col ': cols)
137+ , SOP.SListI columns
138+ , SOP.SListI constraints
139+ , Has sch schemas0 schema0
140+ , schemas1 ~ Alter sch (CreateIfNotExists tab ('Table (constraints :=> columns)) schema0) schemas0 )
141+ => QualifiedAlias sch tab -- ^ the name of the table to add
142+ -> NP (Aliased (ColumnTypeExpression schemas0)) columns
143+ -- ^ the names and datatype of each column
144+ -> NP (Aliased (TableConstraintExpression sch tab schemas1)) constraints
145+ -- ^ constraints that must hold for the table
146+ -> Definition schemas0 schemas1
147+createTableIfNotExists tab columns constraints = UnsafeDefinition $
148+ "CREATE TABLE IF NOT EXISTS"
149+ <+> renderCreation tab columns constraints
150+
151+-- helper function for `createTable` and `createTableIfNotExists`
152+renderCreation
153+ :: ( KnownSymbol sch
154+ , KnownSymbol tab
155+ , SOP.SListI columns
156+ , SOP.SListI constraints )
157+ => QualifiedAlias sch tab -- ^ the name of the table to add
158+ -> NP (Aliased (ColumnTypeExpression schemas0)) columns
159+ -- ^ the names and datatype of each column
160+ -> NP (Aliased (TableConstraintExpression sch tab schemas1)) constraints
161+ -- ^ constraints that must hold for the table
162+ -> ByteString
163+renderCreation tab columns constraints = renderSQL tab
164+ <+> parenthesized
165+ ( renderCommaSeparated renderColumnDef columns
166+ <> ( case constraints of
167+ Nil -> ""
168+ _ -> ", " <>
169+ renderCommaSeparated renderConstraint constraints ) )
170+ <> ";"
171+ where
172+ renderColumnDef :: Aliased (ColumnTypeExpression schemas) x -> ByteString
173+ renderColumnDef (ty `As` column) =
174+ renderSQL column <+> renderColumnTypeExpression ty
175+ renderConstraint
176+ :: Aliased (TableConstraintExpression sch tab schemas) constraint
177+ -> ByteString
178+ renderConstraint (constraint `As` alias) =
179+ "CONSTRAINT" <+> renderSQL alias <+> renderSQL constraint
180+
181+-- | `dropTable` removes a table from the schema.
182+--
183+-- >>> :{
184+-- let
185+-- definition :: Definition '["public" ::: '["muh_table" ::: 'Table t]] (Public '[])
186+-- definition = dropTable #muh_table
187+-- :}
188+--
189+-- >>> printSQL definition
190+-- DROP TABLE "muh_table";
191+dropTable
192+ :: ( Has sch schemas schema
193+ , KnownSymbol tab )
194+ => QualifiedAlias sch tab -- ^ table to remove
195+ -> Definition schemas (Alter sch (DropSchemum tab 'Table schema) schemas)
196+dropTable tab = UnsafeDefinition $ "DROP TABLE" <+> renderSQL tab <> ";"
197+
198+dropTableIfExists
199+ :: ( Has sch schemas schema
200+ , KnownSymbol tab)
201+ => QualifiedAlias sch tab -- ^ table to remove
202+ -> Definition schemas (Alter sch (DropSchemumIfExists tab 'Table schema) schemas)
203+dropTableIfExists tab = UnsafeDefinition $ "DROP TABLE IF EXISTS" <+> renderSQL tab <> ";"
204+
205+-- | `alterTable` changes the definition of a table from the schema.
206+alterTable
207+ :: (Has sch schemas schema, KnownSymbol tab)
208+ => QualifiedAlias sch tab -- ^ table to alter
209+ -> AlterTable sch tab schemas table -- ^ alteration to perform
210+ -> Definition schemas (Alter sch (Alter tab ('Table table) schema) schemas)
211+alterTable tab alteration = UnsafeDefinition $
212+ "ALTER TABLE"
213+ <+> renderSQL tab
214+ <+> renderAlterTable alteration
215+ <> ";"
216+
217+-- | `alterTable` changes the definition of a table from the schema.
218+alterTableIfExists
219+ :: (Has sch schemas schema, KnownSymbol tab)
220+ => QualifiedAlias sch tab -- ^ table to alter
221+ -> AlterTable sch tab schemas table -- ^ alteration to perform
222+ -> Definition schemas (Alter sch (AlterIfExists tab ('Table table) schema) schemas)
223+alterTableIfExists tab alteration = UnsafeDefinition $
224+ "ALTER TABLE IF EXISTS"
225+ <+> renderSQL tab
226+ <+> renderAlterTable alteration
227+ <> ";"
228+
229+-- | `alterTableRename` changes the name of a table from the schema.
230+--
231+-- >>> printSQL $ alterTableRename #foo #bar
232+-- ALTER TABLE "foo" RENAME TO "bar";
233+alterTableRename
234+ :: (KnownSymbol tab0, KnownSymbol tab1)
235+ => Alias tab0 -- ^ table to rename
236+ -> Alias tab1 -- ^ what to rename it
237+ -> Definition schema (Rename tab0 tab1 schema)
238+alterTableRename tab0 tab1 = UnsafeDefinition $
239+ "ALTER TABLE" <+> renderSQL tab0
240+ <+> "RENAME TO" <+> renderSQL tab1 <> ";"
241+
242+alterTableIfExistsRename
243+ :: (KnownSymbol tab0, KnownSymbol tab1)
244+ => Alias tab0 -- ^ table to rename
245+ -> Alias tab1 -- ^ what to rename it
246+ -> Definition schema (RenameIfExists tab0 tab1 schema)
247+alterTableIfExistsRename tab0 tab1 = UnsafeDefinition $
248+ "ALTER TABLE IF EXISTS" <+> renderSQL tab0
249+ <+> "RENAME TO" <+> renderSQL tab1 <> ";"
250+
251+-- | An `AlterTable` describes the alteration to perform on the columns
252+-- of a table.
253+newtype AlterTable
254+ (sch :: Symbol)
255+ (tab :: Symbol)
256+ (schemas :: SchemasType)
257+ (table :: TableType) =
258+ UnsafeAlterTable {renderAlterTable :: ByteString}
259+ deriving (GHC.Generic,Show,Eq,Ord,NFData)
260+
261+-- | An `addConstraint` adds a table constraint.
262+--
263+-- >>> :{
264+-- let
265+-- definition :: Definition
266+-- '["public" ::: '["tab" ::: 'Table ('[] :=> '["col" ::: 'NoDef :=> 'NotNull 'PGint4])]]
267+-- '["public" ::: '["tab" ::: 'Table ('["positive" ::: 'Check '["col"]] :=> '["col" ::: 'NoDef :=> 'NotNull 'PGint4])]]
268+-- definition = alterTable #tab (addConstraint #positive (check #col (#col .> 0)))
269+-- in printSQL definition
270+-- :}
271+-- ALTER TABLE "tab" ADD CONSTRAINT "positive" CHECK (("col" > 0));
272+addConstraint
273+ :: ( KnownSymbol alias
274+ , Has sch schemas schema
275+ , Has tab schema ('Table table0)
276+ , table0 ~ (constraints :=> columns)
277+ , table1 ~ (Create alias constraint constraints :=> columns) )
278+ => Alias alias
279+ -> TableConstraintExpression sch tab schemas constraint
280+ -- ^ constraint to add
281+ -> AlterTable sch tab schemas table1
282+addConstraint alias constraint = UnsafeAlterTable $
283+ "ADD" <+> "CONSTRAINT" <+> renderSQL alias
284+ <+> renderSQL constraint
285+
286+-- | A `dropConstraint` drops a table constraint.
287+--
288+-- >>> :{
289+-- let
290+-- definition :: Definition
291+-- '["public" ::: '["tab" ::: 'Table ('["positive" ::: Check '["col"]] :=> '["col" ::: 'NoDef :=> 'NotNull 'PGint4])]]
292+-- '["public" ::: '["tab" ::: 'Table ('[] :=> '["col" ::: 'NoDef :=> 'NotNull 'PGint4])]]
293+-- definition = alterTable #tab (dropConstraint #positive)
294+-- in printSQL definition
295+-- :}
296+-- ALTER TABLE "tab" DROP CONSTRAINT "positive";
297+dropConstraint
298+ :: ( KnownSymbol constraint
299+ , Has sch schemas schema
300+ , Has tab schema ('Table table0)
301+ , table0 ~ (constraints :=> columns)
302+ , table1 ~ (Drop constraint constraints :=> columns) )
303+ => Alias constraint
304+ -- ^ constraint to drop
305+ -> AlterTable sch tab schemas table1
306+dropConstraint constraint = UnsafeAlterTable $
307+ "DROP" <+> "CONSTRAINT" <+> renderSQL constraint
308+
309+-- | An `AddColumn` is either @NULL@ or has @DEFAULT@.
310+class AddColumn ty where
311+ -- | `addColumn` adds a new column, initially filled with whatever
312+ -- default value is given or with @NULL@.
313+ --
314+ -- >>> :{
315+ -- let
316+ -- definition :: Definition
317+ -- '["public" ::: '["tab" ::: 'Table ('[] :=> '["col1" ::: 'NoDef :=> 'Null 'PGint4])]]
318+ -- '["public" ::: '["tab" ::: 'Table ('[] :=>
319+ -- '[ "col1" ::: 'NoDef :=> 'Null 'PGint4
320+ -- , "col2" ::: 'Def :=> 'Null 'PGtext ])]]
321+ -- definition = alterTable #tab (addColumn #col2 (text & nullable & default_ "foo"))
322+ -- in printSQL definition
323+ -- :}
324+ -- ALTER TABLE "tab" ADD COLUMN "col2" text NULL DEFAULT E'foo';
325+ --
326+ -- >>> :{
327+ -- let
328+ -- definition :: Definition
329+ -- '["public" ::: '["tab" ::: 'Table ('[] :=> '["col1" ::: 'NoDef :=> 'Null 'PGint4])]]
330+ -- '["public" ::: '["tab" ::: 'Table ('[] :=>
331+ -- '[ "col1" ::: 'NoDef :=> 'Null 'PGint4
332+ -- , "col2" ::: 'NoDef :=> 'Null 'PGtext ])]]
333+ -- definition = alterTable #tab (addColumn #col2 (text & nullable))
334+ -- in printSQL definition
335+ -- :}
336+ -- ALTER TABLE "tab" ADD COLUMN "col2" text NULL;
337+ addColumn
338+ :: ( KnownSymbol column
339+ , Has sch schemas schema
340+ , Has tab schema ('Table table0)
341+ , table0 ~ (constraints :=> columns) )
342+ => Alias column -- ^ column to add
343+ -> ColumnTypeExpression schemas ty -- ^ type of the new column
344+ -> AlterTable sch tab schemas (constraints :=> Create column ty columns)
345+ addColumn column ty = UnsafeAlterTable $
346+ "ADD COLUMN" <+> renderSQL column <+> renderColumnTypeExpression ty
347+instance {-# OVERLAPPING #-} AddColumn ('Def :=> ty)
348+instance {-# OVERLAPPABLE #-} AddColumn ('NoDef :=> 'Null ty)
349+
350+-- | A `dropColumn` removes a column. Whatever data was in the column
351+-- disappears. Table constraints involving the column are dropped, too.
352+-- However, if the column is referenced by a foreign key constraint of
353+-- another table, PostgreSQL will not silently drop that constraint.
354+--
355+-- >>> :{
356+-- let
357+-- definition :: Definition
358+-- '["public" ::: '["tab" ::: 'Table ('[] :=>
359+-- '[ "col1" ::: 'NoDef :=> 'Null 'PGint4
360+-- , "col2" ::: 'NoDef :=> 'Null 'PGtext ])]]
361+-- '["public" ::: '["tab" ::: 'Table ('[] :=> '["col1" ::: 'NoDef :=> 'Null 'PGint4])]]
362+-- definition = alterTable #tab (dropColumn #col2)
363+-- in printSQL definition
364+-- :}
365+-- ALTER TABLE "tab" DROP COLUMN "col2";
366+dropColumn
367+ :: ( KnownSymbol column
368+ , Has sch schemas schema
369+ , Has tab schema ('Table table0)
370+ , table0 ~ (constraints :=> columns)
371+ , table1 ~ (constraints :=> Drop column columns) )
372+ => Alias column -- ^ column to remove
373+ -> AlterTable sch tab schemas table1
374+dropColumn column = UnsafeAlterTable $
375+ "DROP COLUMN" <+> renderSQL column
376+
377+-- | A `renameColumn` renames a column.
378+--
379+-- >>> :{
380+-- let
381+-- definition :: Definition
382+-- '["public" ::: '["tab" ::: 'Table ('[] :=> '["foo" ::: 'NoDef :=> 'Null 'PGint4])]]
383+-- '["public" ::: '["tab" ::: 'Table ('[] :=> '["bar" ::: 'NoDef :=> 'Null 'PGint4])]]
384+-- definition = alterTable #tab (renameColumn #foo #bar)
385+-- in printSQL definition
386+-- :}
387+-- ALTER TABLE "tab" RENAME COLUMN "foo" TO "bar";
388+renameColumn
389+ :: ( KnownSymbol column0
390+ , KnownSymbol column1
391+ , Has sch schemas schema
392+ , Has tab schema ('Table table0)
393+ , table0 ~ (constraints :=> columns)
394+ , table1 ~ (constraints :=> Rename column0 column1 columns) )
395+ => Alias column0 -- ^ column to rename
396+ -> Alias column1 -- ^ what to rename the column
397+ -> AlterTable sch tab schemas table1
398+renameColumn column0 column1 = UnsafeAlterTable $
399+ "RENAME COLUMN" <+> renderSQL column0 <+> "TO" <+> renderSQL column1
400+
401+-- | An `alterColumn` alters a single column.
402+alterColumn
403+ :: ( KnownSymbol column
404+ , Has sch schemas schema
405+ , Has tab schema ('Table table0)
406+ , table0 ~ (constraints :=> columns)
407+ , Has column columns ty0
408+ , table1 ~ (constraints :=> Alter column ty1 columns))
409+ => Alias column -- ^ column to alter
410+ -> AlterColumn schemas ty0 ty1 -- ^ alteration to perform
411+ -> AlterTable sch tab schemas table1
412+alterColumn column alteration = UnsafeAlterTable $
413+ "ALTER COLUMN" <+> renderSQL column <+> renderAlterColumn alteration
414+
415+-- | An `AlterColumn` describes the alteration to perform on a single column.
416+newtype AlterColumn (schemas :: SchemasType) (ty0 :: ColumnType) (ty1 :: ColumnType) =
417+ UnsafeAlterColumn {renderAlterColumn :: ByteString}
418+ deriving (GHC.Generic,Show,Eq,Ord,NFData)
419+
420+-- | A `setDefault` sets a new default for a column. Note that this doesn't
421+-- affect any existing rows in the table, it just changes the default for
422+-- future insert and update commands.
423+--
424+-- >>> :{
425+-- let
426+-- definition :: Definition
427+-- '["public" ::: '["tab" ::: 'Table ('[] :=> '["col" ::: 'NoDef :=> 'Null 'PGint4])]]
428+-- '["public" ::: '["tab" ::: 'Table ('[] :=> '["col" ::: 'Def :=> 'Null 'PGint4])]]
429+-- definition = alterTable #tab (alterColumn #col (setDefault 5))
430+-- in printSQL definition
431+-- :}
432+-- ALTER TABLE "tab" ALTER COLUMN "col" SET DEFAULT 5;
433+setDefault
434+ :: Expression '[] '[] 'Ungrouped schemas '[] '[] ty -- ^ default value to set
435+ -> AlterColumn schemas (constraint :=> ty) ('Def :=> ty)
436+setDefault expression = UnsafeAlterColumn $
437+ "SET DEFAULT" <+> renderExpression expression
438+
439+-- | A `dropDefault` removes any default value for a column.
440+--
441+-- >>> :{
442+-- let
443+-- definition :: Definition
444+-- '["public" ::: '["tab" ::: 'Table ('[] :=> '["col" ::: 'Def :=> 'Null 'PGint4])]]
445+-- '["public" ::: '["tab" ::: 'Table ('[] :=> '["col" ::: 'NoDef :=> 'Null 'PGint4])]]
446+-- definition = alterTable #tab (alterColumn #col dropDefault)
447+-- in printSQL definition
448+-- :}
449+-- ALTER TABLE "tab" ALTER COLUMN "col" DROP DEFAULT;
450+dropDefault :: AlterColumn schemas ('Def :=> ty) ('NoDef :=> ty)
451+dropDefault = UnsafeAlterColumn $ "DROP DEFAULT"
452+
453+-- | A `setNotNull` adds a @NOT NULL@ constraint to a column.
454+-- The constraint will be checked immediately, so the table data must satisfy
455+-- the constraint before it can be added.
456+--
457+-- >>> :{
458+-- let
459+-- definition :: Definition
460+-- '["public" ::: '["tab" ::: 'Table ('[] :=> '["col" ::: 'NoDef :=> 'Null 'PGint4])]]
461+-- '["public" ::: '["tab" ::: 'Table ('[] :=> '["col" ::: 'NoDef :=> 'NotNull 'PGint4])]]
462+-- definition = alterTable #tab (alterColumn #col setNotNull)
463+-- in printSQL definition
464+-- :}
465+-- ALTER TABLE "tab" ALTER COLUMN "col" SET NOT NULL;
466+setNotNull
467+ :: AlterColumn schemas (constraint :=> 'Null ty) (constraint :=> 'NotNull ty)
468+setNotNull = UnsafeAlterColumn $ "SET NOT NULL"
469+
470+-- | A `dropNotNull` drops a @NOT NULL@ constraint from a column.
471+--
472+-- >>> :{
473+-- let
474+-- definition :: Definition
475+-- '["public" ::: '["tab" ::: 'Table ('[] :=> '["col" ::: 'NoDef :=> 'NotNull 'PGint4])]]
476+-- '["public" ::: '["tab" ::: 'Table ('[] :=> '["col" ::: 'NoDef :=> 'Null 'PGint4])]]
477+-- definition = alterTable #tab (alterColumn #col dropNotNull)
478+-- in printSQL definition
479+-- :}
480+-- ALTER TABLE "tab" ALTER COLUMN "col" DROP NOT NULL;
481+dropNotNull
482+ :: AlterColumn schemas (constraint :=> 'NotNull ty) (constraint :=> 'Null ty)
483+dropNotNull = UnsafeAlterColumn $ "DROP NOT NULL"
484+
485+-- | An `alterType` converts a column to a different data type.
486+-- This will succeed only if each existing entry in the column can be
487+-- converted to the new type by an implicit cast.
488+--
489+-- >>> :{
490+-- let
491+-- definition :: Definition
492+-- '["public" ::: '["tab" ::: 'Table ('[] :=> '["col" ::: 'NoDef :=> 'NotNull 'PGint4])]]
493+-- '["public" ::: '["tab" ::: 'Table ('[] :=> '["col" ::: 'NoDef :=> 'NotNull 'PGnumeric])]]
494+-- definition =
495+-- alterTable #tab (alterColumn #col (alterType (numeric & notNullable)))
496+-- in printSQL definition
497+-- :}
498+-- ALTER TABLE "tab" ALTER COLUMN "col" TYPE numeric NOT NULL;
499+alterType :: ColumnTypeExpression schemas ty -> AlterColumn schemas ty0 ty
500+alterType ty = UnsafeAlterColumn $ "TYPE" <+> renderColumnTypeExpression ty
squeal-postgresql/src/Squeal/PostgreSQL/Definition/Table/Constraint.hsnew file+339
@@ -0,0 +1,339 @@
1+{-|
2+Module: Squeal.PostgreSQL.Definition.Table.Constraint
3+Description: Table constraint expressions
4+Copyright: (c) Eitan Chatav, 2017
5+Maintainer: eitan@morphism.tech
6+Stability: experimental
7+
8+Table constraint expressions.
9+-}
10+
11+{-# LANGUAGE
12+ AllowAmbiguousTypes
13+ , ConstraintKinds
14+ , DeriveAnyClass
15+ , DeriveGeneric
16+ , DerivingStrategies
17+ , FlexibleContexts
18+ , FlexibleInstances
19+ , GADTs
20+ , LambdaCase
21+ , MultiParamTypeClasses
22+ , OverloadedLabels
23+ , OverloadedStrings
24+ , RankNTypes
25+ , ScopedTypeVariables
26+ , TypeApplications
27+ , TypeInType
28+ , TypeOperators
29+ , UndecidableSuperClasses
30+#-}
31+
32+module Squeal.PostgreSQL.Definition.Table.Constraint
33+ ( TableConstraintExpression (..)
34+ , check
35+ , unique
36+ , primaryKey
37+ , foreignKey
38+ , ForeignKeyed
39+ , OnDeleteClause (..)
40+ , OnUpdateClause (..)
41+ ) where
42+
43+import Control.DeepSeq
44+import Data.ByteString
45+import GHC.TypeLits
46+
47+import qualified Generics.SOP as SOP
48+import qualified GHC.Generics as GHC
49+
50+import Squeal.PostgreSQL.Alias
51+import Squeal.PostgreSQL.Expression.Logic
52+import Squeal.PostgreSQL.List
53+import Squeal.PostgreSQL.Render
54+import Squeal.PostgreSQL.Schema
55+
56+-- $setup
57+-- >>> import Squeal.PostgreSQL
58+
59+-- | Data types are a way to limit the kind of data that can be stored in a
60+-- table. For many applications, however, the constraint they provide is
61+-- too coarse. For example, a column containing a product price should
62+-- probably only accept positive values. But there is no standard data type
63+-- that accepts only positive numbers. Another issue is that you might want
64+-- to constrain column data with respect to other columns or rows.
65+-- For example, in a table containing product information,
66+-- there should be only one row for each product number.
67+-- `TableConstraint`s give you as much control over the data in your tables
68+-- as you wish. If a user attempts to store data in a column that would
69+-- violate a constraint, an error is raised. This applies
70+-- even if the value came from the default value definition.
71+newtype TableConstraintExpression
72+ (sch :: Symbol)
73+ (tab :: Symbol)
74+ (schemas :: SchemasType)
75+ (constraint :: TableConstraint)
76+ = UnsafeTableConstraintExpression
77+ { renderTableConstraintExpression :: ByteString }
78+ deriving (GHC.Generic,Show,Eq,Ord,NFData)
79+instance RenderSQL
80+ (TableConstraintExpression sch tab schemas constraint) where
81+ renderSQL = renderTableConstraintExpression
82+
83+{-| A `check` constraint is the most generic `TableConstraint` type.
84+It allows you to specify that the value in a certain column must satisfy
85+a Boolean (truth-value) expression.
86+
87+>>> :{
88+type Schema = '[
89+ "tab" ::: 'Table ('[ "inequality" ::: 'Check '["a","b"]] :=> '[
90+ "a" ::: 'NoDef :=> 'NotNull 'PGint4,
91+ "b" ::: 'NoDef :=> 'NotNull 'PGint4
92+ ])]
93+:}
94+
95+>>> :{
96+let
97+ definition :: Definition (Public '[]) (Public Schema)
98+ definition = createTable #tab
99+ ( (int & notNullable) `as` #a :*
100+ (int & notNullable) `as` #b )
101+ ( check (#a :* #b) (#a .> #b) `as` #inequality )
102+:}
103+
104+>>> printSQL definition
105+CREATE TABLE "tab" ("a" int NOT NULL, "b" int NOT NULL, CONSTRAINT "inequality" CHECK (("a" > "b")));
106+-}
107+check
108+ :: ( Has sch schemas schema
109+ , Has tab schema ('Table table)
110+ , HasAll aliases (TableToRow table) subcolumns )
111+ => NP Alias aliases
112+ -- ^ specify the subcolumns which are getting checked
113+ -> (forall t. Condition '[] '[] 'Ungrouped schemas '[] '[t ::: subcolumns])
114+ -- ^ a closed `Condition` on those subcolumns
115+ -> TableConstraintExpression sch tab schemas ('Check aliases)
116+check _cols condition = UnsafeTableConstraintExpression $
117+ "CHECK" <+> parenthesized (renderSQL condition)
118+
119+{-| A `unique` constraint ensure that the data contained in a column,
120+or a group of columns, is unique among all the rows in the table.
121+
122+>>> :{
123+type Schema = '[
124+ "tab" ::: 'Table( '[ "uq_a_b" ::: 'Unique '["a","b"]] :=> '[
125+ "a" ::: 'NoDef :=> 'Null 'PGint4,
126+ "b" ::: 'NoDef :=> 'Null 'PGint4
127+ ])]
128+:}
129+
130+>>> :{
131+let
132+ definition :: Definition (Public '[]) (Public Schema)
133+ definition = createTable #tab
134+ ( (int & nullable) `as` #a :*
135+ (int & nullable) `as` #b )
136+ ( unique (#a :* #b) `as` #uq_a_b )
137+:}
138+
139+>>> printSQL definition
140+CREATE TABLE "tab" ("a" int NULL, "b" int NULL, CONSTRAINT "uq_a_b" UNIQUE ("a", "b"));
141+-}
142+unique
143+ :: ( Has sch schemas schema
144+ , Has tab schema('Table table)
145+ , HasAll aliases (TableToRow table) subcolumns )
146+ => NP Alias aliases
147+ -- ^ specify subcolumns which together are unique for each row
148+ -> TableConstraintExpression sch tab schemas ('Unique aliases)
149+unique columns = UnsafeTableConstraintExpression $
150+ "UNIQUE" <+> parenthesized (renderSQL columns)
151+
152+{-| A `primaryKey` constraint indicates that a column, or group of columns,
153+can be used as a unique identifier for rows in the table.
154+This requires that the values be both unique and not null.
155+
156+>>> :{
157+type Schema = '[
158+ "tab" ::: 'Table ('[ "pk_id" ::: 'PrimaryKey '["id"]] :=> '[
159+ "id" ::: 'Def :=> 'NotNull 'PGint4,
160+ "name" ::: 'NoDef :=> 'NotNull 'PGtext
161+ ])]
162+:}
163+
164+>>> :{
165+let
166+ definition :: Definition (Public '[]) (Public Schema)
167+ definition = createTable #tab
168+ ( serial `as` #id :*
169+ (text & notNullable) `as` #name )
170+ ( primaryKey #id `as` #pk_id )
171+:}
172+
173+>>> printSQL definition
174+CREATE TABLE "tab" ("id" serial, "name" text NOT NULL, CONSTRAINT "pk_id" PRIMARY KEY ("id"));
175+-}
176+primaryKey
177+ :: ( Has sch schemas schema
178+ , Has tab schema ('Table table)
179+ , HasAll aliases (TableToColumns table) subcolumns
180+ , AllNotNull subcolumns )
181+ => NP Alias aliases
182+ -- ^ specify the subcolumns which together form a primary key.
183+ -> TableConstraintExpression sch tab schemas ('PrimaryKey aliases)
184+primaryKey columns = UnsafeTableConstraintExpression $
185+ "PRIMARY KEY" <+> parenthesized (renderSQL columns)
186+
187+{-| A `foreignKey` specifies that the values in a column
188+(or a group of columns) must match the values appearing in some row of
189+another table. We say this maintains the referential integrity
190+between two related tables.
191+
192+>>> :{
193+type Schema =
194+ '[ "users" ::: 'Table (
195+ '[ "pk_users" ::: 'PrimaryKey '["id"] ] :=>
196+ '[ "id" ::: 'Def :=> 'NotNull 'PGint4
197+ , "name" ::: 'NoDef :=> 'NotNull 'PGtext
198+ ])
199+ , "emails" ::: 'Table (
200+ '[ "pk_emails" ::: 'PrimaryKey '["id"]
201+ , "fk_user_id" ::: 'ForeignKey '["user_id"] "users" '["id"]
202+ ] :=>
203+ '[ "id" ::: 'Def :=> 'NotNull 'PGint4
204+ , "user_id" ::: 'NoDef :=> 'NotNull 'PGint4
205+ , "email" ::: 'NoDef :=> 'Null 'PGtext
206+ ])
207+ ]
208+:}
209+
210+>>> :{
211+let
212+ setup :: Definition (Public '[]) (Public Schema)
213+ setup =
214+ createTable #users
215+ ( serial `as` #id :*
216+ (text & notNullable) `as` #name )
217+ ( primaryKey #id `as` #pk_users ) >>>
218+ createTable #emails
219+ ( serial `as` #id :*
220+ (int & notNullable) `as` #user_id :*
221+ (text & nullable) `as` #email )
222+ ( primaryKey #id `as` #pk_emails :*
223+ foreignKey #user_id #users #id
224+ OnDeleteCascade OnUpdateCascade `as` #fk_user_id )
225+in printSQL setup
226+:}
227+CREATE TABLE "users" ("id" serial, "name" text NOT NULL, CONSTRAINT "pk_users" PRIMARY KEY ("id"));
228+CREATE TABLE "emails" ("id" serial, "user_id" int NOT NULL, "email" text NULL, CONSTRAINT "pk_emails" PRIMARY KEY ("id"), CONSTRAINT "fk_user_id" FOREIGN KEY ("user_id") REFERENCES "users" ("id") ON DELETE CASCADE ON UPDATE CASCADE);
229+
230+A `foreignKey` can even be a table self-reference.
231+
232+>>> :{
233+type Schema =
234+ '[ "employees" ::: 'Table (
235+ '[ "employees_pk" ::: 'PrimaryKey '["id"]
236+ , "employees_employer_fk" ::: 'ForeignKey '["employer_id"] "employees" '["id"]
237+ ] :=>
238+ '[ "id" ::: 'Def :=> 'NotNull 'PGint4
239+ , "name" ::: 'NoDef :=> 'NotNull 'PGtext
240+ , "employer_id" ::: 'NoDef :=> 'Null 'PGint4
241+ ])
242+ ]
243+:}
244+
245+>>> :{
246+let
247+ setup :: Definition (Public '[]) (Public Schema)
248+ setup =
249+ createTable #employees
250+ ( serial `as` #id :*
251+ (text & notNullable) `as` #name :*
252+ (integer & nullable) `as` #employer_id )
253+ ( primaryKey #id `as` #employees_pk :*
254+ foreignKey #employer_id #employees #id
255+ OnDeleteCascade OnUpdateCascade `as` #employees_employer_fk )
256+in printSQL setup
257+:}
258+CREATE TABLE "employees" ("id" serial, "name" text NOT NULL, "employer_id" integer NULL, CONSTRAINT "employees_pk" PRIMARY KEY ("id"), CONSTRAINT "employees_employer_fk" FOREIGN KEY ("employer_id") REFERENCES "employees" ("id") ON DELETE CASCADE ON UPDATE CASCADE);
259+-}
260+foreignKey
261+ :: (ForeignKeyed schemas sch schema child parent
262+ table reftable
263+ columns refcolumns
264+ constraints cols
265+ reftys tys )
266+ => NP Alias columns
267+ -- ^ column or columns in the table
268+ -> Alias parent
269+ -- ^ reference table
270+ -> NP Alias refcolumns
271+ -- ^ reference column or columns in the reference table
272+ -> OnDeleteClause
273+ -- ^ what to do when reference is deleted
274+ -> OnUpdateClause
275+ -- ^ what to do when reference is updated
276+ -> TableConstraintExpression sch child schemas
277+ ('ForeignKey columns parent refcolumns)
278+foreignKey keys parent refs ondel onupd = UnsafeTableConstraintExpression $
279+ "FOREIGN KEY" <+> parenthesized (renderSQL keys)
280+ <+> "REFERENCES" <+> renderSQL parent
281+ <+> parenthesized (renderSQL refs)
282+ <+> renderSQL ondel
283+ <+> renderSQL onupd
284+
285+-- | A constraint synonym between types involved in a foreign key constraint.
286+type ForeignKeyed schemas
287+ sch
288+ schema
289+ child parent
290+ table reftable
291+ columns refcolumns
292+ constraints cols
293+ reftys tys =
294+ ( Has sch schemas schema
295+ , Has child schema ('Table table)
296+ , Has parent schema ('Table reftable)
297+ , HasAll columns (TableToColumns table) tys
298+ , reftable ~ (constraints :=> cols)
299+ , HasAll refcolumns cols reftys
300+ , SOP.AllZip SamePGType tys reftys
301+ , Uniquely refcolumns constraints )
302+
303+-- | `OnDeleteClause` indicates what to do with rows that reference a deleted row.
304+data OnDeleteClause
305+ = OnDeleteNoAction
306+ -- ^ if any referencing rows still exist when the constraint is checked,
307+ -- an error is raised
308+ | OnDeleteRestrict -- ^ prevents deletion of a referenced row
309+ | OnDeleteCascade
310+ -- ^ specifies that when a referenced row is deleted,
311+ -- row(s) referencing it should be automatically deleted as well
312+ deriving (GHC.Generic,Show,Eq,Ord)
313+instance NFData OnDeleteClause
314+-- | Render `OnDeleteClause`.
315+instance RenderSQL OnDeleteClause where
316+ renderSQL = \case
317+ OnDeleteNoAction -> "ON DELETE NO ACTION"
318+ OnDeleteRestrict -> "ON DELETE RESTRICT"
319+ OnDeleteCascade -> "ON DELETE CASCADE"
320+
321+-- | Analagous to `OnDeleteClause` there is also `OnUpdateClause` which is invoked
322+-- when a referenced column is changed (updated).
323+data OnUpdateClause
324+ = OnUpdateNoAction
325+ -- ^ if any referencing rows has not changed when the constraint is checked,
326+ -- an error is raised
327+ | OnUpdateRestrict -- ^ prevents update of a referenced row
328+ | OnUpdateCascade
329+ -- ^ the updated values of the referenced column(s) should be copied
330+ -- into the referencing row(s)
331+ deriving (GHC.Generic,Show,Eq,Ord)
332+instance NFData OnUpdateClause
333+
334+-- | Render `OnUpdateClause`.
335+instance RenderSQL OnUpdateClause where
336+ renderSQL = \case
337+ OnUpdateNoAction -> "ON UPDATE NO ACTION"
338+ OnUpdateRestrict -> "ON UPDATE RESTRICT"
339+ OnUpdateCascade -> "ON UPDATE CASCADE"
squeal-postgresql/src/Squeal/PostgreSQL/Definition/Type.hsnew file+229
@@ -0,0 +1,229 @@
1+{-|
2+Module: Squeal.PostgreSQL.Definition.Type
3+Description: Create and drop type definitions
4+Copyright: (c) Eitan Chatav, 2017
5+Maintainer: eitan@morphism.tech
6+Stability: experimental
7+
8+Create and drop type definitions.
9+-}
10+
11+{-# LANGUAGE
12+ AllowAmbiguousTypes
13+ , ConstraintKinds
14+ , DeriveAnyClass
15+ , DeriveGeneric
16+ , DerivingStrategies
17+ , FlexibleContexts
18+ , FlexibleInstances
19+ , GADTs
20+ , LambdaCase
21+ , MultiParamTypeClasses
22+ , OverloadedLabels
23+ , OverloadedStrings
24+ , RankNTypes
25+ , ScopedTypeVariables
26+ , TypeApplications
27+ , TypeInType
28+ , TypeOperators
29+ , UndecidableSuperClasses
30+#-}
31+
32+module Squeal.PostgreSQL.Definition.Type
33+ ( createTypeEnum
34+ , createTypeEnumFrom
35+ , createTypeComposite
36+ , createTypeCompositeFrom
37+ , createTypeRange
38+ , createDomain
39+ , dropType
40+ , dropTypeIfExists
41+ ) where
42+
43+import Data.ByteString
44+import Data.Monoid
45+import GHC.TypeLits
46+import Prelude hiding ((.), id)
47+
48+import qualified Generics.SOP as SOP
49+
50+import Squeal.PostgreSQL.Alias
51+import Squeal.PostgreSQL.Expression.Logic
52+import Squeal.PostgreSQL.Expression.Type
53+import Squeal.PostgreSQL.Definition
54+import Squeal.PostgreSQL.List
55+import Squeal.PostgreSQL.PG
56+import Squeal.PostgreSQL.Render
57+import Squeal.PostgreSQL.Schema
58+
59+-- $setup
60+-- >>> import Squeal.PostgreSQL
61+-- >>> import qualified GHC.Generics as GHC
62+-- >>> import qualified Generics.SOP as SOP
63+
64+-- | Enumerated types are created using the `createTypeEnum` command, for example
65+--
66+-- >>> printSQL $ (createTypeEnum #mood (label @"sad" :* label @"ok" :* label @"happy") :: Definition (Public '[]) '["public" ::: '["mood" ::: 'Typedef ('PGenum '["sad","ok","happy"])]])
67+-- CREATE TYPE "mood" AS ENUM ('sad', 'ok', 'happy');
68+createTypeEnum
69+ :: (KnownSymbol enum, Has sch schemas schema, SOP.All KnownSymbol labels)
70+ => QualifiedAlias sch enum
71+ -- ^ name of the user defined enumerated type
72+ -> NP PGlabel labels
73+ -- ^ labels of the enumerated type
74+ -> Definition schemas (Alter sch (Create enum ('Typedef ('PGenum labels)) schema) schemas)
75+createTypeEnum enum labels = UnsafeDefinition $
76+ "CREATE" <+> "TYPE" <+> renderSQL enum <+> "AS" <+> "ENUM" <+>
77+ parenthesized (renderSQL labels) <> ";"
78+
79+-- | Enumerated types can also be generated from a Haskell type, for example
80+--
81+-- >>> data Schwarma = Beef | Lamb | Chicken deriving GHC.Generic
82+-- >>> instance SOP.Generic Schwarma
83+-- >>> instance SOP.HasDatatypeInfo Schwarma
84+-- >>> :{
85+-- let
86+-- createSchwarma :: Definition (Public '[]) '["public" ::: '["schwarma" ::: 'Typedef (PG (Enumerated Schwarma))]]
87+-- createSchwarma = createTypeEnumFrom @Schwarma #schwarma
88+-- in
89+-- printSQL createSchwarma
90+-- :}
91+-- CREATE TYPE "schwarma" AS ENUM ('Beef', 'Lamb', 'Chicken');
92+createTypeEnumFrom
93+ :: forall hask sch enum schemas schema.
94+ ( SOP.Generic hask
95+ , SOP.All KnownSymbol (LabelsPG hask)
96+ , KnownSymbol enum
97+ , Has sch schemas schema )
98+ => QualifiedAlias sch enum
99+ -- ^ name of the user defined enumerated type
100+ -> Definition schemas (Alter sch (Create enum ('Typedef (PG (Enumerated hask))) schema) schemas)
101+createTypeEnumFrom enum = createTypeEnum enum
102+ (SOP.hpure label :: NP PGlabel (LabelsPG hask))
103+
104+{- | `createTypeComposite` creates a composite type. The composite type is
105+specified by a list of attribute names and data types.
106+
107+>>> :{
108+type PGcomplex = 'PGcomposite
109+ '[ "real" ::: 'NotNull 'PGfloat8
110+ , "imaginary" ::: 'NotNull 'PGfloat8 ]
111+:}
112+
113+>>> :{
114+let
115+ setup :: Definition (Public '[]) '["public" ::: '["complex" ::: 'Typedef PGcomplex]]
116+ setup = createTypeComposite #complex
117+ (float8 `as` #real :* float8 `as` #imaginary)
118+in printSQL setup
119+:}
120+CREATE TYPE "complex" AS ("real" float8, "imaginary" float8);
121+-}
122+createTypeComposite
123+ :: (KnownSymbol ty, Has sch schemas schema, SOP.SListI fields)
124+ => QualifiedAlias sch ty
125+ -- ^ name of the user defined composite type
126+ -> NP (Aliased (TypeExpression schemas)) fields
127+ -- ^ list of attribute names and data types
128+ -> Definition schemas (Alter sch (Create ty ('Typedef ('PGcomposite fields)) schema) schemas)
129+createTypeComposite ty fields = UnsafeDefinition $
130+ "CREATE" <+> "TYPE" <+> renderSQL ty <+> "AS" <+> parenthesized
131+ (renderCommaSeparated renderField fields) <> ";"
132+ where
133+ renderField :: Aliased (TypeExpression schemas) x -> ByteString
134+ renderField (typ `As` alias) =
135+ renderSQL alias <+> renderSQL typ
136+
137+-- | Composite types can also be generated from a Haskell type, for example
138+--
139+-- >>> data Complex = Complex {real :: Double, imaginary :: Double} deriving GHC.Generic
140+-- >>> instance SOP.Generic Complex
141+-- >>> instance SOP.HasDatatypeInfo Complex
142+-- >>> type Schema = '["complex" ::: 'Typedef (PG (Composite Complex))]
143+-- >>> :{
144+-- let
145+-- createComplex :: Definition (Public '[]) (Public Schema)
146+-- createComplex = createTypeCompositeFrom @Complex #complex
147+-- in
148+-- printSQL createComplex
149+-- :}
150+-- CREATE TYPE "complex" AS ("real" float8, "imaginary" float8);
151+createTypeCompositeFrom
152+ :: forall hask sch ty schemas schema.
153+ ( SOP.All (FieldTyped schemas) (RowPG hask)
154+ , KnownSymbol ty
155+ , Has sch schemas schema )
156+ => QualifiedAlias sch ty
157+ -- ^ name of the user defined composite type
158+ -> Definition schemas (Alter sch (Create ty ( 'Typedef (PG (Composite hask))) schema) schemas)
159+createTypeCompositeFrom ty = createTypeComposite ty
160+ (SOP.hcpure (SOP.Proxy :: SOP.Proxy (FieldTyped schemas)) fieldtype
161+ :: NP (Aliased (TypeExpression schemas)) (RowPG hask))
162+
163+{-|
164+`createDomain` creates a new domain. A domain is essentially a data type
165+with constraints (restrictions on the allowed set of values).
166+
167+Domains are useful for abstracting common constraints on fields
168+into a single location for maintenance. For example, several tables might
169+contain email address columns, all requiring the same `check` constraint
170+to verify the address syntax. Define a domain rather than setting up
171+each table's constraint individually.
172+
173+>>> :{
174+let
175+ createPositive :: Definition (Public '[]) (Public '["positive" ::: 'Typedef 'PGfloat4])
176+ createPositive = createDomain #positive real (#value .> 0 .&& (#value & isNotNull))
177+in printSQL createPositive
178+:}
179+CREATE DOMAIN "positive" AS real CHECK ((("value" > 0) AND "value" IS NOT NULL));
180+-}
181+createDomain
182+ :: (Has sch schemas schema, KnownSymbol dom)
183+ => QualifiedAlias sch dom
184+ -> (forall null. TypeExpression schemas (null ty))
185+ -> (forall tab. Condition '[] '[] 'Ungrouped schemas '[] '[tab ::: '["value" ::: 'Null ty]])
186+ -> Definition schemas (Alter sch (Create dom ('Typedef ty) schema) schemas)
187+createDomain dom ty condition =
188+ UnsafeDefinition $ "CREATE DOMAIN" <+> renderSQL dom
189+ <+> "AS" <+> renderTypeExpression ty
190+ <+> "CHECK" <+> parenthesized (renderSQL condition) <> ";"
191+
192+{- |
193+>>> :{
194+let
195+ createSmallIntRange :: Definition (Public '[]) (Public '["int2range" ::: 'Typedef ('PGrange 'PGint2)])
196+ createSmallIntRange = createTypeRange #int2range int2
197+in printSQL createSmallIntRange
198+:}
199+CREATE TYPE "int2range" AS RANGE (subtype = int2);
200+-}
201+createTypeRange
202+ :: (Has sch schemas schema, KnownSymbol range)
203+ => QualifiedAlias sch range
204+ -> (forall null. TypeExpression schemas (null ty))
205+ -> Definition schemas (Alter sch (Create range ('Typedef ('PGrange ty)) schema) schemas)
206+createTypeRange range ty = UnsafeDefinition $
207+ "CREATE" <+> "TYPE" <+> renderSQL range <+> "AS" <+> "RANGE" <+>
208+ parenthesized ("subtype" <+> "=" <+> renderTypeExpression ty) <> ";"
209+
210+-- | Drop a type.
211+--
212+-- >>> data Schwarma = Beef | Lamb | Chicken deriving GHC.Generic
213+-- >>> instance SOP.Generic Schwarma
214+-- >>> instance SOP.HasDatatypeInfo Schwarma
215+-- >>> printSQL (dropType #schwarma :: Definition '["public" ::: '["schwarma" ::: 'Typedef (PG (Enumerated Schwarma))]] (Public '[]))
216+-- DROP TYPE "schwarma";
217+dropType
218+ :: (Has sch schemas schema, KnownSymbol td)
219+ => QualifiedAlias sch td
220+ -- ^ name of the user defined type
221+ -> Definition schemas (Alter sch (DropSchemum td 'Typedef schema) schemas)
222+dropType tydef = UnsafeDefinition $ "DROP" <+> "TYPE" <+> renderSQL tydef <> ";"
223+
224+dropTypeIfExists
225+ :: (Has sch schemas schema, KnownSymbol td)
226+ => QualifiedAlias sch td
227+ -- ^ name of the user defined type
228+ -> Definition schemas (Alter sch (DropSchemumIfExists td 'Typedef schema) schemas)
229+dropTypeIfExists tydef = UnsafeDefinition $ "DROP" <+> "TYPE" <+> renderSQL tydef <> ";"
squeal-postgresql/src/Squeal/PostgreSQL/Definition/View.hsnew file+104
@@ -0,0 +1,104 @@
1+{-|
2+Module: Squeal.PostgreSQL.Definition.View
3+Description: Create and drop view definitions
4+Copyright: (c) Eitan Chatav, 2017
5+Maintainer: eitan@morphism.tech
6+Stability: experimental
7+
8+Create and drop view definitions.
9+-}
10+
11+{-# LANGUAGE
12+ AllowAmbiguousTypes
13+ , ConstraintKinds
14+ , DeriveAnyClass
15+ , DeriveGeneric
16+ , DerivingStrategies
17+ , FlexibleContexts
18+ , FlexibleInstances
19+ , GADTs
20+ , LambdaCase
21+ , MultiParamTypeClasses
22+ , OverloadedLabels
23+ , OverloadedStrings
24+ , RankNTypes
25+ , ScopedTypeVariables
26+ , TypeApplications
27+ , TypeInType
28+ , TypeOperators
29+ , UndecidableSuperClasses
30+#-}
31+
32+module Squeal.PostgreSQL.Definition.View
33+ ( createView
34+ , createOrReplaceView
35+ , dropView
36+ , dropViewIfExists
37+ ) where
38+
39+import GHC.TypeLits
40+
41+import Squeal.PostgreSQL.Alias
42+import Squeal.PostgreSQL.Definition
43+import Squeal.PostgreSQL.Query
44+import Squeal.PostgreSQL.Render
45+import Squeal.PostgreSQL.Schema
46+
47+-- $setup
48+-- >>> import Squeal.PostgreSQL
49+
50+{- | Create a view.
51+>>> type ABC = '["a" ::: 'NoDef :=> 'Null 'PGint4, "b" ::: 'NoDef :=> 'Null 'PGint4, "c" ::: 'NoDef :=> 'Null 'PGint4]
52+>>> type BC = '["b" ::: 'Null 'PGint4, "c" ::: 'Null 'PGint4]
53+>>> :{
54+let
55+ definition :: Definition
56+ '[ "public" ::: '["abc" ::: 'Table ('[] :=> ABC)]]
57+ '[ "public" ::: '["abc" ::: 'Table ('[] :=> ABC), "bc" ::: 'View BC]]
58+ definition =
59+ createView #bc (select_ (#b :* #c) (from (table #abc)))
60+in printSQL definition
61+:}
62+CREATE VIEW "bc" AS SELECT "b" AS "b", "c" AS "c" FROM "abc" AS "abc";
63+-}
64+createView
65+ :: (Has sch schemas schema, KnownSymbol vw)
66+ => QualifiedAlias sch vw -- ^ the name of the view to add
67+ -> Query '[] '[] schemas '[] view -- ^ query
68+ -> Definition schemas (Alter sch (Create vw ('View view) schema) schemas)
69+createView alias query = UnsafeDefinition $
70+ "CREATE" <+> "VIEW" <+> renderSQL alias <+> "AS"
71+ <+> renderQuery query <> ";"
72+
73+createOrReplaceView
74+ :: (Has sch schemas schema, KnownSymbol vw)
75+ => QualifiedAlias sch vw -- ^ the name of the view to add
76+ -> Query '[] '[] schemas '[] view -- ^ query
77+ -> Definition schemas (Alter sch (CreateOrReplace vw ('View view) schema) schemas)
78+createOrReplaceView alias query = UnsafeDefinition $
79+ "CREATE OR REPLACE VIEW" <+> renderSQL alias <+> "AS"
80+ <+> renderQuery query <> ";"
81+
82+-- | Drop a view.
83+--
84+-- >>> :{
85+-- let
86+-- definition :: Definition
87+-- '[ "public" ::: '["abc" ::: 'Table ('[] :=> '["a" ::: 'NoDef :=> 'Null 'PGint4, "b" ::: 'NoDef :=> 'Null 'PGint4, "c" ::: 'NoDef :=> 'Null 'PGint4])
88+-- , "bc" ::: 'View ('["b" ::: 'Null 'PGint4, "c" ::: 'Null 'PGint4])]]
89+-- '[ "public" ::: '["abc" ::: 'Table ('[] :=> '["a" ::: 'NoDef :=> 'Null 'PGint4, "b" ::: 'NoDef :=> 'Null 'PGint4, "c" ::: 'NoDef :=> 'Null 'PGint4])]]
90+-- definition = dropView #bc
91+-- in printSQL definition
92+-- :}
93+-- DROP VIEW "bc";
94+dropView
95+ :: (Has sch schemas schema, KnownSymbol vw)
96+ => QualifiedAlias sch vw -- ^ view to remove
97+ -> Definition schemas (Alter sch (DropSchemum vw 'View schema) schemas)
98+dropView vw = UnsafeDefinition $ "DROP VIEW" <+> renderSQL vw <> ";"
99+
100+dropViewIfExists
101+ :: (Has sch schemas schema, KnownSymbol vw)
102+ => QualifiedAlias sch vw -- ^ view to remove
103+ -> Definition schemas (Alter sch (DropIfExists vw schema) schemas)
104+dropViewIfExists vw = UnsafeDefinition $ "DROP VIEW IF EXISTS" <+> renderSQL vw <> ";"
squeal-postgresql/src/Squeal/PostgreSQL/Expression.hs+365−990
@@ -1,19 +1,17 @@
11{-|
2−Module: Squeal.PostgreSQL.Query
2+Module: Squeal.PostgreSQL.Expression
33Description: Squeal expressions
4−Copyright: (c) Eitan Chatav, 2017
4+Copyright: (c) Eitan Chatav, 2019
55Maintainer: eitan@morphism.tech
66Stability: experimental
77
88Squeal expressions are the atoms used to build statements.
99-}
1010
11−{-# OPTIONS_GHC -fno-warn-redundant-constraints #-}
1211{-# LANGUAGE
1312 AllowAmbiguousTypes
14− , DataKinds
13+ , ConstraintKinds
1514 , DeriveGeneric
16− , DeriveDataTypeable
1715 , FlexibleContexts
1816 , FlexibleInstances
1917 , FunctionalDependencies
@@ -22,8 +20,6 @@ Squeal expressions are the atoms used to build statements.
2220 , LambdaCase
2321 , MagicHash
2422 , OverloadedStrings
25− , PolyKinds
26− , RankNTypes
2723 , ScopedTypeVariables
2824 , StandaloneDeriving
2925 , TypeApplications
@@ -31,390 +27,356 @@ Squeal expressions are the atoms used to build statements.
3127 , TypeInType
3228 , TypeOperators
3329 , UndecidableInstances
30+ , RankNTypes
3431#-}
3532
36−module Squeal.PostgreSQL.Expression
33+module Squeal.PostgreSQL.Expression
3734 ( -- * Expression
38− Expression (UnsafeExpression, renderExpression)
39− , HasParameter (param)
40− , GroupedBy (getGroup1, getGroup2)
41− -- ** Null
42− , null_
43− , unNull
44− , coalesce
45− , fromNull
46− , isNull
47− , isn'tNull
48− , matchNull
49− , nullIf
50− -- ** Functions
51− , unsafeBinaryOp
52− , unsafeUnaryOp
35+ Expression (..)
36+ , Expr
37+ , type (-->)
38+ , FunctionDB
5339 , unsafeFunction
54− , atan2_
55− , cast
56− , quot_
57− , rem_
58− , trunc
59− , round_
60− , ceiling_
61− , greatest
62− , least
63− -- ** Conditions
64− , Condition
65− , true
66− , false
67− , not_
68− , (.&&)
69− , (.||)
70− , caseWhenThenElse
71− , ifThenElse
72− , (.==)
73− , (./=)
74− , (.>=)
75− , (.<)
76− , (.<=)
77− , (.>)
78− -- ** Time
79− , currentDate
80− , currentTime
81− , currentTimestamp
82− , localTime
83− , localTimestamp
84− -- ** Text
85− , lower
86− , upper
87− , charLength
88− , like
89− -- ** Aggregation
90− , unsafeAggregate, unsafeAggregateDistinct
91− , sum_, sumDistinct
92− , PGAvg (avg, avgDistinct)
93− , bitAnd, bitOr, boolAnd, boolOr
94− , bitAndDistinct, bitOrDistinct, boolAndDistinct, boolOrDistinct
95− , countStar
96− , count, countDistinct
97− , every, everyDistinct
98− , max_, maxDistinct, min_, minDistinct
99− -- * Tables
100− , Table (UnsafeTable, renderTable)
101− , TypeExpression (UnsafeTypeExpression, renderTypeExpression)
102− , PGTyped (pgtype)
103− , bool
104− , int2
105− , smallint
106− , int4
107− , int
108− , integer
109− , int8
110− , bigint
111− , numeric
112− , float4
113− , real
114− , float8
115− , doublePrecision
116− , serial2
117− , smallserial
118− , serial4
119− , serial
120− , serial8
121− , bigserial
122− , text
123− , char
124− , character
125− , varchar
126− , characterVarying
127− , bytea
128− , timestamp
129− , timestampWithTimeZone
130− , date
131− , time
132− , timeWithTimeZone
133− , interval
134− , uuid
135− , inet
136− , json
137− , jsonb
138− , notNull
139− , default_
40+ , function
41+ , unsafeLeftOp
42+ , leftOp
43+ , unsafeRightOp
44+ , rightOp
45+ , Operator
46+ , OperatorDB
47+ , unsafeBinaryOp
48+ , binaryOp
49+ , FunctionVar
50+ , unsafeFunctionVar
51+ , type (--->)
52+ , FunctionNDB
53+ , unsafeFunctionN
54+ , functionN
55+ , PGSubset (..)
56+ , PGIntersect (..)
14057 -- * Re-export
14158 , (&)
142− , NP ((:*), Nil)
59+ , K (..)
60+ , unK
14361 ) where
14462
14563import Control.Category
14664import Control.DeepSeq
14765import Data.ByteString (ByteString)
14866import Data.Function ((&))
149−import Data.Monoid hiding (All)
150−import Data.Ratio
67+import Data.Semigroup hiding (All)
15168import Data.String
152−import Generics.SOP hiding (from)
69+import Generics.SOP hiding (All, from)
15370import GHC.OverloadedLabels
15471import GHC.TypeLits
72+import Numeric
15573import Prelude hiding (id, (.))
15674
15775import qualified GHC.Generics as GHC
15876
159−import Squeal.PostgreSQL.Prettyprint
77+import Squeal.PostgreSQL.Alias
78+import Squeal.PostgreSQL.List
79+import Squeal.PostgreSQL.Render
16080import Squeal.PostgreSQL.Schema
16181
82+-- $setup
83+-- >>> import Squeal.PostgreSQL
84+
16285{-----------------------------------------
16386column expressions
16487-----------------------------------------}
16588
16689{- | `Expression`s are used in a variety of contexts,
167−such as in the target list of the `select` command,
168−as new column values in `insertInto` or `update`,
169−or in search `Condition`s in a number of commands.
90+such as in the target `Squeal.PostgreSQL.Query.List` of the
91+`Squeal.PostgreSQL.Query.select` command,
92+as new column values in `Squeal.PostgreSQL.Manipulation.insertRow` or
93+`Squeal.PostgreSQL.Manipulation.update`,
94+or in search `Squeal.PostgreSQL.Logic.Condition`s in a number of commands.
17095
17196The expression syntax allows the calculation of
17297values from primitive expression using arithmetic, logical,
17398and other operations.
99+
100+The type parameters of `Expression` are
101+
102+* @outer :: @ `FromType`, the @from@ clauses of any outer queries in which
103+ the `Expression` is a correlated subquery expression;
104+* @commons :: @ `FromType`, the `Squeal.PostgreSQL.Query.CommonTableExpression`s
105+ that are in scope for the `Expression`;
106+* @grp :: @ `Grouping`, the `Grouping` of the @from@ clause which may limit
107+ which columns may be referenced by alias;
108+* @schemas :: @ `SchemasType`, the schemas of your database that are in
109+ scope for the `Expression`;
110+* @from :: @ `FromType`, the @from@ clause which the `Expression` may use
111+ to reference columns by alias;
112+* @ty :: @ `NullityType`, the type of the `Expression`.
174113-}
175114newtype Expression
176− (relation :: RelationsType)
177− (grouping :: Grouping)
115+ (outer :: FromType)
116+ (commons :: FromType)
117+ (grp :: Grouping)
118+ (schemas :: SchemasType)
178119 (params :: [NullityType])
120+ (from :: FromType)
179121 (ty :: NullityType)
180122 = UnsafeExpression { renderExpression :: ByteString }
181123 deriving (GHC.Generic,Show,Eq,Ord,NFData)
182−
183−{- | A `HasParameter` constraint is used to indicate a value that is
184−supplied externally to a SQL statement.
185−`Squeal.PostgreSQL.PQ.manipulateParams`,
186−`Squeal.PostgreSQL.PQ.queryParams` and
187−`Squeal.PostgreSQL.PQ.traversePrepared` support specifying data values
188−separately from the SQL command string, in which case `param`s are used to
189−refer to the out-of-line data values.
124+instance RenderSQL (Expression outer commons grp schemas params from ty) where
125+ renderSQL = renderExpression
126+
127+-- | An `Expr` is a closed `Expression`.
128+-- It is a F@RankNType@ but don't be scared.
129+-- Think of it as an expression which sees no
130+-- namespaces, so you can't use parameters
131+-- or alias references. It can be used as
132+-- a simple piece of more complex `Expression`s.
133+type Expr x
134+ = forall outer commons grp schemas params from
135+ . Expression outer commons grp schemas params from x
136+ -- ^ cannot reference aliases
137+
138+-- | A @RankNType@ for binary operators.
139+type Operator x1 x2 y
140+ = forall outer commons grp schemas params from
141+ . Expression outer commons grp schemas params from x1
142+ -- ^ left input
143+ -> Expression outer commons grp schemas params from x2
144+ -- ^ right input
145+ -> Expression outer commons grp schemas params from y
146+ -- ^ output
147+
148+type OperatorDB schemas x1 x2 y
149+ = forall outer commons grp params from
150+ . Expression outer commons grp schemas params from x1
151+ -- ^ left input
152+ -> Expression outer commons grp schemas params from x2
153+ -- ^ right input
154+ -> Expression outer commons grp schemas params from y
155+ -- ^ output
156+
157+-- | A @RankNType@ for functions with a single argument.
158+-- These could be either function calls or unary operators.
159+-- This is a subtype of the usual Haskell function type `Prelude.->`,
160+-- indeed a subcategory as it is closed under the usual
161+-- `Prelude..` and `Prelude.id`.
162+type (-->) x y
163+ = forall outer commons grp schemas params from
164+ . Expression outer commons grp schemas params from x
165+ -- ^ input
166+ -> Expression outer commons grp schemas params from y
167+ -- ^ output
168+
169+type FunctionDB schemas x y
170+ = forall outer commons grp params from
171+ . Expression outer commons grp schemas params from x
172+ -- ^ input
173+ -> Expression outer commons grp schemas params from y
174+ -- ^ output
175+
176+{- | A @RankNType@ for functions with a fixed-length list of heterogeneous arguments.
177+Use the `*:` operator to end your argument lists, like so.
178+
179+>>> printSQL (unsafeFunctionN "fun" (true :* false :* localTime *: true))
180+fun(TRUE, FALSE, LOCALTIME, TRUE)
190181-}
191−class (PGTyped (PGTypeOf ty), KnownNat n) => HasParameter
192− (n :: Nat)
193− (params :: [NullityType])
194− (ty :: NullityType)
195− | n params -> ty where
196− param :: Expression tables grouping params ty
197− param = UnsafeExpression $ parenthesized $
198− "$" <> renderNat (Proxy @n) <+> "::"
199− <+> renderTypeExpression (pgtype @(PGTypeOf ty))
200−instance {-# OVERLAPPING #-} PGTyped (PGTypeOf ty1)
201− => HasParameter 1 (ty1:tys) ty1
202−instance {-# OVERLAPPABLE #-} (KnownNat n, HasParameter (n-1) params ty)
203− => HasParameter n (ty' : params) ty
204−
205−instance (HasUnique table tables columns, Has column columns ty)
206− => IsLabel column (Expression tables 'Ungrouped params ty) where
207− fromLabel = UnsafeExpression $ renderAlias (Alias @column)
208−
209−instance (Has table tables columns, Has column columns ty)
210− => IsTableColumn table column (Expression tables 'Ungrouped params ty) where
211− table ! column = UnsafeExpression $
212− renderAlias table <> "." <> renderAlias column
213−
214−-- | A `Column` is a witness to a `HasColumn` constraint. It's used
215−-- in `Squeel.PostgreSQL.Definition.unique` and other
216−-- `Squeel.PostgreSQL.Definition.TableConstraint`s to witness a
217−-- subcolumns relationship.
218−-- data Column
219−-- (columns :: RelationType)
220−-- (columnty :: (Symbol,NullityType))
221−-- where
222−-- Column
223−-- :: Has column columns ty
224−-- => Alias column
225−-- -> Column columns (column ::: ty)
226−-- deriving instance Show (Column columns columnty)
227−-- deriving instance Eq (Column columns columnty)
228−-- deriving instance Ord (Column columns columnty)
229−
230−-- -- | Render a `Column`.
231−-- renderColumn :: Column columns columnty -> ByteString
232−-- renderColumn (Column column) = renderAlias column
233−
234−{- | A `GroupedBy` constraint indicates that a table qualified column is
235−a member of the auxiliary namespace created by @GROUP BY@ clauses and thus,
236−may be called in an output `Expression` without aggregating.
182+type (--->) xs y
183+ = forall outer commons grp schemas params from
184+ . NP (Expression outer commons grp schemas params from) xs
185+ -- ^ inputs
186+ -> Expression outer commons grp schemas params from y
187+ -- ^ output
188+
189+type FunctionNDB schemas xs y
190+ = forall outer commons grp params from
191+ . NP (Expression outer commons grp schemas params from) xs
192+ -- ^ inputs
193+ -> Expression outer commons grp schemas params from y
194+ -- ^ output
195+
196+{- | A @RankNType@ for functions with a variable-length list of
197+homogeneous arguments and at least 1 more argument.
237198-}
238−class (KnownSymbol table, KnownSymbol column)
239− => GroupedBy table column bys where
240− getGroup1
241− :: (HasUnique table tables columns, Has column columns ty)
242− => Alias column
243− -> Expression tables ('Grouped bys) params ty
244− getGroup1 column = UnsafeExpression $ renderAlias column
245− getGroup2
246− :: (Has table tables columns, Has column columns ty)
247− => Alias table
248− -> Alias column
249− -> Expression tables ('Grouped bys) params ty
250− getGroup2 table column = UnsafeExpression $
251− renderAlias table <> "." <> renderAlias column
252−instance {-# OVERLAPPING #-} (KnownSymbol table, KnownSymbol column)
253− => GroupedBy table column ('(table,column) ': bys)
254−instance {-# OVERLAPPABLE #-}
255− ( KnownSymbol table
256− , KnownSymbol column
257− , GroupedBy table column bys
258− ) => GroupedBy table column (tabcol ': bys)
259−
199+type FunctionVar x0 x1 y
200+ = forall outer commons grp schemas params from
201+ . [Expression outer commons grp schemas params from x0]
202+ -- ^ inputs
203+ -> Expression outer commons grp schemas params from x1
204+ -- ^ must have at least 1 input
205+ -> Expression outer commons grp schemas params from y
206+ -- ^ output
207+
208+{- | >>> printSQL (unsafeFunctionVar "greatest" [true, null_] false)
209+greatest(TRUE, NULL, FALSE)
210+-}
211+unsafeFunctionVar :: ByteString -> FunctionVar x0 x1 y
212+unsafeFunctionVar fun xs x = UnsafeExpression $ fun <> parenthesized
213+ (commaSeparated (renderSQL <$> xs) <> ", " <> renderSQL x)
214+
215+instance (HasUnique tab (Join outer from) row, Has col row ty)
216+ => IsLabel col (Expression outer commons 'Ungrouped schemas params from ty) where
217+ fromLabel = UnsafeExpression $ renderSQL (Alias @col)
218+instance (HasUnique tab (Join outer from) row, Has col row ty, tys ~ '[ty])
219+ => IsLabel col (NP (Expression outer commons 'Ungrouped schemas params from) tys) where
220+ fromLabel = fromLabel @col :* Nil
221+instance (HasUnique tab (Join outer from) row, Has col row ty, column ~ (col ::: ty))
222+ => IsLabel col
223+ (Aliased (Expression outer commons 'Ungrouped schemas params from) column) where
224+ fromLabel = fromLabel @col `As` Alias
225+instance (HasUnique tab (Join outer from) row, Has col row ty, columns ~ '[col ::: ty])
226+ => IsLabel col
227+ (NP (Aliased (Expression outer commons 'Ungrouped schemas params from)) columns) where
228+ fromLabel = fromLabel @col :* Nil
229+
230+instance (Has tab (Join outer from) row, Has col row ty)
231+ => IsQualified tab col (Expression outer commons 'Ungrouped schemas params from ty) where
232+ tab ! col = UnsafeExpression $
233+ renderSQL tab <> "." <> renderSQL col
234+instance (Has tab (Join outer from) row, Has col row ty, tys ~ '[ty])
235+ => IsQualified tab col (NP (Expression outer commons 'Ungrouped schemas params from) tys) where
236+ tab ! col = tab ! col :* Nil
237+instance (Has tab (Join outer from) row, Has col row ty, column ~ (col ::: ty))
238+ => IsQualified tab col
239+ (Aliased (Expression outer commons 'Ungrouped schemas params from) column) where
240+ tab ! col = tab ! col `As` col
241+instance (Has tab (Join outer from) row, Has col row ty, columns ~ '[col ::: ty])
242+ => IsQualified tab col
243+ (NP (Aliased (Expression outer commons 'Ungrouped schemas params from)) columns) where
244+ tab ! col = tab ! col :* Nil
245+
260246instance
261− ( HasUnique table tables columns
262− , Has column columns ty
263− , GroupedBy table column bys
264− ) => IsLabel column
265− (Expression tables ('Grouped bys) params ty) where
266− fromLabel = getGroup1 (Alias @column)
267−
247+ ( HasUnique tab (Join outer from) row
248+ , Has col row ty
249+ , GroupedBy tab col bys
250+ ) => IsLabel col
251+ (Expression outer commons ('Grouped bys) schemas params from ty) where
252+ fromLabel = UnsafeExpression $ renderSQL (Alias @col)
268253instance
269− ( Has table tables columns
270− , Has column columns ty
271− , GroupedBy table column bys
272− ) => IsTableColumn table column
273− (Expression tables ('Grouped bys) params ty) where (!) = getGroup2
274−
275−-- | analagous to `Nothing`
276−--
277−-- >>> renderExpression $ null_
278−-- "NULL"
279−null_ :: Expression tables grouping params ('Null ty)
280−null_ = UnsafeExpression "NULL"
281−
282−-- | analagous to `Just`
283−--
284−-- >>> renderExpression $ unNull true
285−-- "TRUE"
286−unNull
287− :: Expression tables grouping params ('NotNull ty)
288− -- ^ not @NULL@
289− -> Expression tables grouping params ('Null ty)
290−unNull = UnsafeExpression . renderExpression
291−
292−-- | return the leftmost value which is not NULL
293−--
294−-- >>> renderExpression $ coalesce [null_, unNull true] false
295−-- "COALESCE(NULL, TRUE, FALSE)"
296−coalesce
297− :: [Expression tables grouping params ('Null ty)]
298− -- ^ @NULL@s may be present
299− -> Expression tables grouping params ('NotNull ty)
300− -- ^ @NULL@ is absent
301− -> Expression tables grouping params ('NotNull ty)
302−coalesce nullxs notNullx = UnsafeExpression $
303− "COALESCE" <> parenthesized (commaSeparated
304− ((renderExpression <$> nullxs) <> [renderExpression notNullx]))
305−
306−-- | analagous to `fromMaybe` using @COALESCE@
307−--
308−-- >>> renderExpression $ fromNull true null_
309−-- "COALESCE(NULL, TRUE)"
310−fromNull
311− :: Expression tables grouping params ('NotNull ty)
312− -- ^ what to convert @NULL@ to
313− -> Expression tables grouping params ('Null ty)
314− -> Expression tables grouping params ('NotNull ty)
315−fromNull notNullx nullx = coalesce [nullx] notNullx
316−
317−-- | >>> renderExpression $ null_ & isNull
318−-- "NULL IS NULL"
319−isNull
320− :: Expression tables grouping params ('Null ty)
321− -- ^ possibly @NULL@
322− -> Condition tables grouping params
323−isNull x = UnsafeExpression $ renderExpression x <+> "IS NULL"
324−
325−-- | >>> renderExpression $ null_ & isn'tNull
326−-- "NULL IS NOT NULL"
327−isn'tNull
328− :: Expression tables grouping params ('Null ty)
329− -- ^ possibly @NULL@
330− -> Condition tables grouping params
331−isn'tNull x = UnsafeExpression $ renderExpression x <+> "IS NOT NULL"
332−
333−-- | analagous to `maybe` using @IS NULL@
334−--
335−-- >>> renderExpression $ matchNull true not_ null_
336−-- "CASE WHEN NULL IS NULL THEN TRUE ELSE (NOT NULL) END"
337−matchNull
338− :: Expression tables grouping params (nullty)
339− -- ^ what to convert @NULL@ to
340− -> ( Expression tables grouping params ('NotNull ty)
341− -> Expression tables grouping params (nullty) )
342− -- ^ function to perform when @NULL@ is absent
343− -> Expression tables grouping params ('Null ty)
344− -> Expression tables grouping params (nullty)
345−matchNull y f x = ifThenElse (isNull x) y
346− (f (UnsafeExpression (renderExpression x)))
347−
348−-- | right inverse to `fromNull`, if its arguments are equal then
349−-- `nullIf` gives @NULL@.
350−--
351−-- >>> :set -XTypeApplications -XDataKinds
352−-- >>> renderExpression @_ @_ @'[_] $ fromNull false (nullIf false (param @1))
353−-- "COALESCE(NULL IF (FALSE, ($1 :: bool)), FALSE)"
354−nullIf
355− :: Expression tables grouping params ('NotNull ty)
356− -- ^ @NULL@ is absent
357− -> Expression tables grouping params ('NotNull ty)
358− -- ^ @NULL@ is absent
359− -> Expression tables grouping params ('Null ty)
360−nullIf x y = UnsafeExpression $ "NULL IF" <+> parenthesized
361− (renderExpression x <> ", " <> renderExpression y)
362−
363−-- | >>> renderExpression @_ @_ @'[_] $ greatest currentTimestamp [param @1]
364−-- "GREATEST(CURRENT_TIMESTAMP, ($1 :: timestamp with time zone))"
365−greatest
366− :: Expression tables grouping params (nullty)
367− -- ^ needs at least 1 argument
368− -> [Expression tables grouping params (nullty)]
369− -- ^ or more
370− -> Expression tables grouping params (nullty)
371−greatest x xs = UnsafeExpression $ "GREATEST("
372− <> commaSeparated (renderExpression <$> (x:xs)) <> ")"
373−
374−-- | >>> renderExpression $ least currentTimestamp [null_]
375−-- "LEAST(CURRENT_TIMESTAMP, NULL)"
376−least
377− :: Expression tables grouping params (nullty)
378− -- ^ needs at least 1 argument
379− -> [Expression tables grouping params (nullty)]
380− -- ^ or more
381− -> Expression tables grouping params (nullty)
382−least x xs = UnsafeExpression $ "LEAST("
383− <> commaSeparated (renderExpression <$> (x:xs)) <> ")"
254+ ( HasUnique tab (Join outer from) row
255+ , Has col row ty
256+ , GroupedBy tab col bys
257+ , tys ~ '[ty]
258+ ) => IsLabel col
259+ (NP (Expression outer commons ('Grouped bys) schemas params from) tys) where
260+ fromLabel = fromLabel @col :* Nil
261+instance
262+ ( HasUnique tab (Join outer from) row
263+ , Has col row ty
264+ , GroupedBy tab col bys
265+ , column ~ (col ::: ty)
266+ ) => IsLabel col
267+ (Aliased (Expression outer commons ('Grouped bys) schemas params from) column) where
268+ fromLabel = fromLabel @col `As` Alias
269+instance
270+ ( HasUnique tab (Join outer from) row
271+ , Has col row ty
272+ , GroupedBy tab col bys
273+ , columns ~ '[col ::: ty]
274+ ) => IsLabel col
275+ (NP (Aliased (Expression outer commons ('Grouped bys) schemas params from)) columns) where
276+ fromLabel = fromLabel @col :* Nil
384277
385−-- | >>> renderExpression $ unsafeBinaryOp "OR" true false
386−-- "(TRUE OR FALSE)"
387−unsafeBinaryOp
388− :: ByteString
389− -- ^ operator
390− -> Expression tables grouping params (ty0)
391− -> Expression tables grouping params (ty1)
392− -> Expression tables grouping params (ty2)
278+instance
279+ ( Has tab (Join outer from) row
280+ , Has col row ty
281+ , GroupedBy tab col bys
282+ ) => IsQualified tab col
283+ (Expression outer commons ('Grouped bys) schemas params from ty) where
284+ tab ! col = UnsafeExpression $
285+ renderSQL tab <> "." <> renderSQL col
286+instance
287+ ( Has tab (Join outer from) row
288+ , Has col row ty
289+ , GroupedBy tab col bys
290+ , tys ~ '[ty]
291+ ) => IsQualified tab col
292+ (NP (Expression outer commons ('Grouped bys) schemas params from) tys) where
293+ tab ! col = tab ! col :* Nil
294+instance
295+ ( Has tab (Join outer from) row
296+ , Has col row ty
297+ , GroupedBy tab col bys
298+ , column ~ (col ::: ty)
299+ ) => IsQualified tab col
300+ (Aliased (Expression outer commons ('Grouped bys) schemas params from) column) where
301+ tab ! col = tab ! col `As` col
302+instance
303+ ( Has tab (Join outer from) row
304+ , Has col row ty
305+ , GroupedBy tab col bys
306+ , columns ~ '[col ::: ty]
307+ ) => IsQualified tab col
308+ (NP (Aliased (Expression outer commons ('Grouped bys) schemas params from)) columns) where
309+ tab ! col = tab ! col :* Nil
310+
311+instance (KnownSymbol label, label `In` labels) => IsPGlabel label
312+ (Expression outer commons grp schemas params from (null ('PGenum labels))) where
313+ label = UnsafeExpression $ renderSQL (PGlabel @label)
314+
315+-- | >>> printSQL $ unsafeBinaryOp "OR" true false
316+-- (TRUE OR FALSE)
317+unsafeBinaryOp :: ByteString -> Operator ty0 ty1 ty2
393318unsafeBinaryOp op x y = UnsafeExpression $ parenthesized $
394− renderExpression x <+> op <+> renderExpression y
395−
396−-- | >>> renderExpression $ unsafeUnaryOp "NOT" true
397−-- "(NOT TRUE)"
398−unsafeUnaryOp
399− :: ByteString
400− -- ^ operator
401− -> Expression tables grouping params (ty0)
402− -> Expression tables grouping params (ty1)
403−unsafeUnaryOp op x = UnsafeExpression $ parenthesized $
404− op <+> renderExpression x
405−
406−-- | >>> renderExpression $ unsafeFunction "f" true
407−-- "f(TRUE)"
408−unsafeFunction
409− :: ByteString
410− -- ^ function
411− -> Expression tables grouping params (xty)
412− -> Expression tables grouping params (yty)
319+ renderSQL x <+> op <+> renderSQL y
320+
321+binaryOp
322+ :: forall op sch schemas schema x y z.
323+ ( Has sch schemas schema
324+ , Has op schema ('Operator ('BinaryOp x y z)) )
325+ => OperatorDB schemas x y z
326+binaryOp = unsafeBinaryOp $ renderSymbol @op
327+
328+-- | >>> printSQL $ unsafeLeftOp "NOT" true
329+-- (NOT TRUE)
330+unsafeLeftOp :: ByteString -> x --> y
331+unsafeLeftOp op x = UnsafeExpression $ parenthesized $ op <+> renderSQL x
332+
333+leftOp
334+ :: forall op sch schemas schema x y.
335+ ( Has sch schemas schema
336+ , Has op schema ('Operator ('LeftOp x y)) )
337+ => FunctionDB schemas x y
338+leftOp = unsafeLeftOp $ renderSymbol @op
339+
340+-- | >>> printSQL $ true & unsafeRightOp "IS NOT TRUE"
341+-- (TRUE IS NOT TRUE)
342+unsafeRightOp :: ByteString -> x --> y
343+unsafeRightOp op x = UnsafeExpression $ parenthesized $ renderSQL x <+> op
344+
345+rightOp
346+ :: forall op sch schemas schema x y.
347+ ( Has sch schemas schema
348+ , Has op schema ('Operator ('RightOp x y)) )
349+ => FunctionDB schemas x y
350+rightOp = unsafeRightOp $ renderSymbol @op
351+
352+-- | >>> printSQL $ unsafeFunction "f" true
353+-- f(TRUE)
354+unsafeFunction :: ByteString -> x --> y
413355unsafeFunction fun x = UnsafeExpression $
414− fun <> parenthesized (renderExpression x)
415−
416−instance PGNum ty
417− => Num (Expression tables grouping params (nullity ty)) where
356+ fun <> parenthesized (renderSQL x)
357+
358+function
359+ :: (Has sch schemas schema, Has fun schema ('Function ('[x] :=> 'Returns y)))
360+ => QualifiedAlias sch fun
361+ -> FunctionDB schemas x y
362+function = unsafeFunction . renderSQL
363+
364+-- | >>> printSQL $ unsafeFunctionN "f" (currentTime :* localTimestamp :* false *: literal 'a')
365+-- f(CURRENT_TIME, LOCALTIMESTAMP, FALSE, E'a')
366+unsafeFunctionN :: SListI xs => ByteString -> xs ---> y
367+unsafeFunctionN fun xs = UnsafeExpression $
368+ fun <> parenthesized (renderCommaSeparated renderSQL xs)
369+
370+functionN
371+ :: ( Has sch schemas schema
372+ , Has fun schema ('Function (xs :=> 'Returns y))
373+ , SListI xs )
374+ => QualifiedAlias sch fun
375+ -> FunctionNDB schemas xs y
376+functionN = unsafeFunctionN . renderSQL
377+
378+instance ty `In` PGNum
379+ => Num (Expression outer commons grp schemas params from (null ty)) where
418380 (+) = unsafeBinaryOp "+"
419381 (-) = unsafeBinaryOp "-"
420382 (*) = unsafeBinaryOp "*"
@@ -425,19 +387,24 @@ instance PGNum ty
425387 . fromString
426388 . show
427389
428−instance (PGNum ty, PGFloating ty) => Fractional
429− (Expression tables grouping params (nullity ty)) where
390+instance (ty `In` PGNum, ty `In` PGFloating) => Fractional
391+ (Expression outer commons grp schemas params from (null ty)) where
430392 (/) = unsafeBinaryOp "/"
431− fromRational x = fromInteger (numerator x) / fromInteger (denominator x)
393+ fromRational
394+ = UnsafeExpression
395+ . fromString
396+ . ($ "")
397+ . showFFloat Nothing
398+ . fromRat @Double
432399
433−instance (PGNum ty, PGFloating ty) => Floating
434− (Expression tables grouping params (nullity ty)) where
400+instance (ty `In` PGNum, ty `In` PGFloating) => Floating
401+ (Expression outer commons grp schemas params from (null ty)) where
435402 pi = UnsafeExpression "pi()"
436403 exp = unsafeFunction "exp"
437404 log = unsafeFunction "ln"
438405 sqrt = unsafeFunction "sqrt"
439406 b ** x = UnsafeExpression $
440− "power(" <> renderExpression b <> ", " <> renderExpression x <> ")"
407+ "power(" <> renderSQL b <> ", " <> renderSQL x <> ")"
441408 logBase b y = log y / log b
442409 sin = unsafeFunction "sin"
443410 cos = unsafeFunction "cos"
@@ -452,646 +419,54 @@ instance (PGNum ty, PGFloating ty) => Floating
452419 acosh x = log (x + sqrt (x*x - 1))
453420 atanh x = log ((1 + x) / (1 - x)) / 2
454421
455−-- | >>> renderExpression @_ @_ @_ @(_ (_ 'PGfloat4)) $ atan2_ pi 2
456−-- "atan2(pi(), 2)"
457−atan2_
458− :: PGFloating float
459− => Expression tables grouping params (nullity float)
460− -- ^ numerator
461− -> Expression tables grouping params (nullity float)
462− -- ^ denominator
463− -> Expression tables grouping params (nullity float)
464−atan2_ y x = UnsafeExpression $
465− "atan2(" <> renderExpression y <> ", " <> renderExpression x <> ")"
466−
467−-- When a `cast` is applied to an `Expression` of a known type, it
468−-- represents a run-time type conversion. The cast will succeed only if a
469−-- suitable type conversion operation has been defined.
470−--
471−-- | >>> renderExpression $ true & cast int4
472−-- "(TRUE :: int4)"
473−cast
474− :: TypeExpression ('NoDef :=> 'Null ty1)
475− -- ^ type to cast as
476− -> Expression tables grouping params (nullity ty0)
477− -- ^ value to convert
478− -> Expression tables grouping params (nullity ty1)
479−cast ty x = UnsafeExpression $ parenthesized $
480− renderExpression x <+> "::" <+> renderTypeExpression ty
481−
482−-- | integer division, truncates the result
483−--
484−-- >>> renderExpression @_ @_ @_ @(_(_ 'PGint2)) $ 5 `quot_` 2
485−-- "(5 / 2)"
486−quot_
487− :: PGIntegral int
488− => Expression tables grouping params (nullity int)
489− -- ^ numerator
490− -> Expression tables grouping params (nullity int)
491− -- ^ denominator
492− -> Expression tables grouping params (nullity int)
493−quot_ = unsafeBinaryOp "/"
494−
495−-- | remainder upon integer division
496−--
497−-- >>> renderExpression @_ @_ @_ @(_ (_ 'PGint2)) $ 5 `rem_` 2
498−-- "(5 % 2)"
499−rem_
500− :: PGIntegral int
501− => Expression tables grouping params (nullity int)
502− -- ^ numerator
503− -> Expression tables grouping params (nullity int)
504− -- ^ denominator
505− -> Expression tables grouping params (nullity int)
506−rem_ = unsafeBinaryOp "%"
507−
508−-- | >>> renderExpression @_ @_ @_ @(_ (_ 'PGfloat4)) $ trunc pi
509−-- "trunc(pi())"
510−trunc
511− :: PGFloating frac
512− => Expression tables grouping params (nullity frac)
513− -- ^ fractional number
514− -> Expression tables grouping params (nullity frac)
515−trunc = unsafeFunction "trunc"
516−
517−-- | >>> renderExpression @_ @_ @_ @(_ (_ 'PGfloat4)) $ round_ pi
518−-- "round(pi())"
519−round_
520− :: PGFloating frac
521− => Expression tables grouping params (nullity frac)
522− -- ^ fractional number
523− -> Expression tables grouping params (nullity frac)
524−round_ = unsafeFunction "round"
525−
526−-- | >>> renderExpression @_ @_ @_ @(_ (_ 'PGfloat4)) $ ceiling_ pi
527−-- "ceiling(pi())"
528−ceiling_
529− :: PGFloating frac
530− => Expression tables grouping params (nullity frac)
531− -- ^ fractional number
532− -> Expression tables grouping params (nullity frac)
533−ceiling_ = unsafeFunction "ceiling"
534−
535−-- | A `Condition` is a boolean valued `Expression`. While SQL allows
536−-- conditions to have @NULL@, squeal instead chooses to disallow @NULL@,
537−-- forcing one to handle the case of @NULL@ explicitly to produce
538−-- a `Condition`.
539−type Condition tables grouping params =
540− Expression tables grouping params ('NotNull 'PGbool)
541−
542−-- | >>> renderExpression true
543−-- "TRUE"
544−true :: Condition tables grouping params
545−true = UnsafeExpression "TRUE"
546−
547−-- | >>> renderExpression false
548−-- "FALSE"
549−false :: Condition tables grouping params
550−false = UnsafeExpression "FALSE"
551−
552−-- | >>> renderExpression $ not_ true
553−-- "(NOT TRUE)"
554−not_
555− :: Condition tables grouping params
556− -> Condition tables grouping params
557−not_ = unsafeUnaryOp "NOT"
558−
559−-- | >>> renderExpression $ true .&& false
560−-- "(TRUE AND FALSE)"
561−(.&&)
562− :: Condition tables grouping params
563− -> Condition tables grouping params
564− -> Condition tables grouping params
565−(.&&) = unsafeBinaryOp "AND"
566−
567−-- | >>> renderExpression $ true .|| false
568−-- "(TRUE OR FALSE)"
569−(.||)
570− :: Condition tables grouping params
571− -> Condition tables grouping params
572− -> Condition tables grouping params
573−(.||) = unsafeBinaryOp "OR"
574−
575−-- | >>> renderExpression @_ @_ @_ @(_ (_ 'PGint2)) $ caseWhenThenElse [(true, 1), (false, 2)] 3
576−-- "CASE WHEN TRUE THEN 1 WHEN FALSE THEN 2 ELSE 3 END"
577−caseWhenThenElse
578− :: [ ( Condition tables grouping params
579− , Expression tables grouping params (ty)
580− ) ]
581− -> Expression tables grouping params (ty)
582− -> Expression tables grouping params (ty)
583−caseWhenThenElse whenThens else_ = UnsafeExpression $ mconcat
584− [ "CASE"
585− , mconcat
586− [ mconcat
587− [ " WHEN ", renderExpression when_
588− , " THEN ", renderExpression then_
589− ]
590− | (when_,then_) <- whenThens
591− ]
592− , " ELSE ", renderExpression else_
593− , " END"
594− ]
595−
596−-- | >>> renderExpression @_ @_ @_ @(_ (_ 'PGint2)) $ ifThenElse true 1 0
597−-- "CASE WHEN TRUE THEN 1 ELSE 0 END"
598−ifThenElse
599− :: Condition tables grouping params
600− -> Expression tables grouping params (ty)
601− -> Expression tables grouping params (ty)
602− -> Expression tables grouping params (ty)
603−ifThenElse if_ then_ else_ = caseWhenThenElse [(if_,then_)] else_
604−
605−-- | Comparison operations like `.==`, `./=`, `.>`, `.>=`, `.<` and `.<=`
606−-- will produce @NULL@s if one of their arguments is @NULL@.
607−--
608−-- >>> renderExpression $ unNull true .== null_
609−-- "(TRUE = NULL)"
610−(.==)
611− :: Expression tables grouping params (nullity ty) -- ^ lhs
612− -> Expression tables grouping params (nullity ty) -- ^ rhs
613− -> Expression tables grouping params (nullity 'PGbool)
614−(.==) = unsafeBinaryOp "="
615−infix 4 .==
616−
617−-- | >>> renderExpression $ unNull true ./= null_
618−-- "(TRUE <> NULL)"
619−(./=)
620− :: Expression tables grouping params (nullity ty) -- ^ lhs
621− -> Expression tables grouping params (nullity ty) -- ^ rhs
622− -> Expression tables grouping params (nullity 'PGbool)
623−(./=) = unsafeBinaryOp "<>"
624−infix 4 ./=
625−
626−-- | >>> renderExpression $ unNull true .>= null_
627−-- "(TRUE >= NULL)"
628−(.>=)
629− :: Expression tables grouping params (nullity ty) -- ^ lhs
630− -> Expression tables grouping params (nullity ty) -- ^ rhs
631− -> Expression tables grouping params (nullity 'PGbool)
632−(.>=) = unsafeBinaryOp ">="
633−infix 4 .>=
634−
635−-- | >>> renderExpression $ unNull true .< null_
636−-- "(TRUE < NULL)"
637−(.<)
638− :: Expression tables grouping params (nullity ty) -- ^ lhs
639− -> Expression tables grouping params (nullity ty) -- ^ rhs
640− -> Expression tables grouping params (nullity 'PGbool)
641−(.<) = unsafeBinaryOp "<"
642−infix 4 .<
643−
644−-- | >>> renderExpression $ unNull true .<= null_
645−-- "(TRUE <= NULL)"
646−(.<=)
647− :: Expression tables grouping params (nullity ty) -- ^ lhs
648− -> Expression tables grouping params (nullity ty) -- ^ rhs
649− -> Expression tables grouping params (nullity 'PGbool)
650−(.<=) = unsafeBinaryOp "<="
651−infix 4 .<=
652−
653−-- | >>> renderExpression $ unNull true .> null_
654−-- "(TRUE > NULL)"
655−(.>)
656− :: Expression tables grouping params (nullity ty) -- ^ lhs
657− -> Expression tables grouping params (nullity ty) -- ^ rhs
658− -> Expression tables grouping params (nullity 'PGbool)
659−(.>) = unsafeBinaryOp ">"
660−infix 4 .>
661−
662−-- | >>> renderExpression $ currentDate
663−-- "CURRENT_DATE"
664−currentDate
665− :: Expression tables grouping params (nullity 'PGdate)
666−currentDate = UnsafeExpression "CURRENT_DATE"
667−
668−-- | >>> renderExpression $ currentTime
669−-- "CURRENT_TIME"
670−currentTime
671− :: Expression tables grouping params (nullity 'PGtimetz)
672−currentTime = UnsafeExpression "CURRENT_TIME"
673−
674−-- | >>> renderExpression $ currentTimestamp
675−-- "CURRENT_TIMESTAMP"
676−currentTimestamp
677− :: Expression tables grouping params (nullity 'PGtimestamptz)
678−currentTimestamp = UnsafeExpression "CURRENT_TIMESTAMP"
679−
680−-- | >>> renderExpression $ localTime
681−-- "LOCALTIME"
682−localTime
683− :: Expression tables grouping params (nullity 'PGtime)
684−localTime = UnsafeExpression "LOCALTIME"
685−
686−-- | >>> renderExpression $ localTimestamp
687−-- "LOCALTIMESTAMP"
688−localTimestamp
689− :: Expression tables grouping params (nullity 'PGtimestamp)
690−localTimestamp = UnsafeExpression "LOCALTIMESTAMP"
691−
692−{-----------------------------------------
693−text
694−-----------------------------------------}
422+-- | Contained by operators
423+class PGSubset ty where
424+ (@>) :: Operator (null0 ty) (null1 ty) ('Null 'PGbool)
425+ (@>) = unsafeBinaryOp "@>"
426+ (<@) :: Operator (null0 ty) (null1 ty) ('Null 'PGbool)
427+ (<@) = unsafeBinaryOp "<@"
428+instance PGSubset 'PGjsonb
429+instance PGSubset 'PGtsquery
430+instance PGSubset ('PGvararray ty)
431+instance PGSubset ('PGrange ty)
432+
433+class PGIntersect ty where
434+ (@&&) :: Operator (null0 ty) (null1 ty) ('Null 'PGbool)
435+ (@&&) = unsafeBinaryOp "&&"
436+instance PGIntersect ('PGvararray ty)
437+instance PGIntersect ('PGrange ty)
695438
696439instance IsString
697− (Expression tables grouping params (nullity 'PGtext)) where
440+ (Expression outer commons grp schemas params from (null 'PGtext)) where
698441 fromString str = UnsafeExpression $
699442 "E\'" <> fromString (escape =<< str) <> "\'"
700− where
701− escape = \case
702− '\NUL' -> "\\0"
703− '\'' -> "''"
704− '"' -> "\\\""
705− '\b' -> "\\b"
706− '\n' -> "\\n"
707− '\r' -> "\\r"
708− '\t' -> "\\t"
709− '\\' -> "\\\\"
710− c -> [c]
443+instance IsString
444+ (Expression outer commons grp schemas params from (null 'PGtsvector)) where
445+ fromString str = UnsafeExpression . parenthesized . (<> " :: tsvector") $
446+ "E\'" <> fromString (escape =<< str) <> "\'"
447+instance IsString
448+ (Expression outer commons grp schemas params from (null 'PGtsquery)) where
449+ fromString str = UnsafeExpression . parenthesized . (<> " :: tsquery") $
450+ "E\'" <> fromString (escape =<< str) <> "\'"
451+
452+instance Semigroup
453+ (Expression outer commons grp schemas params from (null ('PGvararray ty))) where
454+ (<>) = unsafeBinaryOp "||"
455+instance Semigroup
456+ (Expression outer commons grp schemas params from (null 'PGjsonb)) where
457+ (<>) = unsafeBinaryOp "||"
458+instance Semigroup
459+ (Expression outer commons grp schemas params from (null 'PGtext)) where
460+ (<>) = unsafeBinaryOp "||"
461+instance Semigroup
462+ (Expression outer commons grp schemas params from (null 'PGtsvector)) where
463+ (<>) = unsafeBinaryOp "||"
711464
712465instance Monoid
713− (Expression tables grouping params (nullity 'PGtext)) where
466+ (Expression outer commons grp schemas params from (null 'PGtext)) where
714467 mempty = fromString ""
715− mappend = unsafeBinaryOp "||"
716−
717−-- | >>> renderExpression $ lower "ARRRGGG"
718−-- "lower(E'ARRRGGG')"
719−lower
720− :: Expression tables grouping params (nullity 'PGtext)
721− -- ^ string to lower case
722− -> Expression tables grouping params (nullity 'PGtext)
723−lower = unsafeFunction "lower"
724−
725−-- | >>> renderExpression $ upper "eeee"
726−-- "upper(E'eeee')"
727−upper
728− :: Expression tables grouping params (nullity 'PGtext)
729− -- ^ string to upper case
730− -> Expression tables grouping params (nullity 'PGtext)
731−upper = unsafeFunction "upper"
732−
733−-- | >>> renderExpression $ charLength "four"
734−-- "char_length(E'four')"
735−charLength
736− :: Expression tables grouping params (nullity 'PGtext)
737− -- ^ string to measure
738− -> Expression tables grouping params (nullity 'PGint4)
739−charLength = unsafeFunction "char_length"
740−
741−-- | The `like` expression returns true if the @string@ matches
742−-- the supplied @pattern@. If @pattern@ does not contain percent signs
743−-- or underscores, then the pattern only represents the string itself;
744−-- in that case `like` acts like the equals operator. An underscore (_)
745−-- in pattern stands for (matches) any single character; a percent sign (%)
746−-- matches any sequence of zero or more characters.
747−--
748−-- >>> renderExpression $ "abc" `like` "a%"
749−-- "(E'abc' LIKE E'a%')"
750−like
751− :: Expression tables grouping params (nullity 'PGtext)
752− -- ^ string
753− -> Expression tables grouping params (nullity 'PGtext)
754− -- ^ pattern
755− -> Expression tables grouping params (nullity 'PGbool)
756−like = unsafeBinaryOp "LIKE"
757−
758−{-----------------------------------------
759−aggregation
760−-----------------------------------------}
761−
762−-- | escape hatch to define aggregate functions
763−unsafeAggregate
764− :: ByteString -- ^ aggregate function
765− -> Expression tables 'Ungrouped params (xty)
766− -> Expression tables ('Grouped bys) params (yty)
767−unsafeAggregate fun x = UnsafeExpression $ mconcat
768− [fun, "(", renderExpression x, ")"]
769−
770−-- | escape hatch to define aggregate functions over distinct values
771−unsafeAggregateDistinct
772− :: ByteString -- ^ aggregate function
773− -> Expression tables 'Ungrouped params (xty)
774− -> Expression tables ('Grouped bys) params (yty)
775−unsafeAggregateDistinct fun x = UnsafeExpression $ mconcat
776− [fun, "(DISTINCT ", renderExpression x, ")"]
777−
778−-- | >>> renderExpression @'[_ ::: '["col" ::: 'Required (_ 'PGnumeric)]] $ sum_ #col
779−-- "sum(col)"
780−sum_
781− :: PGNum ty
782− => Expression tables 'Ungrouped params (nullity ty)
783− -- ^ what to sum
784− -> Expression tables ('Grouped bys) params (nullity ty)
785−sum_ = unsafeAggregate "sum"
786−
787−-- | >>> renderExpression @'[_ ::: '["col" ::: 'Required (_ 'PGnumeric)]] $ sumDistinct #col
788−-- "sum(DISTINCT col)"
789−sumDistinct
790− :: PGNum ty
791− => Expression tables 'Ungrouped params (nullity ty)
792− -- ^ what to sum
793− -> Expression tables ('Grouped bys) params (nullity ty)
794−sumDistinct = unsafeAggregateDistinct "sum"
795−
796−-- | A constraint for `PGType`s that you can take averages of and the resulting
797−-- `PGType`.
798−class PGAvg ty avg | ty -> avg where
799− avg, avgDistinct
800− :: Expression tables 'Ungrouped params (nullity ty)
801− -- ^ what to average
802− -> Expression tables ('Grouped bys) params (nullity avg)
803− avg = unsafeAggregate "avg"
804− avgDistinct = unsafeAggregateDistinct "avg"
805−instance PGAvg 'PGint2 'PGnumeric
806−instance PGAvg 'PGint4 'PGnumeric
807−instance PGAvg 'PGint8 'PGnumeric
808−instance PGAvg 'PGnumeric 'PGnumeric
809−instance PGAvg 'PGfloat4 'PGfloat8
810−instance PGAvg 'PGfloat8 'PGfloat8
811−instance PGAvg 'PGinterval 'PGinterval
812−
813−-- | >>> renderExpression @'[_ ::: '["col" ::: 'Required (_ 'PGint4)]] $ bitAnd #col
814−-- "bit_and(col)"
815−bitAnd
816− :: PGIntegral int
817− => Expression tables 'Ungrouped params (nullity int)
818− -- ^ what to aggregate
819− -> Expression tables ('Grouped bys) params (nullity int)
820−bitAnd = unsafeAggregate "bit_and"
821−
822−-- | >>> renderExpression @'[_ ::: '["col" ::: 'Required (_ 'PGint4)]] $ bitOr #col
823−-- "bit_or(col)"
824−bitOr
825− :: PGIntegral int
826− => Expression tables 'Ungrouped params (nullity int)
827− -- ^ what to aggregate
828− -> Expression tables ('Grouped bys) params (nullity int)
829−bitOr = unsafeAggregate "bit_or"
830−
831−-- | >>> renderExpression @'[_ ::: '["col" ::: 'Required (_ 'PGint4)]] $ bitAndDistinct #col
832−-- "bit_and(DISTINCT col)"
833−bitAndDistinct
834− :: PGIntegral int
835− => Expression tables 'Ungrouped params (nullity int)
836− -- ^ what to aggregate
837− -> Expression tables ('Grouped bys) params (nullity int)
838−bitAndDistinct = unsafeAggregateDistinct "bit_and"
839−
840−-- | >>> renderExpression @'[_ ::: '["col" ::: 'Required (_ 'PGint4)]] $ bitOrDistinct #col
841−-- "bit_or(DISTINCT col)"
842−bitOrDistinct
843− :: PGIntegral int
844− => Expression tables 'Ungrouped params (nullity int)
845− -- ^ what to aggregate
846− -> Expression tables ('Grouped bys) params (nullity int)
847−bitOrDistinct = unsafeAggregateDistinct "bit_or"
848−
849−-- | >>> renderExpression @'[_ ::: '["col" ::: 'Required (_ 'PGbool)]] $ boolAnd #col
850−-- "bool_and(col)"
851−boolAnd
852− :: Expression tables 'Ungrouped params (nullity 'PGbool)
853− -- ^ what to aggregate
854− -> Expression tables ('Grouped bys) params (nullity 'PGbool)
855−boolAnd = unsafeAggregate "bool_and"
856−
857−-- | >>> renderExpression @'[_ ::: '["col" ::: 'Required (_ 'PGbool)]] $ boolOr #col
858−-- "bool_or(col)"
859−boolOr
860− :: Expression tables 'Ungrouped params (nullity 'PGbool)
861− -- ^ what to aggregate
862− -> Expression tables ('Grouped bys) params (nullity 'PGbool)
863−boolOr = unsafeAggregate "bool_or"
864−
865−-- | >>> renderExpression @'[_ ::: '["col" ::: 'Required (_ 'PGbool)]] $ boolAndDistinct #col
866−-- "bool_and(DISTINCT col)"
867−boolAndDistinct
868− :: Expression tables 'Ungrouped params (nullity 'PGbool)
869− -- ^ what to aggregate
870− -> Expression tables ('Grouped bys) params (nullity 'PGbool)
871−boolAndDistinct = unsafeAggregateDistinct "bool_and"
872−
873−-- | >>> renderExpression @'[_ ::: '["col" ::: 'Required (_ 'PGbool)]] $ boolOrDistinct #col
874−-- "bool_or(DISTINCT col)"
875−boolOrDistinct
876− :: Expression tables 'Ungrouped params (nullity 'PGbool)
877− -- ^ what to aggregate
878− -> Expression tables ('Grouped bys) params (nullity 'PGbool)
879−boolOrDistinct = unsafeAggregateDistinct "bool_or"
880−
881−-- | A special aggregation that does not require an input
882−--
883−-- >>> renderExpression countStar
884−-- "count(*)"
885−countStar
886− :: Expression tables ('Grouped bys) params ('NotNull 'PGint8)
887−countStar = UnsafeExpression $ "count(*)"
888−
889−-- | >>> renderExpression @'[_ ::: '["col" ::: 'Optional _]] $ count #col
890−-- "count(col)"
891−count
892− :: Expression tables 'Ungrouped params (ty)
893− -- ^ what to count
894− -> Expression tables ('Grouped bys) params ('NotNull 'PGint8)
895−count = unsafeAggregate "count"
896−
897−-- | >>> renderExpression @'[_ ::: '["col" ::: 'Required _]] $ countDistinct #col
898−-- "count(DISTINCT col)"
899−countDistinct
900− :: Expression tables 'Ungrouped params (ty)
901− -- ^ what to count
902− -> Expression tables ('Grouped bys) params ('NotNull 'PGint8)
903−countDistinct = unsafeAggregateDistinct "count"
904−
905−-- | synonym for `boolAnd`
906−--
907−-- >>> renderExpression @'[_ ::: '["col" ::: 'Required (_ 'PGbool)]] $ every #col
908−-- "every(col)"
909−every
910− :: Expression tables 'Ungrouped params (nullity 'PGbool)
911− -- ^ what to aggregate
912− -> Expression tables ('Grouped bys) params (nullity 'PGbool)
913−every = unsafeAggregate "every"
914−
915−-- | synonym for `boolAndDistinct`
916−--
917−-- >>> renderExpression @'[_ ::: '["col" ::: 'Required (_ 'PGbool)]] $ everyDistinct #col
918−-- "every(DISTINCT col)"
919−everyDistinct
920− :: Expression tables 'Ungrouped params (nullity 'PGbool)
921− -- ^ what to aggregate
922− -> Expression tables ('Grouped bys) params (nullity 'PGbool)
923−everyDistinct = unsafeAggregateDistinct "every"
924−
925−-- | minimum and maximum aggregation
926−max_, min_, maxDistinct, minDistinct
927− :: Expression tables 'Ungrouped params (nullity ty)
928− -- ^ what to aggregate
929− -> Expression tables ('Grouped bys) params (nullity ty)
930−max_ = unsafeAggregate "max"
931−min_ = unsafeAggregate "min"
932−maxDistinct = unsafeAggregateDistinct "max"
933−minDistinct = unsafeAggregateDistinct "min"
934−
935−{-----------------------------------------
936−tables
937−-----------------------------------------}
938−
939−-- | A `Table` from a table expression is a way
940−-- to call a table reference by its alias.
941−newtype Table
942− (schema :: TablesType)
943− (columns :: RelationType)
944− = UnsafeTable { renderTable :: ByteString }
945− deriving (GHC.Generic,Show,Eq,Ord,NFData)
946−instance
947− ( Has alias schema table
948− , relation ~ ColumnsToRelation (TableToColumns table)
949− ) => IsLabel alias (Table schema relation) where
950− fromLabel = UnsafeTable $ renderAlias (Alias @alias)
951−
952−{-----------------------------------------
953−type expressions
954−-----------------------------------------}
955−
956−-- | `TypeExpression`s are used in `cast`s and `createTable` commands.
957−newtype TypeExpression (ty :: ColumnType)
958− = UnsafeTypeExpression { renderTypeExpression :: ByteString }
959− deriving (GHC.Generic,Show,Eq,Ord,NFData)
960−
961−-- | logical Boolean (true/false)
962−bool :: TypeExpression ('NoDef :=> 'Null 'PGbool)
963−bool = UnsafeTypeExpression "bool"
964−-- | signed two-byte integer
965−int2, smallint :: TypeExpression ('NoDef :=> 'Null 'PGint2)
966−int2 = UnsafeTypeExpression "int2"
967−smallint = UnsafeTypeExpression "smallint"
968−-- | signed four-byte integer
969−int4, int, integer :: TypeExpression ('NoDef :=> 'Null 'PGint4)
970−int4 = UnsafeTypeExpression "int4"
971−int = UnsafeTypeExpression "int"
972−integer = UnsafeTypeExpression "integer"
973−-- | signed eight-byte integer
974−int8, bigint :: TypeExpression ('NoDef :=> 'Null 'PGint8)
975−int8 = UnsafeTypeExpression "int8"
976−bigint = UnsafeTypeExpression "bigint"
977−-- | arbitrary precision numeric type
978−numeric :: TypeExpression ('NoDef :=> 'Null 'PGnumeric)
979−numeric = UnsafeTypeExpression "numeric"
980−-- | single precision floating-point number (4 bytes)
981−float4, real :: TypeExpression ('NoDef :=> 'Null 'PGfloat4)
982−float4 = UnsafeTypeExpression "float4"
983−real = UnsafeTypeExpression "real"
984−-- | double precision floating-point number (8 bytes)
985−float8, doublePrecision :: TypeExpression ('NoDef :=> 'Null 'PGfloat8)
986−float8 = UnsafeTypeExpression "float8"
987−doublePrecision = UnsafeTypeExpression "double precision"
988−-- | not a true type, but merely a notational convenience for creating
989−-- unique identifier columns with type `'PGint2`
990−serial2, smallserial
991− :: TypeExpression ('Def :=> 'NotNull 'PGint2)
992−serial2 = UnsafeTypeExpression "serial2"
993−smallserial = UnsafeTypeExpression "smallserial"
994−-- | not a true type, but merely a notational convenience for creating
995−-- unique identifier columns with type `'PGint4`
996−serial4, serial
997− :: TypeExpression ('Def :=> 'NotNull 'PGint4)
998−serial4 = UnsafeTypeExpression "serial4"
999−serial = UnsafeTypeExpression "serial"
1000−-- | not a true type, but merely a notational convenience for creating
1001−-- unique identifier columns with type `'PGint8`
1002−serial8, bigserial
1003− :: TypeExpression ('Def :=> 'NotNull 'PGint8)
1004−serial8 = UnsafeTypeExpression "serial8"
1005−bigserial = UnsafeTypeExpression "bigserial"
1006−-- | variable-length character string
1007−text :: TypeExpression ('NoDef :=> 'Null 'PGtext)
1008−text = UnsafeTypeExpression "text"
1009−-- | fixed-length character string
1010−char, character
1011− :: (KnownNat n, 1 <= n)
1012− => proxy n
1013− -> TypeExpression ('NoDef :=> 'Null ('PGchar n))
1014−char p = UnsafeTypeExpression $ "char(" <> renderNat p <> ")"
1015−character p = UnsafeTypeExpression $ "character(" <> renderNat p <> ")"
1016−-- | variable-length character string
1017−varchar, characterVarying
1018− :: (KnownNat n, 1 <= n)
1019− => proxy n
1020− -> TypeExpression ('NoDef :=> 'Null ('PGvarchar n))
1021−varchar p = UnsafeTypeExpression $ "varchar(" <> renderNat p <> ")"
1022−characterVarying p = UnsafeTypeExpression $
1023− "character varying(" <> renderNat p <> ")"
1024−-- | binary data ("byte array")
1025−bytea :: TypeExpression ('NoDef :=> 'Null 'PGbytea)
1026−bytea = UnsafeTypeExpression "bytea"
1027−-- | date and time (no time zone)
1028−timestamp :: TypeExpression ('NoDef :=> 'Null 'PGtimestamp)
1029−timestamp = UnsafeTypeExpression "timestamp"
1030−-- | date and time, including time zone
1031−timestampWithTimeZone :: TypeExpression ('NoDef :=> 'Null 'PGtimestamptz)
1032−timestampWithTimeZone = UnsafeTypeExpression "timestamp with time zone"
1033−-- | calendar date (year, month, day)
1034−date :: TypeExpression ('NoDef :=> 'Null 'PGdate)
1035−date = UnsafeTypeExpression "date"
1036−-- | time of day (no time zone)
1037−time :: TypeExpression ('NoDef :=> 'Null 'PGtime)
1038−time = UnsafeTypeExpression "time"
1039−-- | time of day, including time zone
1040−timeWithTimeZone :: TypeExpression ('NoDef :=> 'Null 'PGtimetz)
1041−timeWithTimeZone = UnsafeTypeExpression "time with time zone"
1042−-- | time span
1043−interval :: TypeExpression ('NoDef :=> 'Null 'PGinterval)
1044−interval = UnsafeTypeExpression "interval"
1045−-- | universally unique identifier
1046−uuid :: TypeExpression ('NoDef :=> 'Null 'PGuuid)
1047−uuid = UnsafeTypeExpression "uuid"
1048−-- | IPv4 or IPv6 host address
1049−inet :: TypeExpression ('NoDef :=> 'Null 'PGinet)
1050−inet = UnsafeTypeExpression "inet"
1051−-- | textual JSON data
1052−json :: TypeExpression ('NoDef :=> 'Null 'PGjson)
1053−json = UnsafeTypeExpression "json"
1054−-- | binary JSON data, decomposed
1055−jsonb :: TypeExpression ('NoDef :=> 'Null 'PGjsonb)
1056−jsonb = UnsafeTypeExpression "jsonb"
1057−
1058−-- | used in `createTable` commands as a column constraint to ensure
1059−-- @NULL@ is not present
1060−notNull
1061− :: TypeExpression (constraints :=> 'Null ty)
1062− -> TypeExpression (constraints :=> 'NotNull ty)
1063−notNull ty = UnsafeTypeExpression $ renderTypeExpression ty <+> "NOT NULL"
1064−
1065−-- | used in `createTable` commands as a column constraint to give a default
1066−default_
1067− :: Expression '[] 'Ungrouped '[] ty
1068− -> TypeExpression ('NoDef :=> ty)
1069− -> TypeExpression ('Def :=> ty)
1070−default_ x ty = UnsafeTypeExpression $
1071− renderTypeExpression ty <+> "DEFAULT" <+> renderExpression x
1072−
1073−-- | `pgtype` is a demoted version of a `PGType`
1074−class PGTyped (ty :: PGType) where
1075− pgtype :: TypeExpression ('NoDef :=> 'Null ty)
1076−instance PGTyped 'PGbool where pgtype = bool
1077−instance PGTyped 'PGint2 where pgtype = int2
1078−instance PGTyped 'PGint4 where pgtype = int4
1079−instance PGTyped 'PGint8 where pgtype = int8
1080−instance PGTyped 'PGnumeric where pgtype = numeric
1081−instance PGTyped 'PGfloat4 where pgtype = float4
1082−instance PGTyped 'PGfloat8 where pgtype = float8
1083−instance PGTyped 'PGtext where pgtype = text
1084−instance (KnownNat n, 1 <= n)
1085− => PGTyped ('PGchar n) where pgtype = char (Proxy @n)
1086−instance (KnownNat n, 1 <= n)
1087− => PGTyped ('PGvarchar n) where pgtype = varchar (Proxy @n)
1088−instance PGTyped 'PGbytea where pgtype = bytea
1089−instance PGTyped 'PGtimestamp where pgtype = timestamp
1090−instance PGTyped 'PGtimestamptz where pgtype = timestampWithTimeZone
1091−instance PGTyped 'PGdate where pgtype = date
1092−instance PGTyped 'PGtime where pgtype = time
1093−instance PGTyped 'PGtimetz where pgtype = timeWithTimeZone
1094−instance PGTyped 'PGinterval where pgtype = interval
1095−instance PGTyped 'PGuuid where pgtype = uuid
1096−instance PGTyped 'PGjson where pgtype = json
1097−instance PGTyped 'PGjsonb where pgtype = jsonb
468+ mappend = (<>)
469+instance Monoid
470+ (Expression outer commons grp schemas params from (null 'PGtsvector)) where
471+ mempty = fromString ""
472+ mappend = (<>)
squeal-postgresql/src/Squeal/PostgreSQL/Expression/Aggregate.hsnew file+462
@@ -0,0 +1,462 @@
1+{-|
2+Module: Squeal.PostgreSQL.Expression.Aggregate
3+Description: Aggregate functions
4+Copyright: (c) Eitan Chatav, 2019
5+Maintainer: eitan@morphism.tech
6+Stability: experimental
7+
8+Aggregate functions
9+-}
10+
11+{-# LANGUAGE
12+ DataKinds
13+ , DeriveGeneric
14+ , FlexibleContexts
15+ , FlexibleInstances
16+ , FunctionalDependencies
17+ , LambdaCase
18+ , MultiParamTypeClasses
19+ , OverloadedStrings
20+ , PolyKinds
21+ , TypeFamilies
22+ , TypeOperators
23+ , UndecidableInstances
24+#-}
25+
26+module Squeal.PostgreSQL.Expression.Aggregate
27+ ( Aggregate (..)
28+ , Distinction (..)
29+ , PGSum
30+ , PGAvg
31+ ) where
32+
33+import Control.DeepSeq
34+import Data.ByteString (ByteString)
35+import Data.Kind
36+import GHC.TypeLits
37+
38+import qualified GHC.Generics as GHC
39+import qualified Generics.SOP as SOP
40+
41+import Squeal.PostgreSQL.Alias
42+import Squeal.PostgreSQL.Expression
43+import Squeal.PostgreSQL.List
44+import Squeal.PostgreSQL.Render
45+import Squeal.PostgreSQL.Schema
46+
47+-- $setup
48+-- >>> import Squeal.PostgreSQL
49+
50+{- |
51+`Aggregate` functions compute a single result from a set of input values.
52+`Aggregate` functions can be used as `GroupedBy` `Expression`s as well
53+as `Squeal.PostgreSQL.Expression.Window.WindowFunction`s.
54+-}
55+class Aggregate expr1 exprN aggr
56+ | aggr -> expr1, aggr -> exprN where
57+
58+ -- | A special aggregation that does not require an input
59+ --
60+ -- >>> :{
61+ -- let
62+ -- expression :: Expression '[] commons ('Grouped bys) schemas params from ('NotNull 'PGint8)
63+ -- expression = countStar
64+ -- in printSQL expression
65+ -- :}
66+ -- count(*)
67+ countStar :: aggr ('NotNull 'PGint8)
68+
69+ -- | >>> :{
70+ -- let
71+ -- expression :: Expression '[] commons ('Grouped bys) schemas params '[tab ::: '["col" ::: null ty]] ('NotNull 'PGint8)
72+ -- expression = count (All #col)
73+ -- in printSQL expression
74+ -- :}
75+ -- count(ALL "col")
76+ count
77+ :: expr1 ty
78+ -- ^ what to count
79+ -> aggr ('NotNull 'PGint8)
80+
81+ -- | >>> :{
82+ -- let
83+ -- expression :: Expression '[] commons ('Grouped bys) schemas params '[tab ::: '["col" ::: 'Null 'PGnumeric]] ('Null 'PGnumeric)
84+ -- expression = sum_ (Distinct #col)
85+ -- in printSQL expression
86+ -- :}
87+ -- sum(DISTINCT "col")
88+ sum_
89+ :: expr1 (null ty)
90+ -> aggr ('Null (PGSum ty))
91+
92+ -- | input values, including nulls, concatenated into an array
93+ arrayAgg
94+ :: expr1 ty
95+ -> aggr ('Null ('PGvararray ty))
96+
97+ -- | aggregates values as a JSON array
98+ jsonAgg
99+ :: expr1 ty
100+ -> aggr ('Null 'PGjson)
101+
102+ -- | aggregates values as a JSON array
103+ jsonbAgg
104+ :: expr1 ty
105+ -> aggr ('Null 'PGjsonb)
106+
107+ {- |
108+ the bitwise AND of all non-null input values, or null if none
109+
110+ >>> :{
111+ let
112+ expression :: Expression '[] commons ('Grouped bys) schemas params '[tab ::: '["col" ::: null 'PGint4]] ('Null 'PGint4)
113+ expression = bitAnd (Distinct #col)
114+ in printSQL expression
115+ :}
116+ bit_and(DISTINCT "col")
117+ -}
118+ bitAnd
119+ :: int `In` PGIntegral
120+ => expr1 (null int)
121+ -- ^ what to aggregate
122+ -> aggr ('Null int)
123+
124+ {- |
125+ the bitwise OR of all non-null input values, or null if none
126+
127+ >>> :{
128+ let
129+ expression :: Expression '[] commons ('Grouped bys) schemas params '[tab ::: '["col" ::: null 'PGint4]] ('Null 'PGint4)
130+ expression = bitOr (All #col)
131+ in printSQL expression
132+ :}
133+ bit_or(ALL "col")
134+ -}
135+ bitOr
136+ :: int `In` PGIntegral
137+ => expr1 (null int)
138+ -- ^ what to aggregate
139+ -> aggr ('Null int)
140+
141+ {- |
142+ true if all input values are true, otherwise false
143+
144+ >>> :{
145+ let
146+ winFun :: WindowFunction '[] commons 'Ungrouped schemas params '[tab ::: '["col" ::: null 'PGbool]] ('Null 'PGbool)
147+ winFun = boolAnd #col
148+ in printSQL winFun
149+ :}
150+ bool_and("col")
151+ -}
152+ boolAnd
153+ :: expr1 (null 'PGbool)
154+ -- ^ what to aggregate
155+ -> aggr ('Null 'PGbool)
156+
157+ {- |
158+ true if at least one input value is true, otherwise false
159+
160+ >>> :{
161+ let
162+ expression :: Expression '[] commons ('Grouped bys) schemas params '[tab ::: '["col" ::: null 'PGbool]] ('Null 'PGbool)
163+ expression = boolOr (All #col)
164+ in printSQL expression
165+ :}
166+ bool_or(ALL "col")
167+ -}
168+ boolOr
169+ :: expr1 (null 'PGbool)
170+ -- ^ what to aggregate
171+ -> aggr ('Null 'PGbool)
172+
173+ {- |
174+ equivalent to `boolAnd`
175+
176+ >>> :{
177+ let
178+ expression :: Expression '[] commons ('Grouped bys) schemas params '[tab ::: '["col" ::: null 'PGbool]] ('Null 'PGbool)
179+ expression = every (Distinct #col)
180+ in printSQL expression
181+ :}
182+ every(DISTINCT "col")
183+ -}
184+ every
185+ :: expr1 (null 'PGbool)
186+ -- ^ what to aggregate
187+ -> aggr ('Null 'PGbool)
188+
189+ {- |maximum value of expression across all input values-}
190+ max_
191+ :: expr1 (null ty)
192+ -- ^ what to maximize
193+ -> aggr ('Null ty)
194+
195+ -- | minimum value of expression across all input values
196+ min_
197+ :: expr1 (null ty)
198+ -- ^ what to minimize
199+ -> aggr ('Null ty)
200+
201+ -- | the average (arithmetic mean) of all input values
202+ avg
203+ :: expr1 (null ty)
204+ -- ^ what to average
205+ -> aggr ('Null (PGAvg ty))
206+
207+ {- | correlation coefficient
208+
209+ >>> :{
210+ let
211+ expression :: Expression '[] c ('Grouped g) s p '[t ::: '["x" ::: 'NotNull 'PGfloat8, "y" ::: 'NotNull 'PGfloat8]] ('Null 'PGfloat8)
212+ expression = corr (All (#y *: #x))
213+ in printSQL expression
214+ :}
215+ corr(ALL "y", "x")
216+ -}
217+ corr
218+ :: exprN '[null 'PGfloat8, null 'PGfloat8]
219+ -> aggr ('Null 'PGfloat8)
220+
221+ {- | population covariance
222+
223+ >>> :{
224+ let
225+ expression :: Expression '[] c ('Grouped g) s p '[t ::: '["x" ::: 'NotNull 'PGfloat8, "y" ::: 'NotNull 'PGfloat8]] ('Null 'PGfloat8)
226+ expression = covarPop (All (#y *: #x))
227+ in printSQL expression
228+ :}
229+ covar_pop(ALL "y", "x")
230+ -}
231+ covarPop
232+ :: exprN '[null 'PGfloat8, null 'PGfloat8]
233+ -> aggr ('Null 'PGfloat8)
234+
235+ {- | sample covariance
236+
237+ >>> :{
238+ let
239+ winFun :: WindowFunction '[] c 'Ungrouped s p '[t ::: '["x" ::: 'NotNull 'PGfloat8, "y" ::: 'NotNull 'PGfloat8]] ('Null 'PGfloat8)
240+ winFun = covarSamp (#y *: #x)
241+ in printSQL winFun
242+ :}
243+ covar_samp("y", "x")
244+ -}
245+ covarSamp
246+ :: exprN '[null 'PGfloat8, null 'PGfloat8]
247+ -> aggr ('Null 'PGfloat8)
248+
249+ {- | average of the independent variable (sum(X)/N)
250+
251+ >>> :{
252+ let
253+ expression :: Expression '[] c ('Grouped g) s p '[t ::: '["x" ::: 'NotNull 'PGfloat8, "y" ::: 'NotNull 'PGfloat8]] ('Null 'PGfloat8)
254+ expression = regrAvgX (All (#y *: #x))
255+ in printSQL expression
256+ :}
257+ regr_avgx(ALL "y", "x")
258+ -}
259+ regrAvgX
260+ :: exprN '[null 'PGfloat8, null 'PGfloat8]
261+ -> aggr ('Null 'PGfloat8)
262+
263+ {- | average of the dependent variable (sum(Y)/N)
264+
265+ >>> :{
266+ let
267+ winFun :: WindowFunction '[] c 'Ungrouped s p '[t ::: '["x" ::: 'NotNull 'PGfloat8, "y" ::: 'NotNull 'PGfloat8]] ('Null 'PGfloat8)
268+ winFun = regrAvgY (#y *: #x)
269+ in printSQL winFun
270+ :}
271+ regr_avgy("y", "x")
272+ -}
273+ regrAvgY
274+ :: exprN '[null 'PGfloat8, null 'PGfloat8]
275+ -> aggr ('Null 'PGfloat8)
276+
277+ {- | number of input rows in which both expressions are nonnull
278+
279+ >>> :{
280+ let
281+ winFun :: WindowFunction '[] c 'Ungrouped s p '[t ::: '["x" ::: 'NotNull 'PGfloat8, "y" ::: 'NotNull 'PGfloat8]] ('Null 'PGint8)
282+ winFun = regrCount (#y *: #x)
283+ in printSQL winFun
284+ :}
285+ regr_count("y", "x")
286+ -}
287+ regrCount
288+ :: exprN '[null 'PGfloat8, null 'PGfloat8]
289+ -> aggr ('Null 'PGint8)
290+
291+ {- | y-intercept of the least-squares-fit linear equation determined by the (X, Y) pairs
292+ >>> :{
293+ let
294+ expression :: Expression '[] c ('Grouped g) s p '[t ::: '["x" ::: 'NotNull 'PGfloat8, "y" ::: 'NotNull 'PGfloat8]] ('Null 'PGfloat8)
295+ expression = regrIntercept (All (#y *: #x))
296+ in printSQL expression
297+ :}
298+ regr_intercept(ALL "y", "x")
299+ -}
300+ regrIntercept
301+ :: exprN '[null 'PGfloat8, null 'PGfloat8]
302+ -> aggr ('Null 'PGfloat8)
303+
304+ -- | @regr_r2(Y, X)@, square of the correlation coefficient
305+ regrR2
306+ :: exprN '[null 'PGfloat8, null 'PGfloat8]
307+ -> aggr ('Null 'PGfloat8)
308+
309+ -- | @regr_slope(Y, X)@, slope of the least-squares-fit linear equation
310+ -- determined by the (X, Y) pairs
311+ regrSlope
312+ :: exprN '[null 'PGfloat8, null 'PGfloat8]
313+ -> aggr ('Null 'PGfloat8)
314+
315+ -- | @regr_sxx(Y, X)@, sum(X^2) - sum(X)^2/N
316+ -- (“sum of squares” of the independent variable)
317+ regrSxx
318+ :: exprN '[null 'PGfloat8, null 'PGfloat8]
319+ -> aggr ('Null 'PGfloat8)
320+
321+ -- | @regr_sxy(Y, X)@, sum(X*Y) - sum(X) * sum(Y)/N
322+ -- (“sum of products” of independent times dependent variable)
323+ regrSxy
324+ :: exprN '[null 'PGfloat8, null 'PGfloat8]
325+ -> aggr ('Null 'PGfloat8)
326+
327+ -- | @regr_syy(Y, X)@, sum(Y^2) - sum(Y)^2/N
328+ -- (“sum of squares” of the dependent variable)
329+ regrSyy
330+ :: exprN '[null 'PGfloat8, null 'PGfloat8]
331+ -> aggr ('Null 'PGfloat8)
332+
333+ -- | historical alias for `stddevSamp`
334+ stddev
335+ :: expr1 (null ty)
336+ -> aggr ('Null (PGAvg ty))
337+
338+ -- | population standard deviation of the input values
339+ stddevPop
340+ :: expr1 (null ty)
341+ -> aggr ('Null (PGAvg ty))
342+
343+ -- | sample standard deviation of the input values
344+ stddevSamp
345+ :: expr1 (null ty)
346+ -> aggr ('Null (PGAvg ty))
347+
348+ -- | historical alias for `varSamp`
349+ variance
350+ :: expr1 (null ty)
351+ -> aggr ('Null (PGAvg ty))
352+
353+ -- | population variance of the input values
354+ -- (square of the population standard deviation)
355+ varPop
356+ :: expr1 (null ty)
357+ -> aggr ('Null (PGAvg ty))
358+
359+ -- | sample variance of the input values
360+ -- (square of the sample standard deviation)
361+ varSamp
362+ :: expr1 (null ty)
363+ -> aggr ('Null (PGAvg ty))
364+
365+{- |
366+`Distinction`s are used for the input of `Aggregate` `Expression`s.
367+`All` invokes the aggregate once for each input row.
368+`Distinct` invokes the aggregate once for each distinct value of the expression
369+(or distinct set of values, for multiple expressions) found in the input
370+-}
371+data Distinction (expr :: kind -> Type) (ty :: kind)
372+ = All (expr ty)
373+ | Distinct (expr ty)
374+ deriving (GHC.Generic,Show,Eq,Ord)
375+instance NFData (Distinction (Expression outer commons grp schemas params from) ty)
376+instance RenderSQL (Distinction (Expression outer commons grp schemas params from) ty) where
377+ renderSQL = \case
378+ All x -> "ALL" <+> renderSQL x
379+ Distinct x -> "DISTINCT" <+> renderSQL x
380+instance SOP.SListI tys => RenderSQL
381+ (Distinction (NP (Expression outer commons grp schemas params from)) tys) where
382+ renderSQL = \case
383+ All xs -> "ALL" <+> renderCommaSeparated renderSQL xs
384+ Distinct xs -> "DISTINCT" <+> renderCommaSeparated renderSQL xs
385+
386+instance Aggregate
387+ (Distinction (Expression outer commons 'Ungrouped schemas params from))
388+ (Distinction (NP (Expression outer commons 'Ungrouped schemas params from)))
389+ (Expression outer commons ('Grouped bys) schemas params from) where
390+ countStar = UnsafeExpression "count(*)"
391+ count = unsafeAggregate1 "count"
392+ sum_ = unsafeAggregate1 "sum"
393+ arrayAgg = unsafeAggregate1 "array_agg"
394+ jsonAgg = unsafeAggregate1 "json_agg"
395+ jsonbAgg = unsafeAggregate1 "jsonb_agg"
396+ bitAnd = unsafeAggregate1 "bit_and"
397+ bitOr = unsafeAggregate1 "bit_or"
398+ boolAnd = unsafeAggregate1 "bool_and"
399+ boolOr = unsafeAggregate1 "bool_or"
400+ every = unsafeAggregate1 "every"
401+ max_ = unsafeAggregate1 "max"
402+ min_ = unsafeAggregate1 "min"
403+ avg = unsafeAggregate1 "avg"
404+ corr = unsafeAggregateN "corr"
405+ covarPop = unsafeAggregateN "covar_pop"
406+ covarSamp = unsafeAggregateN "covar_samp"
407+ regrAvgX = unsafeAggregateN "regr_avgx"
408+ regrAvgY = unsafeAggregateN "regr_avgy"
409+ regrCount = unsafeAggregateN "regr_count"
410+ regrIntercept = unsafeAggregateN "regr_intercept"
411+ regrR2 = unsafeAggregateN "regr_r2"
412+ regrSlope = unsafeAggregateN "regr_slope"
413+ regrSxx = unsafeAggregateN "regr_sxx"
414+ regrSxy = unsafeAggregateN "regr_sxy"
415+ regrSyy = unsafeAggregateN "regr_syy"
416+ stddev = unsafeAggregate1 "stddev"
417+ stddevPop = unsafeAggregate1 "stddev_pop"
418+ stddevSamp = unsafeAggregate1 "stddev_samp"
419+ variance = unsafeAggregate1 "variance"
420+ varPop = unsafeAggregate1 "var_pop"
421+ varSamp = unsafeAggregate1 "var_samp"
422+
423+-- | escape hatch to define aggregate functions
424+unsafeAggregate1
425+ :: ByteString -- ^ aggregate function
426+ -> Distinction (Expression outer commons 'Ungrouped schemas params from) x
427+ -> Expression outer commons ('Grouped bys) schemas params from y
428+unsafeAggregate1 fun x = UnsafeExpression $ fun <> parenthesized (renderSQL x)
429+
430+unsafeAggregateN
431+ :: SOP.SListI xs
432+ => ByteString -- ^ function
433+ -> Distinction (NP (Expression outer commons 'Ungrouped schemas params from)) xs
434+ -> Expression outer commons ('Grouped bys) schemas params from y
435+unsafeAggregateN fun xs = UnsafeExpression $ fun <> parenthesized (renderSQL xs)
436+
437+-- | A type family that calculates `PGSum``PGType` of
438+-- a given argument `PGType`.
439+type family PGSum ty where
440+ PGSum 'PGint2 = 'PGint8
441+ PGSum 'PGint4 = 'PGint8
442+ PGSum 'PGint8 = 'PGnumeric
443+ PGSum 'PGfloat4 = 'PGfloat4
444+ PGSum 'PGfloat8 = 'PGfloat8
445+ PGSum 'PGnumeric = 'PGnumeric
446+ PGSum 'PGinterval = 'PGinterval
447+ PGSum 'PGmoney = 'PGmoney
448+ PGSum pg = TypeError
449+ ( 'Text "Squeal type error: Cannot sum with argument type "
450+ ':<>: 'ShowType pg )
451+
452+-- | A type family that calculates `PGAvg` type of a `PGType`.
453+type family PGAvg ty where
454+ PGAvg 'PGint2 = 'PGnumeric
455+ PGAvg 'PGint4 = 'PGnumeric
456+ PGAvg 'PGint8 = 'PGnumeric
457+ PGAvg 'PGnumeric = 'PGnumeric
458+ PGAvg 'PGfloat4 = 'PGfloat8
459+ PGAvg 'PGfloat8 = 'PGfloat8
460+ PGAvg 'PGinterval = 'PGinterval
461+ PGAvg pg = TypeError
462+ ('Text "Squeal type error: No average for " ':<>: 'ShowType pg)
squeal-postgresql/src/Squeal/PostgreSQL/Expression/Collection.hsnew file+169
@@ -0,0 +1,169 @@
1+{-|
2+Module: Squeal.PostgreSQL.Expression.Collection
3+Description: Array and composite functions
4+Copyright: (c) Eitan Chatav, 2019
5+Maintainer: eitan@morphism.tech
6+Stability: experimental
7+
8+Array and composite functions
9+-}
10+
11+{-# LANGUAGE
12+ AllowAmbiguousTypes
13+ , DataKinds
14+ , FlexibleContexts
15+ , FlexibleInstances
16+ , MultiParamTypeClasses
17+ , OverloadedLabels
18+ , OverloadedStrings
19+ , RankNTypes
20+ , ScopedTypeVariables
21+ , TypeApplications
22+ , TypeFamilies
23+ , TypeOperators
24+ , UndecidableInstances
25+#-}
26+
27+module Squeal.PostgreSQL.Expression.Collection
28+ ( array
29+ , array1
30+ , array2
31+ , cardinality
32+ , index
33+ , unnest
34+ , row
35+ , field
36+ ) where
37+
38+import Data.String
39+import Data.Word (Word64)
40+
41+import qualified Generics.SOP as SOP
42+
43+import Squeal.PostgreSQL.Alias
44+import Squeal.PostgreSQL.Expression
45+import Squeal.PostgreSQL.Expression.Set
46+import Squeal.PostgreSQL.List
47+import Squeal.PostgreSQL.Render
48+import Squeal.PostgreSQL.Schema
49+
50+-- $setup
51+-- >>> import Squeal.PostgreSQL
52+
53+-- | >>> printSQL $ array [null_, false, true]
54+-- ARRAY[NULL, FALSE, TRUE]
55+array
56+ :: [Expression outer commons grp schemas params from ty]
57+ -- ^ array elements
58+ -> Expression outer commons grp schemas params from (null ('PGvararray ty))
59+array xs = UnsafeExpression $ "ARRAY" <>
60+ bracketed (commaSeparated (renderSQL <$> xs))
61+
62+{- | construct a 1-dimensional fixed length array
63+
64+>>> printSQL $ array1 (null_ :* false *: true)
65+ARRAY[NULL, FALSE, TRUE]
66+
67+>>> :type array1 (null_ :* false *: true)
68+array1 (null_ :* false *: true)
69+ :: Expression
70+ outer
71+ commons
72+ grp
73+ schemas
74+ params
75+ from
76+ (null ('PGfixarray '[3] ('Null 'PGbool)))
77+-}
78+array1
79+ :: (n ~ Length tys, SOP.All ((~) ty) tys)
80+ => NP (Expression outer commons grp schemas params from) tys
81+ -> Expression outer commons grp schemas params from (null ('PGfixarray '[n] ty))
82+array1 xs = UnsafeExpression $ "ARRAY" <>
83+ bracketed (renderCommaSeparated renderSQL xs)
84+
85+{- | construct a 2-dimensional fixed length array
86+
87+>>> printSQL $ array2 ((null_ :* false *: true) *: (false :* null_ *: true))
88+ARRAY[[NULL, FALSE, TRUE], [FALSE, NULL, TRUE]]
89+
90+>>> :type array2 ((null_ :* false *: true) *: (false :* null_ *: true))
91+array2 ((null_ :* false *: true) *: (false :* null_ *: true))
92+ :: Expression
93+ outer
94+ commons
95+ grp
96+ schemas
97+ params
98+ from
99+ (null ('PGfixarray '[2, 3] ('Null 'PGbool)))
100+-}
101+array2
102+ :: ( SOP.All ((~) tys) tyss
103+ , SOP.All SOP.SListI tyss
104+ , Length tyss ~ n1
105+ , SOP.All ((~) ty) tys
106+ , Length tys ~ n2 )
107+ => NP (NP (Expression outer commons grp schemas params from)) tyss
108+ -> Expression outer commons grp schemas params from (null ('PGfixarray '[n1,n2] ty))
109+array2 xss = UnsafeExpression $ "ARRAY" <>
110+ bracketed (renderCommaSeparatedConstraint @SOP.SListI (bracketed . renderCommaSeparated renderSQL) xss)
111+
112+-- | >>> printSQL $ cardinality (array [null_, false, true])
113+-- cardinality(ARRAY[NULL, FALSE, TRUE])
114+cardinality :: null ('PGvararray ty) --> null 'PGint8
115+cardinality = unsafeFunction "cardinality"
116+
117+-- | >>> printSQL $ array [null_, false, true] & index 2
118+-- (ARRAY[NULL, FALSE, TRUE])[2]
119+index
120+ :: Word64 -- ^ index
121+ -> null ('PGvararray ty) --> NullifyType ty
122+index n expr = UnsafeExpression $
123+ parenthesized (renderSQL expr) <> "[" <> fromString (show n) <> "]"
124+
125+-- | Expand an array to a set of rows
126+unnest :: SetFunction "unnest" (null ('PGvararray ty)) '["unnest" ::: ty]
127+unnest = unsafeSetFunction
128+
129+-- | A row constructor is an expression that builds a row value
130+-- (also called a composite value) using values for its member fields.
131+--
132+-- >>> :{
133+-- type Complex = 'PGcomposite
134+-- '[ "real" ::: 'NotNull 'PGfloat8
135+-- , "imaginary" ::: 'NotNull 'PGfloat8 ]
136+-- :}
137+--
138+-- >>> let i = row (0 `as` #real :* 1 `as` #imaginary) :: Expression outer commons grp schemas params from ('NotNull Complex)
139+-- >>> printSQL i
140+-- ROW(0, 1)
141+row
142+ :: SOP.SListI row
143+ => NP (Aliased (Expression outer commons grp schemas params from)) row
144+ -- ^ zero or more expressions for the row field values
145+ -> Expression outer commons grp schemas params from (null ('PGcomposite row))
146+row exprs = UnsafeExpression $ "ROW" <> parenthesized
147+ (renderCommaSeparated (\ (expr `As` _) -> renderSQL expr) exprs)
148+
149+-- | >>> :{
150+-- type Complex = 'PGcomposite
151+-- '[ "real" ::: 'NotNull 'PGfloat8
152+-- , "imaginary" ::: 'NotNull 'PGfloat8 ]
153+-- type Schema = '["complex" ::: 'Typedef Complex]
154+-- :}
155+--
156+-- >>> let i = row (0 `as` #real :* 1 `as` #imaginary) :: Expression outer '[] grp (Public Schema) from params ('NotNull Complex)
157+-- >>> printSQL $ i & field #complex #imaginary
158+-- (ROW(0, 1)::"complex")."imaginary"
159+field
160+ :: ( Has sch schemas schema
161+ , Has tydef schema ('Typedef ('PGcomposite row))
162+ , Has field row ty)
163+ => QualifiedAlias sch tydef -- ^ row type
164+ -> Alias field -- ^ field name
165+ -> Expression outer commons grp schemas params from ('NotNull ('PGcomposite row))
166+ -> Expression outer commons grp schemas params from ty
167+field td fld expr = UnsafeExpression $
168+ parenthesized (renderSQL expr <> "::" <> renderSQL td)
169+ <> "." <> renderSQL fld
squeal-postgresql/src/Squeal/PostgreSQL/Expression/Comparison.hsnew file+206
@@ -0,0 +1,206 @@
1+{-|
2+Module: Squeal.PostgreSQL.Expression.Comparison
3+Description: Comparison expressions
4+Copyright: (c) Eitan Chatav, 2019
5+Maintainer: eitan@morphism.tech
6+Stability: experimental
7+
8+Comparison functions and operators
9+-}
10+
11+{-# LANGUAGE
12+ OverloadedStrings
13+ , RankNTypes
14+ , TypeInType
15+ , TypeOperators
16+#-}
17+
18+module Squeal.PostgreSQL.Expression.Comparison
19+ ( (.==)
20+ , (./=)
21+ , (.>=)
22+ , (.<)
23+ , (.<=)
24+ , (.>)
25+ , greatest
26+ , least
27+ , BetweenExpr
28+ , between
29+ , notBetween
30+ , betweenSymmetric
31+ , notBetweenSymmetric
32+ , isDistinctFrom
33+ , isNotDistinctFrom
34+ , isTrue
35+ , isNotTrue
36+ , isFalse
37+ , isNotFalse
38+ , isUnknown
39+ , isNotUnknown
40+ ) where
41+
42+import Data.ByteString
43+
44+import Squeal.PostgreSQL.Expression
45+import Squeal.PostgreSQL.Expression.Logic
46+import Squeal.PostgreSQL.Render
47+import Squeal.PostgreSQL.Schema
48+
49+-- $setup
50+-- >>> import Squeal.PostgreSQL
51+
52+-- | Comparison operations like `.==`, `./=`, `.>`, `.>=`, `.<` and `.<=`
53+-- will produce @NULL@s if one of their arguments is @NULL@.
54+--
55+-- >>> printSQL $ true .== null_
56+-- (TRUE = NULL)
57+(.==) :: Operator (null0 ty) (null1 ty) ('Null 'PGbool)
58+(.==) = unsafeBinaryOp "="
59+infix 4 .==
60+
61+-- | >>> printSQL $ true ./= null_
62+-- (TRUE <> NULL)
63+(./=) :: Operator (null0 ty) (null1 ty) ('Null 'PGbool)
64+(./=) = unsafeBinaryOp "<>"
65+infix 4 ./=
66+
67+-- | >>> printSQL $ true .>= null_
68+-- (TRUE >= NULL)
69+(.>=) :: Operator (null0 ty) (null1 ty) ('Null 'PGbool)
70+(.>=) = unsafeBinaryOp ">="
71+infix 4 .>=
72+
73+-- | >>> printSQL $ true .< null_
74+-- (TRUE < NULL)
75+(.<) :: Operator (null0 ty) (null1 ty) ('Null 'PGbool)
76+(.<) = unsafeBinaryOp "<"
77+infix 4 .<
78+
79+-- | >>> printSQL $ true .<= null_
80+-- (TRUE <= NULL)
81+(.<=) :: Operator (null0 ty) (null1 ty) ('Null 'PGbool)
82+(.<=) = unsafeBinaryOp "<="
83+infix 4 .<=
84+
85+-- | >>> printSQL $ true .> null_
86+-- (TRUE > NULL)
87+(.>) :: Operator (null0 ty) (null1 ty) ('Null 'PGbool)
88+(.>) = unsafeBinaryOp ">"
89+infix 4 .>
90+
91+-- | >>> let expr = greatest [param @1] currentTimestamp :: Expression outer commons grp schemas '[ 'NotNull 'PGtimestamptz] from ('NotNull 'PGtimestamptz)
92+-- >>> printSQL expr
93+-- GREATEST(($1 :: timestamp with time zone), CURRENT_TIMESTAMP)
94+greatest :: FunctionVar ty ty ty
95+greatest = unsafeFunctionVar "GREATEST"
96+
97+-- | >>> printSQL $ least [null_] currentTimestamp
98+-- LEAST(NULL, CURRENT_TIMESTAMP)
99+least :: FunctionVar ty ty ty
100+least = unsafeFunctionVar "LEAST"
101+
102+{- |
103+A @RankNType@ for comparison expressions like `between`.
104+-}
105+type BetweenExpr
106+ = forall outer commons grp schemas params from ty
107+ . Expression outer commons grp schemas params from ty
108+ -> ( Expression outer commons grp schemas params from ty
109+ , Expression outer commons grp schemas params from ty ) -- ^ bounds
110+ -> Condition outer commons grp schemas params from
111+
112+unsafeBetweenExpr :: ByteString -> BetweenExpr
113+unsafeBetweenExpr fun a (x,y) = UnsafeExpression $
114+ renderSQL a <+> fun <+> renderSQL x <+> "AND" <+> renderSQL y
115+
116+{- | >>> printSQL $ true `between` (null_, false)
117+TRUE BETWEEN NULL AND FALSE
118+-}
119+between :: BetweenExpr
120+between = unsafeBetweenExpr "BETWEEN"
121+
122+{- | >>> printSQL $ true `notBetween` (null_, false)
123+TRUE NOT BETWEEN NULL AND FALSE
124+-}
125+notBetween :: BetweenExpr
126+notBetween = unsafeBetweenExpr "NOT BETWEEN"
127+
128+{- | between, after sorting the comparison values
129+
130+>>> printSQL $ true `betweenSymmetric` (null_, false)
131+TRUE BETWEEN SYMMETRIC NULL AND FALSE
132+-}
133+betweenSymmetric :: BetweenExpr
134+betweenSymmetric = unsafeBetweenExpr "BETWEEN SYMMETRIC"
135+
136+{- | not between, after sorting the comparison values
137+
138+>>> printSQL $ true `notBetweenSymmetric` (null_, false)
139+TRUE NOT BETWEEN SYMMETRIC NULL AND FALSE
140+-}
141+notBetweenSymmetric :: BetweenExpr
142+notBetweenSymmetric = unsafeBetweenExpr "NOT BETWEEN SYMMETRIC"
143+
144+{- | not equal, treating null like an ordinary value
145+
146+>>> printSQL $ true `isDistinctFrom` null_
147+(TRUE IS DISTINCT FROM NULL)
148+-}
149+isDistinctFrom :: Operator (null0 ty) (null1 ty) ('Null 'PGbool)
150+isDistinctFrom = unsafeBinaryOp "IS DISTINCT FROM"
151+
152+{- | equal, treating null like an ordinary value
153+
154+>>> printSQL $ true `isNotDistinctFrom` null_
155+(TRUE IS NOT DISTINCT FROM NULL)
156+-}
157+isNotDistinctFrom :: Operator (null0 ty) (null1 ty) ('NotNull 'PGbool)
158+isNotDistinctFrom = unsafeBinaryOp "IS NOT DISTINCT FROM"
159+
160+{- | is true
161+
162+>>> printSQL $ true & isTrue
163+(TRUE IS TRUE)
164+-}
165+isTrue :: null0 'PGbool --> null1 'PGbool
166+isTrue = unsafeRightOp "IS TRUE"
167+
168+{- | is false or unknown
169+
170+>>> printSQL $ true & isNotTrue
171+(TRUE IS NOT TRUE)
172+-}
173+isNotTrue :: null0 'PGbool --> null1 'PGbool
174+isNotTrue = unsafeRightOp "IS NOT TRUE"
175+
176+{- | is false
177+
178+>>> printSQL $ true & isFalse
179+(TRUE IS FALSE)
180+-}
181+isFalse :: null0 'PGbool --> null1 'PGbool
182+isFalse = unsafeRightOp "IS FALSE"
183+
184+{- | is true or unknown
185+
186+>>> printSQL $ true & isNotFalse
187+(TRUE IS NOT FALSE)
188+-}
189+isNotFalse :: null0 'PGbool --> null1 'PGbool
190+isNotFalse = unsafeRightOp "IS NOT FALSE"
191+
192+{- | is unknown
193+
194+>>> printSQL $ true & isUnknown
195+(TRUE IS UNKNOWN)
196+-}
197+isUnknown :: null0 'PGbool --> null1 'PGbool
198+isUnknown = unsafeRightOp "IS UNKNOWN"
199+
200+{- | is true or false
201+
202+>>> printSQL $ true & isNotUnknown
203+(TRUE IS NOT UNKNOWN)
204+-}
205+isNotUnknown :: null0 'PGbool --> null1 'PGbool
206+isNotUnknown = unsafeRightOp "IS NOT UNKNOWN"
squeal-postgresql/src/Squeal/PostgreSQL/Expression/Json.hsnew file+462
@@ -0,0 +1,462 @@
1+{-|
2+Module: Squeal.PostgreSQL.Expression.Json
3+Description: Json and Jsonb functions and operators
4+Copyright: (c) Eitan Chatav, 2019
5+Maintainer: eitan@morphism.tech
6+Stability: experimental
7+
8+Json and Jsonb functions and operators
9+-}
10+
11+{-# LANGUAGE
12+ DataKinds
13+ , FlexibleContexts
14+ , FlexibleInstances
15+ , GADTs
16+ , OverloadedLabels
17+ , OverloadedStrings
18+ , PolyKinds
19+ , RankNTypes
20+ , ScopedTypeVariables
21+ , TypeApplications
22+ , TypeOperators
23+ , UndecidableInstances
24+ , UndecidableSuperClasses
25+#-}
26+
27+module Squeal.PostgreSQL.Expression.Json
28+ ( -- * Json and Jsonb operators
29+ (.->)
30+ , (.->>)
31+ , (.#>)
32+ , (.#>>)
33+ -- * Jsonb operators
34+ , (.?)
35+ , (.?|)
36+ , (.?&)
37+ , (.-.)
38+ , (#-.)
39+ -- * Json and Jsonb functions
40+ , toJson
41+ , toJsonb
42+ , arrayToJson
43+ , rowToJson
44+ , jsonBuildArray
45+ , jsonbBuildArray
46+ , JsonBuildObject (..)
47+ , jsonObject
48+ , jsonbObject
49+ , jsonZipObject
50+ , jsonbZipObject
51+ , jsonArrayLength
52+ , jsonbArrayLength
53+ , jsonTypeof
54+ , jsonbTypeof
55+ , jsonStripNulls
56+ , jsonbStripNulls
57+ , jsonbSet
58+ , jsonbInsert
59+ , jsonbPretty
60+ -- * Json and Jsonb set returning functions
61+ , jsonEach
62+ , jsonbEach
63+ , jsonEachText
64+ , jsonbEachText
65+ , jsonObjectKeys
66+ , jsonbObjectKeys
67+ , JsonPopulateFunction
68+ , jsonPopulateRecord
69+ , jsonbPopulateRecord
70+ , jsonPopulateRecordSet
71+ , jsonbPopulateRecordSet
72+ , JsonToRecordFunction
73+ , jsonToRecord
74+ , jsonbToRecord
75+ , jsonToRecordSet
76+ , jsonbToRecordSet
77+ ) where
78+
79+import Data.ByteString (ByteString)
80+import GHC.TypeLits
81+
82+import Squeal.PostgreSQL.Alias
83+import Squeal.PostgreSQL.Expression
84+import Squeal.PostgreSQL.Expression.Set
85+import Squeal.PostgreSQL.Expression.Type
86+import Squeal.PostgreSQL.List
87+import Squeal.PostgreSQL.Query
88+import Squeal.PostgreSQL.Render
89+import Squeal.PostgreSQL.Schema
90+
91+import qualified Generics.SOP as SOP
92+
93+-- $setup
94+-- >>> import Squeal.PostgreSQL
95+-- >>> import Data.Aeson
96+
97+{-----------------------------------------
98+ -- json and jsonb support
99+
100+See https://www.postgresql.org/docs/10/static/functions-json.html -- most
101+comments lifted directly from this page.
102+
103+Table 9.44: json and jsonb operators
104+-----------------------------------------}
105+
106+-- | Get JSON value (object field or array element) at a key.
107+(.->)
108+ :: (json `In` PGJsonType, key `In` PGJsonKey)
109+ => Operator (null json) (null key) ('Null json)
110+infixl 8 .->
111+(.->) = unsafeBinaryOp "->"
112+
113+-- | Get JSON value (object field or array element) at a key, as text.
114+(.->>)
115+ :: (json `In` PGJsonType, key `In` PGJsonKey)
116+ => Operator (null json) (null key) ('Null 'PGtext)
117+infixl 8 .->>
118+(.->>) = unsafeBinaryOp "->>"
119+
120+-- | Get JSON value at a specified path.
121+(.#>)
122+ :: json `In` PGJsonType
123+ => Operator (null json) (null ('PGvararray ('NotNull 'PGtext))) ('Null json)
124+infixl 8 .#>
125+(.#>) = unsafeBinaryOp "#>"
126+
127+-- | Get JSON value at a specified path as text.
128+(.#>>)
129+ :: json `In` PGJsonType
130+ => Operator (null json) (null ('PGvararray ('NotNull 'PGtext))) ('Null 'PGtext)
131+infixl 8 .#>>
132+(.#>>) = unsafeBinaryOp "#>>"
133+
134+-- Additional jsonb operators
135+
136+-- | Does the string exist as a top-level key within the JSON value?
137+(.?) :: Operator (null 'PGjsonb) (null 'PGtext) ('Null 'PGbool)
138+infixl 9 .?
139+(.?) = unsafeBinaryOp "?"
140+
141+-- | Do any of these array strings exist as top-level keys?
142+(.?|) :: Operator
143+ (null 'PGjsonb)
144+ (null ('PGvararray ('NotNull 'PGtext)))
145+ ('Null 'PGbool)
146+infixl 9 .?|
147+(.?|) = unsafeBinaryOp "?|"
148+
149+-- | Do all of these array strings exist as top-level keys?
150+(.?&) :: Operator
151+ (null 'PGjsonb)
152+ (null ('PGvararray ('NotNull 'PGtext)))
153+ ('Null 'PGbool)
154+infixl 9 .?&
155+(.?&) = unsafeBinaryOp "?&"
156+
157+-- | Delete a key or keys from a JSON object, or remove an array element.
158+--
159+-- If the right operand is
160+--
161+-- @ text @: Delete key / value pair or string element from left operand.
162+-- Key / value pairs are matched based on their key value,
163+--
164+-- @ text[] @: Delete multiple key / value pairs or string elements
165+-- from left operand. Key / value pairs are matched based on their key value,
166+--
167+-- @ integer @: Delete the array element with specified index (Negative integers
168+-- count from the end). Throws an error if top level container is not an array.
169+(.-.)
170+ :: key `In` '[ 'PGtext, 'PGvararray ('NotNull 'PGtext), 'PGint4, 'PGint2 ]
171+ => Operator (null 'PGjsonb) (null key) (null 'PGjsonb)
172+infixl 6 .-.
173+(.-.) = unsafeBinaryOp "-"
174+
175+-- | Delete the field or element with specified path (for JSON arrays, negative
176+-- integers count from the end)
177+(#-.) :: Operator (null 'PGjsonb) (null ('PGvararray ('NotNull 'PGtext))) (null 'PGjsonb)
178+infixl 6 #-.
179+(#-.) = unsafeBinaryOp "#-"
180+
181+{-----------------------------------------
182+Table 9.45: JSON creation functions
183+-----------------------------------------}
184+
185+-- | Returns the value as json. Arrays and composites are converted
186+-- (recursively) to arrays and objects; otherwise, if there is a cast from the
187+-- type to json, the cast function will be used to perform the conversion;
188+-- otherwise, a scalar value is produced. For any scalar type other than a
189+-- number, a Boolean, or a null value, the text representation will be used, in
190+-- such a fashion that it is a valid json value.
191+toJson :: null ty --> null 'PGjson
192+toJson = unsafeFunction "to_json"
193+
194+-- | Returns the value as jsonb. Arrays and composites are converted
195+-- (recursively) to arrays and objects; otherwise, if there is a cast from the
196+-- type to json, the cast function will be used to perform the conversion;
197+-- otherwise, a scalar value is produced. For any scalar type other than a
198+-- number, a Boolean, or a null value, the text representation will be used, in
199+-- such a fashion that it is a valid jsonb value.
200+toJsonb :: null ty --> null 'PGjsonb
201+toJsonb = unsafeFunction "to_jsonb"
202+
203+-- | Returns the array as a JSON array. A PostgreSQL multidimensional array
204+-- becomes a JSON array of arrays.
205+arrayToJson :: null ('PGvararray ty) --> null 'PGjson
206+arrayToJson = unsafeFunction "array_to_json"
207+
208+-- | Returns the row as a JSON object.
209+rowToJson :: null ('PGcomposite ty) --> null 'PGjson
210+rowToJson = unsafeFunction "row_to_json"
211+
212+-- | Builds a possibly-heterogeneously-typed JSON array out of a variadic
213+-- argument list.
214+jsonBuildArray :: SOP.SListI tuple => tuple ---> null 'PGjson
215+jsonBuildArray = unsafeFunctionN "json_build_array"
216+
217+-- | Builds a possibly-heterogeneously-typed (binary) JSON array out of a
218+-- variadic argument list.
219+jsonbBuildArray :: SOP.SListI tuple => tuple ---> null 'PGjsonb
220+jsonbBuildArray = unsafeFunctionN "jsonb_build_array"
221+
222+-- | Builds a possibly-heterogeneously-typed JSON object out of a variadic
223+-- argument list. The elements of the argument list must alternate between text
224+-- and values.
225+class SOP.SListI tys => JsonBuildObject tys where
226+
227+ jsonBuildObject :: tys ---> null 'PGjson
228+ jsonBuildObject = unsafeFunctionN "json_build_object"
229+
230+ jsonbBuildObject :: tys ---> null 'PGjsonb
231+ jsonbBuildObject = unsafeFunctionN "jsonb_build_object"
232+
233+instance JsonBuildObject '[]
234+instance (JsonBuildObject tys, key `In` PGJsonKey)
235+ => JsonBuildObject ('NotNull key ': value ': tys)
236+
237+-- | Builds a JSON object out of a text array.
238+-- The array must have two dimensions
239+-- such that each inner array has exactly two elements,
240+-- which are taken as a key/value pair.
241+jsonObject
242+ :: null ('PGfixarray '[n,2] ('NotNull 'PGtext))
243+ --> null 'PGjson
244+jsonObject = unsafeFunction "json_object"
245+
246+-- | Builds a binary JSON object out of a text array.
247+-- The array must have two dimensions
248+-- such that each inner array has exactly two elements,
249+-- which are taken as a key/value pair.
250+jsonbObject
251+ :: null ('PGfixarray '[n,2] ('NotNull 'PGtext))
252+ --> null 'PGjsonb
253+jsonbObject = unsafeFunction "jsonb_object"
254+
255+-- | This is an alternate form of 'jsonObject' that takes two arrays; one for
256+-- keys and one for values, that are zipped pairwise to create a JSON object.
257+jsonZipObject ::
258+ '[ null ('PGvararray ('NotNull 'PGtext))
259+ , null ('PGvararray ('NotNull 'PGtext)) ]
260+ ---> null 'PGjson
261+jsonZipObject = unsafeFunctionN "json_object"
262+
263+-- | This is an alternate form of 'jsonbObject' that takes two arrays; one for
264+-- keys and one for values, that are zipped pairwise to create a binary JSON
265+-- object.
266+jsonbZipObject ::
267+ '[ null ('PGvararray ('NotNull 'PGtext))
268+ , null ('PGvararray ('NotNull 'PGtext)) ]
269+ ---> null 'PGjsonb
270+jsonbZipObject = unsafeFunctionN "jsonb_object"
271+
272+{-----------------------------------------
273+Table 9.46: JSON processing functions
274+-----------------------------------------}
275+
276+-- | Returns the number of elements in the outermost JSON array.
277+jsonArrayLength :: null 'PGjson --> null 'PGint4
278+jsonArrayLength = unsafeFunction "json_array_length"
279+
280+-- | Returns the number of elements in the outermost binary JSON array.
281+jsonbArrayLength :: null 'PGjsonb --> null 'PGint4
282+jsonbArrayLength = unsafeFunction "jsonb_array_length"
283+
284+-- | Returns the type of the outermost JSON value as a text string. Possible
285+-- types are object, array, string, number, boolean, and null.
286+jsonTypeof :: null 'PGjson --> null 'PGtext
287+jsonTypeof = unsafeFunction "json_typeof"
288+
289+-- | Returns the type of the outermost binary JSON value as a text string.
290+-- Possible types are object, array, string, number, boolean, and null.
291+jsonbTypeof :: null 'PGjsonb --> null 'PGtext
292+jsonbTypeof = unsafeFunction "jsonb_typeof"
293+
294+-- | Returns its argument with all object fields that have null values omitted.
295+-- Other null values are untouched.
296+jsonStripNulls :: null 'PGjson --> null 'PGjson
297+jsonStripNulls = unsafeFunction "json_strip_nulls"
298+
299+-- | Returns its argument with all object fields that have null values omitted.
300+-- Other null values are untouched.
301+jsonbStripNulls :: null 'PGjsonb --> null 'PGjsonb
302+jsonbStripNulls = unsafeFunction "jsonb_strip_nulls"
303+
304+-- | @ jsonbSet target path new_value create_missing @
305+--
306+-- Returns target with the section designated by path replaced by @new_value@,
307+-- or with @new_value@ added if create_missing is
308+-- `Squeal.PostgreSQL.Expression.Logic.true` and the
309+-- item designated by path does not exist. As with the path orientated
310+-- operators, negative integers that appear in path count from the end of JSON
311+-- arrays.
312+jsonbSet ::
313+ '[ null 'PGjsonb, null ('PGvararray ('NotNull 'PGtext))
314+ , null 'PGjsonb, null 'PGbool ] ---> null 'PGjsonb
315+jsonbSet = unsafeFunctionN "jsonbSet"
316+
317+-- | @ jsonbInsert target path new_value insert_after @
318+--
319+-- Returns target with @new_value@ inserted. If target section designated by
320+-- path is in a JSONB array, @new_value@ will be inserted before target or after
321+-- if @insert_after@ is `Squeal.PostgreSQL.Expression.Logic.true`.
322+-- If target section designated by
323+-- path is in JSONB object, @new_value@ will be inserted only if target does not
324+-- exist. As with the path orientated operators, negative integers that appear
325+-- in path count from the end of JSON arrays.
326+jsonbInsert ::
327+ '[ null 'PGjsonb, null ('PGvararray ('NotNull 'PGtext))
328+ , null 'PGjsonb, null 'PGbool ] ---> null 'PGjsonb
329+jsonbInsert = unsafeFunctionN "jsonb_insert"
330+
331+-- | Returns its argument as indented JSON text.
332+jsonbPretty :: null 'PGjsonb --> null 'PGtext
333+jsonbPretty = unsafeFunction "jsonb_pretty"
334+
335+{- | Expands the outermost JSON object into a set of key/value pairs.
336+
337+>>> printSQL (select Star (from (jsonEach (literal (Json (object ["a" .= "foo", "b" .= "bar"]))))))
338+SELECT * FROM json_each(('{"a":"foo","b":"bar"}' :: json))
339+-}
340+jsonEach :: SetFunction "json_each" (null 'PGjson)
341+ '["key" ::: 'NotNull 'PGtext, "value" ::: 'NotNull 'PGjson]
342+jsonEach = unsafeSetFunction
343+
344+{- | Expands the outermost binary JSON object into a set of key/value pairs.
345+
346+>>> printSQL (select Star (from (jsonbEach (literal (Jsonb (object ["a" .= "foo", "b" .= "bar"]))))))
347+SELECT * FROM jsonb_each(('{"a":"foo","b":"bar"}' :: jsonb))
348+-}
349+jsonbEach
350+ :: SetFunction "jsonb_each" (nullity 'PGjsonb)
351+ '["key" ::: 'NotNull 'PGtext, "value" ::: 'NotNull 'PGjson]
352+jsonbEach = unsafeSetFunction
353+
354+{- | Expands the outermost JSON object into a set of key/value pairs.
355+
356+>>> printSQL (select Star (from (jsonEachText (literal (Json (object ["a" .= "foo", "b" .= "bar"]))))))
357+SELECT * FROM json_each_text(('{"a":"foo","b":"bar"}' :: json))
358+-}
359+jsonEachText
360+ :: SetFunction "json_each_text" (null 'PGjson)
361+ '["key" ::: 'NotNull 'PGtext, "value" ::: 'NotNull 'PGtext]
362+jsonEachText = unsafeSetFunction
363+
364+{- | Expands the outermost binary JSON object into a set of key/value pairs.
365+
366+>>> printSQL (select Star (from (jsonbEachText (literal (Jsonb (object ["a" .= "foo", "b" .= "bar"]))))))
367+SELECT * FROM jsonb_each_text(('{"a":"foo","b":"bar"}' :: jsonb))
368+-}
369+jsonbEachText
370+ :: SetFunction "jsonb_each_text" (null 'PGjsonb)
371+ '["key" ::: 'NotNull 'PGtext, "value" ::: 'NotNull 'PGtext]
372+jsonbEachText = unsafeSetFunction
373+
374+{- | Returns set of keys in the outermost JSON object.
375+
376+>>> printSQL (jsonObjectKeys (literal (Json (object ["a" .= "foo", "b" .= "bar"]))))
377+json_object_keys(('{"a":"foo","b":"bar"}' :: json))
378+-}
379+jsonObjectKeys
380+ :: SetFunction "json_object_keys" (nullity 'PGjson)
381+ '["json_object_keys" ::: 'NotNull 'PGtext]
382+jsonObjectKeys = unsafeSetFunction
383+
384+{- | Returns set of keys in the outermost JSON object.
385+
386+>>> printSQL (jsonbObjectKeys (literal (Jsonb (object ["a" .= "foo", "b" .= "bar"]))))
387+jsonb_object_keys(('{"a":"foo","b":"bar"}' :: jsonb))
388+-}
389+jsonbObjectKeys
390+ :: SetFunction "jsonb_object_keys" (null 'PGjsonb)
391+ '["jsonb_object_keys" ::: 'NotNull 'PGtext]
392+jsonbObjectKeys = unsafeSetFunction
393+
394+-- | Build rows from Json types.
395+type JsonPopulateFunction fun json
396+ = forall schemas row outer commons params
397+ . json `In` PGJsonType
398+ => TypeExpression schemas ('NotNull ('PGcomposite row)) -- ^ row type
399+ -> Expression outer commons 'Ungrouped schemas params '[] ('NotNull json)
400+ -- ^ json type
401+ -> FromClause outer commons schemas params '[fun ::: row]
402+
403+unsafePopulateFunction
404+ :: forall fun ty
405+ . KnownSymbol fun => Alias fun -> JsonPopulateFunction fun ty
406+unsafePopulateFunction _fun ty expr = UnsafeFromClause $ renderSymbol @fun
407+ <> parenthesized ("null::" <> renderSQL ty <> ", " <> renderSQL expr)
408+
409+-- | Expands the JSON expression to a row whose columns match the record
410+-- type defined by the given table.
411+jsonPopulateRecord :: JsonPopulateFunction "json_populate_record" 'PGjson
412+jsonPopulateRecord = unsafePopulateFunction #json_populate_record
413+
414+-- | Expands the binary JSON expression to a row whose columns match the record
415+-- type defined by the given table.
416+jsonbPopulateRecord :: JsonPopulateFunction "jsonb_populate_record" 'PGjsonb
417+jsonbPopulateRecord = unsafePopulateFunction #jsonb_populate_record
418+
419+-- | Expands the outermost array of objects in the given JSON expression to a
420+-- set of rows whose columns match the record type defined by the given table.
421+jsonPopulateRecordSet :: JsonPopulateFunction "json_populate_record_set" 'PGjson
422+jsonPopulateRecordSet = unsafePopulateFunction #json_populate_record_set
423+
424+-- | Expands the outermost array of objects in the given binary JSON expression
425+-- to a set of rows whose columns match the record type defined by the given
426+-- table.
427+jsonbPopulateRecordSet :: JsonPopulateFunction "jsonb_populate_record_set" 'PGjsonb
428+jsonbPopulateRecordSet = unsafePopulateFunction #jsonb_populate_record_set
429+
430+-- | Build rows from Json types.
431+type JsonToRecordFunction json
432+ = forall outer commons schemas params tab row
433+ . (SOP.SListI row, json `In` PGJsonType)
434+ => Expression outer commons 'Ungrouped schemas params '[] ('NotNull json)
435+ -- ^ json type
436+ -> Aliased (NP (Aliased (TypeExpression schemas))) (tab ::: row)
437+ -- ^ row type
438+ -> FromClause outer commons schemas params '[tab ::: row]
439+
440+unsafeRecordFunction :: ByteString -> JsonToRecordFunction json
441+unsafeRecordFunction fun expr (types `As` tab) = UnsafeFromClause $
442+ fun <> parenthesized (renderSQL expr) <+> "AS" <+> renderSQL tab
443+ <> parenthesized (renderCommaSeparated renderTy types)
444+ where
445+ renderTy :: Aliased (TypeExpression schemas) ty -> ByteString
446+ renderTy (ty `As` alias) = renderSQL alias <+> renderSQL ty
447+
448+-- | Builds an arbitrary record from a JSON object.
449+jsonToRecord :: JsonToRecordFunction 'PGjson
450+jsonToRecord = unsafeRecordFunction "json_to_record"
451+
452+-- | Builds an arbitrary record from a binary JSON object.
453+jsonbToRecord :: JsonToRecordFunction 'PGjsonb
454+jsonbToRecord = unsafeRecordFunction "jsonb_to_record"
455+
456+-- | Builds an arbitrary set of records from a JSON array of objects.
457+jsonToRecordSet :: JsonToRecordFunction 'PGjson
458+jsonToRecordSet = unsafeRecordFunction "json_to_record_set"
459+
460+-- | Builds an arbitrary set of records from a binary JSON array of objects.
461+jsonbToRecordSet :: JsonToRecordFunction 'PGjsonb
462+jsonbToRecordSet = unsafeRecordFunction "jsonb_to_record_set"
squeal-postgresql/src/Squeal/PostgreSQL/Expression/Literal.hsnew file+87
@@ -0,0 +1,87 @@
1+{-|
2+Module: Squeal.PostgreSQL.Expression.Literal
3+Description: Literal expressions
4+Copyright: (c) Eitan Chatav, 2019
5+Maintainer: eitan@morphism.tech
6+Stability: experimental
7+
8+Literal expressions
9+-}
10+
11+{-# LANGUAGE
12+ FlexibleContexts
13+ , FlexibleInstances
14+ , LambdaCase
15+ , OverloadedStrings
16+ , RankNTypes
17+ , ScopedTypeVariables
18+ , TypeApplications
19+ , TypeSynonymInstances
20+ , UndecidableInstances
21+#-}
22+
23+module Squeal.PostgreSQL.Expression.Literal (Literal (..)) where
24+
25+import ByteString.StrictBuilder (builderBytes)
26+import Data.ByteString.Lazy (toStrict)
27+import Data.Int
28+import Data.String
29+import Data.Text (Text)
30+
31+import qualified Data.Aeson as JSON
32+import qualified Data.Text as Text
33+import qualified Data.Text.Lazy as Lazy (Text)
34+import qualified Data.Text.Lazy as Lazy.Text
35+
36+import Squeal.PostgreSQL.Binary
37+import Squeal.PostgreSQL.Expression
38+import Squeal.PostgreSQL.Expression.Logic
39+import Squeal.PostgreSQL.PG
40+import Squeal.PostgreSQL.Render
41+
42+{- |
43+The `Literal` class allows embedding a Haskell value directly
44+as an `Expression` using `literal`.
45+
46+>>> printSQL (literal 'a')
47+E'a'
48+
49+>>> printSQL (literal (1 :: Double))
50+1.0
51+
52+>>> printSQL (literal (Json [1 :: Double, 2]))
53+('[1.0,2.0]' :: json)
54+
55+>>> printSQL (literal (Enumerated GT))
56+'GT'
57+-}
58+class Literal hask where literal :: hask -> Expr (null (PG hask))
59+instance Literal Bool where
60+ literal = \case
61+ True -> true
62+ False -> false
63+instance JSON.ToJSON hask => Literal (Json hask) where
64+ literal = UnsafeExpression . parenthesized . (<> " :: json")
65+ . singleQuotedUtf8 . toStrict . JSON.encode . getJson
66+instance JSON.ToJSON hask => Literal (Jsonb hask) where
67+ literal = UnsafeExpression . parenthesized . (<> " :: jsonb")
68+ . singleQuotedUtf8 . toStrict . JSON.encode . getJsonb
69+instance Literal Char where
70+ literal chr = UnsafeExpression $
71+ "E\'" <> fromString (escape chr) <> "\'"
72+instance Literal String where literal = fromString
73+instance Literal Int16 where literal = fromIntegral
74+instance Literal Int32 where literal = fromIntegral
75+instance Literal Int64 where literal = fromIntegral
76+instance Literal Float where literal = fromRational . toRational
77+instance Literal Double where literal = fromRational . toRational
78+instance Literal Text where literal = fromString . Text.unpack
79+instance Literal Lazy.Text where literal = fromString . Lazy.Text.unpack
80+instance ToParam (Enumerated enum) (PG (Enumerated enum))
81+ => Literal (Enumerated enum) where
82+ literal
83+ = UnsafeExpression
84+ . singleQuotedUtf8
85+ . builderBytes
86+ . unK
87+ . toParam @(Enumerated enum) @(PG (Enumerated enum))
squeal-postgresql/src/Squeal/PostgreSQL/Expression/Logic.hsnew file+105
@@ -0,0 +1,105 @@
1+{-|
2+Module: Squeal.PostgreSQL.Expression.Logic
3+Description: Logical expressions
4+Copyright: (c) Eitan Chatav, 2019
5+Maintainer: eitan@morphism.tech
6+Stability: experimental
7+
8+Logical expressions and operators
9+-}
10+
11+{-# LANGUAGE
12+ DataKinds
13+ , OverloadedStrings
14+ , TypeOperators
15+#-}
16+
17+module Squeal.PostgreSQL.Expression.Logic
18+ ( Condition
19+ , true
20+ , false
21+ , not_
22+ , (.&&)
23+ , (.||)
24+ , caseWhenThenElse
25+ , ifThenElse
26+ ) where
27+
28+import Squeal.PostgreSQL.Expression
29+import Squeal.PostgreSQL.Render
30+import Squeal.PostgreSQL.Schema
31+
32+-- | A `Condition` is an `Expression`, which can evaluate
33+-- to `true`, `false` or `Squeal.PostgreSQL.Null.null_`. This is because SQL uses
34+-- a three valued logic.
35+type Condition outer commons grp schemas params from =
36+ Expression outer commons grp schemas params from ('Null 'PGbool)
37+
38+-- | >>> printSQL true
39+-- TRUE
40+true :: Expr (null 'PGbool)
41+true = UnsafeExpression "TRUE"
42+
43+-- | >>> printSQL false
44+-- FALSE
45+false :: Expr (null 'PGbool)
46+false = UnsafeExpression "FALSE"
47+
48+-- | >>> printSQL $ not_ true
49+-- (NOT TRUE)
50+not_ :: null 'PGbool --> null 'PGbool
51+not_ = unsafeLeftOp "NOT"
52+
53+-- | >>> printSQL $ true .&& false
54+-- (TRUE AND FALSE)
55+(.&&) :: Operator (null 'PGbool) (null 'PGbool) (null 'PGbool)
56+infixr 3 .&&
57+(.&&) = unsafeBinaryOp "AND"
58+
59+-- | >>> printSQL $ true .|| false
60+-- (TRUE OR FALSE)
61+(.||) :: Operator (null 'PGbool) (null 'PGbool) (null 'PGbool)
62+infixr 2 .||
63+(.||) = unsafeBinaryOp "OR"
64+
65+-- | >>> :{
66+-- let
67+-- expression :: Expression outer commons grp schemas params from (null 'PGint2)
68+-- expression = caseWhenThenElse [(true, 1), (false, 2)] 3
69+-- in printSQL expression
70+-- :}
71+-- CASE WHEN TRUE THEN 1 WHEN FALSE THEN 2 ELSE 3 END
72+caseWhenThenElse
73+ :: [ ( Condition outer commons grp schemas params from
74+ , Expression outer commons grp schemas params from ty
75+ ) ]
76+ -- ^ whens and thens
77+ -> Expression outer commons grp schemas params from ty
78+ -- ^ else
79+ -> Expression outer commons grp schemas params from ty
80+caseWhenThenElse whenThens else_ = UnsafeExpression $ mconcat
81+ [ "CASE"
82+ , mconcat
83+ [ mconcat
84+ [ " WHEN ", renderSQL when_
85+ , " THEN ", renderSQL then_
86+ ]
87+ | (when_,then_) <- whenThens
88+ ]
89+ , " ELSE ", renderSQL else_
90+ , " END"
91+ ]
92+
93+-- | >>> :{
94+-- let
95+-- expression :: Expression outer commons grp schemas params from (null 'PGint2)
96+-- expression = ifThenElse true 1 0
97+-- in printSQL expression
98+-- :}
99+-- CASE WHEN TRUE THEN 1 ELSE 0 END
100+ifThenElse
101+ :: Condition outer commons grp schemas params from
102+ -> Expression outer commons grp schemas params from ty -- ^ then
103+ -> Expression outer commons grp schemas params from ty -- ^ else
104+ -> Expression outer commons grp schemas params from ty
105+ifThenElse if_ then_ else_ = caseWhenThenElse [(if_,then_)] else_
squeal-postgresql/src/Squeal/PostgreSQL/Expression/Math.hsnew file+100
@@ -0,0 +1,100 @@
1+{-|
2+Module: Squeal.PostgreSQL.Expression.Math
3+Description: Math expressions
4+Copyright: (c) Eitan Chatav, 2019
5+Maintainer: eitan@morphism.tech
6+Stability: experimental
7+
8+Mathematical functions and operators
9+-}
10+
11+{-# LANGUAGE
12+ DataKinds
13+ , OverloadedStrings
14+ , TypeOperators
15+#-}
16+
17+module Squeal.PostgreSQL.Expression.Math
18+ ( atan2_
19+ , quot_
20+ , rem_
21+ , trunc
22+ , round_
23+ , ceiling_
24+ ) where
25+
26+import Squeal.PostgreSQL.Expression
27+import Squeal.PostgreSQL.List
28+import Squeal.PostgreSQL.Schema
29+
30+-- $setup
31+-- >>> import Squeal.PostgreSQL
32+
33+-- | >>> :{
34+-- let
35+-- expression :: Expr (null 'PGfloat4)
36+-- expression = atan2_ (pi *: 2)
37+-- in printSQL expression
38+-- :}
39+-- atan2(pi(), 2)
40+atan2_ :: float `In` PGFloating => '[ null float, null float] ---> null float
41+atan2_ = unsafeFunctionN "atan2"
42+
43+
44+-- | integer division, truncates the result
45+--
46+-- >>> :{
47+-- let
48+-- expression :: Expression outer commons grp schemas params from (null 'PGint2)
49+-- expression = 5 `quot_` 2
50+-- in printSQL expression
51+-- :}
52+-- (5 / 2)
53+quot_
54+ :: int `In` PGIntegral
55+ => Operator (null int) (null int) (null int)
56+quot_ = unsafeBinaryOp "/"
57+
58+-- | remainder upon integer division
59+--
60+-- >>> :{
61+-- let
62+-- expression :: Expression outer commons grp schemas params from (null 'PGint2)
63+-- expression = 5 `rem_` 2
64+-- in printSQL expression
65+-- :}
66+-- (5 % 2)
67+rem_
68+ :: int `In` PGIntegral
69+ => Operator (null int) (null int) (null int)
70+rem_ = unsafeBinaryOp "%"
71+
72+-- | >>> :{
73+-- let
74+-- expression :: Expression outer commons grp schemas params from (null 'PGfloat4)
75+-- expression = trunc pi
76+-- in printSQL expression
77+-- :}
78+-- trunc(pi())
79+trunc :: frac `In` PGFloating => null frac --> null frac
80+trunc = unsafeFunction "trunc"
81+
82+-- | >>> :{
83+-- let
84+-- expression :: Expression outer commons grp schemas params from (null 'PGfloat4)
85+-- expression = round_ pi
86+-- in printSQL expression
87+-- :}
88+-- round(pi())
89+round_ :: frac `In` PGFloating => null frac --> null frac
90+round_ = unsafeFunction "round"
91+
92+-- | >>> :{
93+-- let
94+-- expression :: Expression outer commons grp schemas params from (null 'PGfloat4)
95+-- expression = ceiling_ pi
96+-- in printSQL expression
97+-- :}
98+-- ceiling(pi())
99+ceiling_ :: frac `In` PGFloating => null frac --> null frac
100+ceiling_ = unsafeFunction "ceiling"
squeal-postgresql/src/Squeal/PostgreSQL/Expression/Null.hsnew file+104
@@ -0,0 +1,104 @@
1+{-|
2+Module: Squeal.PostgreSQL.Expression.Null
3+Description: Null
4+Copyright: (c) Eitan Chatav, 2019
5+Maintainer: eitan@morphism.tech
6+Stability: experimental
7+
8+Null values and null handling functions
9+-}
10+
11+{-# LANGUAGE
12+ DataKinds
13+ , OverloadedStrings
14+ , TypeOperators
15+#-}
16+
17+module Squeal.PostgreSQL.Expression.Null
18+ ( null_
19+ , notNull
20+ , coalesce
21+ , fromNull
22+ , isNull
23+ , isNotNull
24+ , matchNull
25+ , nullIf
26+ ) where
27+
28+import Squeal.PostgreSQL.Expression
29+import Squeal.PostgreSQL.Expression.Logic
30+import Squeal.PostgreSQL.Render
31+import Squeal.PostgreSQL.Schema
32+
33+-- $setup
34+-- >>> import Squeal.PostgreSQL
35+
36+-- | analagous to `Nothing`
37+--
38+-- >>> printSQL null_
39+-- NULL
40+null_ :: Expr ('Null ty)
41+null_ = UnsafeExpression "NULL"
42+
43+-- | analagous to `Just`
44+--
45+-- >>> printSQL $ notNull true
46+-- TRUE
47+notNull :: 'NotNull ty --> 'Null ty
48+notNull = UnsafeExpression . renderSQL
49+
50+-- | return the leftmost value which is not NULL
51+--
52+-- >>> printSQL $ coalesce [null_, true] false
53+-- COALESCE(NULL, TRUE, FALSE)
54+coalesce :: FunctionVar ('Null ty) ('NotNull ty) ('NotNull ty)
55+coalesce nullxs notNullx = UnsafeExpression $
56+ "COALESCE" <> parenthesized (commaSeparated
57+ ((renderSQL <$> nullxs) <> [renderSQL notNullx]))
58+
59+-- | analagous to `Data.Maybe.fromMaybe` using @COALESCE@
60+--
61+-- >>> printSQL $ fromNull true null_
62+-- COALESCE(NULL, TRUE)
63+fromNull
64+ :: Expression outer commons grp schemas params from ('NotNull ty)
65+ -- ^ what to convert @NULL@ to
66+ -> Expression outer commons grp schemas params from ('Null ty)
67+ -> Expression outer commons grp schemas params from ('NotNull ty)
68+fromNull notNullx nullx = coalesce [nullx] notNullx
69+
70+-- | >>> printSQL $ null_ & isNull
71+-- NULL IS NULL
72+isNull :: 'Null ty --> null 'PGbool
73+isNull x = UnsafeExpression $ renderSQL x <+> "IS NULL"
74+
75+-- | >>> printSQL $ null_ & isNotNull
76+-- NULL IS NOT NULL
77+isNotNull :: 'Null ty --> null 'PGbool
78+isNotNull x = UnsafeExpression $ renderSQL x <+> "IS NOT NULL"
79+
80+-- | analagous to `maybe` using @IS NULL@
81+--
82+-- >>> printSQL $ matchNull true not_ null_
83+-- CASE WHEN NULL IS NULL THEN TRUE ELSE (NOT NULL) END
84+matchNull
85+ :: Expression outer commons grp schemas params from (nullty)
86+ -- ^ what to convert @NULL@ to
87+ -> ( Expression outer commons grp schemas params from ('NotNull ty)
88+ -> Expression outer commons grp schemas params from (nullty) )
89+ -- ^ function to perform when @NULL@ is absent
90+ -> Expression outer commons grp schemas params from ('Null ty)
91+ -> Expression outer commons grp schemas params from (nullty)
92+matchNull y f x = ifThenElse (isNull x) y
93+ (f (UnsafeExpression (renderSQL x)))
94+
95+{-| right inverse to `fromNull`, if its arguments are equal then
96+`nullIf` gives @NULL@.
97+
98+>>> :set -XTypeApplications -XDataKinds
99+>>> let expr = nullIf (false *: param @1) :: Expression outer commons grp schemas '[ 'NotNull 'PGbool] from ('Null 'PGbool)
100+>>> printSQL expr
101+NULLIF(FALSE, ($1 :: bool))
102+-}
103+nullIf :: '[ 'NotNull ty, 'NotNull ty] ---> 'Null ty
104+nullIf = unsafeFunctionN "NULLIF"
squeal-postgresql/src/Squeal/PostgreSQL/Expression/Parameter.hsnew file+80
@@ -0,0 +1,80 @@
1+{-|
2+Module: Squeal.PostgreSQL.Expression.Parameter
3+Description: Parameters
4+Copyright: (c) Eitan Chatav, 2019
5+Maintainer: eitan@morphism.tech
6+Stability: experimental
7+
8+Parameters, out-of-line data values
9+-}
10+
11+{-# LANGUAGE
12+ AllowAmbiguousTypes
13+ , DataKinds
14+ , FlexibleContexts
15+ , FlexibleInstances
16+ , FunctionalDependencies
17+ , KindSignatures
18+ , MultiParamTypeClasses
19+ , OverloadedStrings
20+ , RankNTypes
21+ , ScopedTypeVariables
22+ , TypeApplications
23+ , TypeOperators
24+ , UndecidableInstances
25+#-}
26+
27+module Squeal.PostgreSQL.Expression.Parameter
28+ ( HasParameter (parameter)
29+ , param
30+ ) where
31+
32+import GHC.TypeLits
33+
34+import Squeal.PostgreSQL.Expression
35+import Squeal.PostgreSQL.Expression.Type
36+import Squeal.PostgreSQL.Render
37+import Squeal.PostgreSQL.Schema
38+
39+-- $setup
40+-- >>> import Squeal.PostgreSQL
41+
42+{- | A `HasParameter` constraint is used to indicate a value that is
43+supplied externally to a SQL statement.
44+`Squeal.PostgreSQL.PQ.manipulateParams`,
45+`Squeal.PostgreSQL.PQ.queryParams` and
46+`Squeal.PostgreSQL.PQ.traversePrepared` support specifying data values
47+separately from the SQL command string, in which case `param`s are used to
48+refer to the out-of-line data values.
49+-}
50+class KnownNat n => HasParameter
51+ (n :: Nat)
52+ (params :: [NullityType])
53+ (ty :: NullityType)
54+ | n params -> ty where
55+ -- | `parameter` takes a `Nat` using type application and a `TypeExpression`.
56+ --
57+ -- >>> let expr = parameter @1 int4 :: Expression outer '[] grp schemas '[ 'Null 'PGint4] from ('Null 'PGint4)
58+ -- >>> printSQL expr
59+ -- ($1 :: int4)
60+ parameter
61+ :: TypeExpression schemas ty
62+ -> Expression outer commons grp schemas params from ty
63+ parameter ty = UnsafeExpression $ parenthesized $
64+ "$" <> renderNat @n <+> "::"
65+ <+> renderSQL ty
66+instance {-# OVERLAPPING #-} HasParameter 1 (ty1:tys) ty1
67+instance {-# OVERLAPPABLE #-} (KnownNat n, HasParameter (n-1) params ty)
68+ => HasParameter n (ty' : params) ty
69+
70+-- | `param` takes a `Nat` using type application and for basic types,
71+-- infers a `TypeExpression`.
72+--
73+-- >>> let expr = param @1 :: Expression outer commons grp schemas '[ 'Null 'PGint4] from ('Null 'PGint4)
74+-- >>> printSQL expr
75+-- ($1 :: int4)
76+param
77+ :: forall n outer commons schemas params from grp ty
78+ . (PGTyped schemas ty, HasParameter n params ty)
79+ => Expression outer commons grp schemas params from ty -- ^ param
80+param = parameter @n (pgtype @schemas)
squeal-postgresql/src/Squeal/PostgreSQL/Expression/Range.hsnew file+230
@@ -0,0 +1,230 @@
1+{-|
2+Module: Squeal.PostgreSQL.Expression.Range
3+Description: range types and functions
4+Copyright: (c) Eitan Chatav, 2019
5+Maintainer: eitan@morphism.tech
6+Stability: experimental
7+
8+Range types and functions
9+-}
10+
11+{-# LANGUAGE
12+ AllowAmbiguousTypes
13+ , DataKinds
14+ , DeriveAnyClass
15+ , DeriveGeneric
16+ , DeriveFoldable
17+ , DerivingStrategies
18+ , DeriveTraversable
19+ , FlexibleContexts
20+ , FlexibleInstances
21+ , LambdaCase
22+ , MultiParamTypeClasses
23+ , OverloadedLabels
24+ , OverloadedStrings
25+ , PatternSynonyms
26+ , RankNTypes
27+ , ScopedTypeVariables
28+ , TypeApplications
29+ , TypeFamilies
30+ , TypeOperators
31+ , UndecidableInstances
32+#-}
33+
34+module Squeal.PostgreSQL.Expression.Range
35+ ( range
36+ , Range (..)
37+ , (<=..<=), (<..<), (<=..<), (<..<=)
38+ , moreThan, atLeast, lessThan, atMost
39+ , singleton, whole
40+ , Bound (..)
41+ , (.<@)
42+ , (@>.)
43+ , (<<@)
44+ , (@>>)
45+ , (&<)
46+ , (&>)
47+ , (-|-)
48+ , (@+)
49+ , (@*)
50+ , (@-)
51+ , lowerBound
52+ , upperBound
53+ , isEmpty
54+ , lowerInc
55+ , lowerInf
56+ , upperInc
57+ , upperInf
58+ , rangeMerge
59+ ) where
60+
61+import BinaryParser
62+import ByteString.StrictBuilder
63+import Data.Bits
64+import qualified GHC.Generics as GHC
65+import qualified Generics.SOP as SOP
66+import qualified PostgreSQL.Binary.Decoding as Decoding
67+
68+import Squeal.PostgreSQL.Binary
69+import Squeal.PostgreSQL.Expression
70+import Squeal.PostgreSQL.Expression.Type hiding (bool)
71+import Squeal.PostgreSQL.PG
72+import Squeal.PostgreSQL.Render
73+import Squeal.PostgreSQL.Schema
74+
75+-- $setup
76+-- >>> import Squeal.PostgreSQL
77+
78+-- | Construct a `range`
79+--
80+-- >>> printSQL $ range tstzrange (atLeast now)
81+-- tstzrange(now(), NULL, '[)')
82+-- >>> printSQL $ range numrange (0 <=..< 2*pi)
83+-- numrange(0, (2 * pi()), '[)')
84+-- >>> printSQL $ range int4range Empty
85+-- ('empty' :: int4range)
86+range
87+ :: TypeExpression schemas (null ('PGrange ty))
88+ -> Range (Expression outer commons grp schemas params from ('NotNull ty))
89+ -> Expression outer commons grp schemas params from (null ('PGrange ty))
90+range ty = \case
91+ Empty -> UnsafeExpression $ parenthesized
92+ (emp <+> "::" <+> renderSQL ty)
93+ NonEmpty l u -> UnsafeExpression $ renderSQL ty <> parenthesized
94+ (commaSeparated (args l u))
95+ where
96+ emp = singleQuote <> "empty" <> singleQuote
97+ args l u = [arg l, arg u, singleQuote <> bra l <> ket u <> singleQuote]
98+ singleQuote = "\'"
99+ arg = \case
100+ Infinite -> "NULL"; Closed x -> renderSQL x; Open x -> renderSQL x
101+ bra = \case Infinite -> "("; Closed _ -> "["; Open _ -> "("
102+ ket = \case Infinite -> ")"; Closed _ -> "]"; Open _ -> ")"
103+
104+data Bound x = Infinite | Closed x | Open x
105+ deriving
106+ ( Eq, Ord, Show, Read, GHC.Generic
107+ , Functor, Foldable, Traversable )
108+
109+data Range x = Empty | NonEmpty (Bound x) (Bound x)
110+ deriving
111+ ( Eq, Ord, Show, Read, GHC.Generic
112+ , Functor, Foldable, Traversable )
113+ deriving anyclass (SOP.Generic, SOP.HasDatatypeInfo)
114+type instance PG (Range x) = 'PGrange (PG x)
115+instance ToParam x pg => ToParam (Range x) ('PGrange pg) where
116+ toParam rng = K $
117+ word8 (setFlags rng 0) <>
118+ case rng of
119+ Empty -> mempty
120+ NonEmpty lower upper -> putBound lower <> putBound upper
121+ where
122+ putBound = \case
123+ Infinite -> mempty
124+ Closed value -> putValue (unK (toParam @x @pg value))
125+ Open value -> putValue (unK (toParam @x @pg value))
126+ putValue value = int32BE (fromIntegral (builderLength value)) <> value
127+ setFlags = \case
128+ Empty -> (`setBit` 0)
129+ NonEmpty lower upper ->
130+ setLowerFlags lower . setUpperFlags upper
131+ setLowerFlags = \case
132+ Infinite -> (`setBit` 3)
133+ Closed _ -> (`setBit` 1)
134+ Open _ -> id
135+ setUpperFlags = \case
136+ Infinite -> (`setBit` 4)
137+ Closed _ -> (`setBit` 2)
138+ Open _ -> id
139+instance FromValue pg y => FromValue ('PGrange pg) (Range y) where
140+ fromValue = do
141+ flag <- byte
142+ if testBit flag 0 then return Empty else do
143+ lower <-
144+ if testBit flag 3
145+ then return Infinite
146+ else do
147+ len <- sized 4 Decoding.int
148+ l <- sized len (fromValue @pg)
149+ return $ if testBit flag 1 then Closed l else Open l
150+ upper <-
151+ if testBit flag 4
152+ then return Infinite
153+ else do
154+ len <- sized 4 Decoding.int
155+ l <- sized len (fromValue @pg)
156+ return $ if testBit flag 2 then Closed l else Open l
157+ return $ NonEmpty lower upper
158+
159+(<=..<=), (<..<), (<=..<), (<..<=) :: x -> x -> Range x
160+infix 4 <=..<=, <..<, <=..<, <..<=
161+x <=..<= y = NonEmpty (Closed x) (Closed y)
162+x <..< y = NonEmpty (Open x) (Open y)
163+x <=..< y = NonEmpty (Closed x) (Open y)
164+x <..<= y = NonEmpty (Open x) (Closed y)
165+
166+moreThan, atLeast, lessThan, atMost :: x -> Range x
167+moreThan x = NonEmpty (Open x) Infinite
168+atLeast x = NonEmpty (Closed x) Infinite
169+lessThan x = NonEmpty Infinite (Open x)
170+atMost x = NonEmpty Infinite (Closed x)
171+
172+singleton :: x -> Range x
173+singleton x = x <=..<= x
174+
175+whole :: Range x
176+whole = NonEmpty Infinite Infinite
177+
178+(.<@) :: Operator ('NotNull ty) (null ('PGrange ty)) ('Null 'PGbool)
179+(.<@) = unsafeBinaryOp "<@"
180+
181+(@>.) :: Operator (null ('PGrange ty)) ('NotNull ty) ('Null 'PGbool)
182+(@>.) = unsafeBinaryOp "<@"
183+
184+(<<@) :: Operator (null ('PGrange ty)) (null ('PGrange ty)) ('Null 'PGbool)
185+(<<@) = unsafeBinaryOp "<<"
186+
187+(@>>) :: Operator (null ('PGrange ty)) (null ('PGrange ty)) ('Null 'PGbool)
188+(@>>) = unsafeBinaryOp ">>"
189+
190+(&<) :: Operator (null ('PGrange ty)) (null ('PGrange ty)) ('Null 'PGbool)
191+(&<) = unsafeBinaryOp "&<"
192+
193+(&>) :: Operator (null ('PGrange ty)) (null ('PGrange ty)) ('Null 'PGbool)
194+(&>) = unsafeBinaryOp "&>"
195+
196+(-|-) :: Operator (null ('PGrange ty)) (null ('PGrange ty)) ('Null 'PGbool)
197+(-|-) = unsafeBinaryOp "-|-"
198+
199+(@+) :: Operator (null ('PGrange ty)) (null ('PGrange ty)) (null ('PGrange ty))
200+(@+) = unsafeBinaryOp "+"
201+
202+(@*) :: Operator (null ('PGrange ty)) (null ('PGrange ty)) (null ('PGrange ty))
203+(@*) = unsafeBinaryOp "*"
204+
205+(@-) :: Operator (null ('PGrange ty)) (null ('PGrange ty)) (null ('PGrange ty))
206+(@-) = unsafeBinaryOp "-"
207+
208+lowerBound :: null ('PGrange ty) --> 'Null ty
209+lowerBound = unsafeFunction "lower"
210+
211+upperBound :: null ('PGrange ty) --> 'Null ty
212+upperBound = unsafeFunction "upper"
213+
214+isEmpty :: null ('PGrange ty) --> 'Null 'PGbool
215+isEmpty = unsafeFunction "isempty"
216+
217+lowerInc :: null ('PGrange ty) --> 'Null 'PGbool
218+lowerInc = unsafeFunction "lower_inc"
219+
220+lowerInf :: null ('PGrange ty) --> 'Null 'PGbool
221+lowerInf = unsafeFunction "lower_inf"
222+
223+upperInc :: null ('PGrange ty) --> 'Null 'PGbool
224+upperInc = unsafeFunction "upper_inc"
225+
226+upperInf :: null ('PGrange ty) --> 'Null 'PGbool
227+upperInf = unsafeFunction "upper_inf"
228+
229+rangeMerge :: '[null ('PGrange ty), null ('PGrange ty)] ---> null ('PGrange ty)
230+rangeMerge = unsafeFunctionN "range_merge"
squeal-postgresql/src/Squeal/PostgreSQL/Expression/Set.hsnew file+139
@@ -0,0 +1,139 @@
1+{-|
2+Module: Squeal.PostgreSQL.Expression.Set
3+Description: Set returning functions
4+Copyright: (c) Eitan Chatav, 2019
5+Maintainer: eitan@morphism.tech
6+Stability: experimental
7+
8+Set returning functions
9+-}
10+
11+{-# LANGUAGE
12+ AllowAmbiguousTypes
13+ , DataKinds
14+ , FlexibleContexts
15+ , OverloadedStrings
16+ , PolyKinds
17+ , RankNTypes
18+ , ScopedTypeVariables
19+ , TypeApplications
20+ , TypeOperators
21+#-}
22+
23+module Squeal.PostgreSQL.Expression.Set
24+ ( generateSeries
25+ , generateSeriesStep
26+ , generateSeriesTimestamp
27+ , SetFunction
28+ , unsafeSetFunction
29+ , SetFunctionDB
30+ , setFunction
31+ , SetFunctionN
32+ , unsafeSetFunctionN
33+ , SetFunctionNDB
34+ , setFunctionN
35+ ) where
36+
37+import GHC.TypeLits
38+
39+import qualified Generics.SOP as SOP
40+
41+import Squeal.PostgreSQL.Alias
42+import Squeal.PostgreSQL.Expression
43+import Squeal.PostgreSQL.List
44+import Squeal.PostgreSQL.Render
45+import Squeal.PostgreSQL.Query
46+import Squeal.PostgreSQL.Schema
47+
48+{- |
49+A @RankNType@ for set returning functions with 1 argument.
50+-}
51+type SetFunction fun ty row
52+ = forall outer commons schemas params
53+ . Expression outer commons 'Ungrouped schemas params '[] ty
54+ -- ^ input
55+ -> FromClause outer commons schemas params '[fun ::: row]
56+ -- ^ output
57+
58+type SetFunctionDB fun schemas ty row
59+ = forall outer commons params
60+ . Expression outer commons 'Ungrouped schemas params '[] ty
61+ -- ^ input
62+ -> FromClause outer commons schemas params '[fun ::: row]
63+ -- ^ output
64+
65+-- | Escape hatch for a set returning function with 1 argument.
66+unsafeSetFunction
67+ :: forall fun ty row. KnownSymbol fun
68+ => SetFunction fun ty row -- ^ set returning function
69+unsafeSetFunction x = UnsafeFromClause $
70+ renderSymbol @fun <> parenthesized (renderSQL x)
71+
72+setFunction
73+ :: ( Has sch schemas schema
74+ , Has fun schema ('Function ('[ty] :=> 'ReturnsTable row)) )
75+ => QualifiedAlias sch fun
76+ -> SetFunctionDB fun schemas ty row
77+setFunction _ = unsafeSetFunction
78+
79+{- |
80+A @RankNType@ for set returning functions with multiple argument.
81+-}
82+type SetFunctionN fun tys row
83+ = forall outer commons schemas params
84+ . NP (Expression outer commons 'Ungrouped schemas params '[]) tys
85+ -- ^ inputs
86+ -> FromClause outer commons schemas params '[fun ::: row]
87+ -- ^ output
88+
89+-- | Escape hatch for a set returning function with multiple argument.
90+unsafeSetFunctionN
91+ :: forall fun tys row. (SOP.SListI tys, KnownSymbol fun)
92+ => SetFunctionN fun tys row -- ^ set returning function
93+unsafeSetFunctionN xs = UnsafeFromClause $
94+ renderSymbol @fun <> parenthesized (renderCommaSeparated renderSQL xs)
95+
96+type SetFunctionNDB fun schemas tys row
97+ = forall outer commons params
98+ . NP (Expression outer commons 'Ungrouped schemas params '[]) tys
99+ -- ^ inputs
100+ -> FromClause outer commons schemas params '[fun ::: row]
101+ -- ^ output
102+
103+setFunctionN
104+ :: ( Has sch schemas schema
105+ , Has fun schema ('Function (tys :=> 'ReturnsTable row))
106+ , SOP.SListI tys )
107+ => QualifiedAlias sch fun
108+ -> SetFunctionNDB fun schemas tys row
109+setFunctionN _ = unsafeSetFunctionN
110+
111+{- | @generateSeries (start *: stop)@
112+
113+Generate a series of values, from @start@ to @stop@ with a step size of one
114+-}
115+generateSeries
116+ :: ty `In` '[ 'PGint4, 'PGint8, 'PGnumeric]
117+ => SetFunctionN "generate_series" '[ null ty, null ty]
118+ '["generate_series" ::: null ty] -- ^ set returning function
119+generateSeries = unsafeSetFunctionN
120+
121+{- | @generateSeries (start :* stop *: step)@
122+
123+Generate a series of values, from @start@ to @stop@ with a step size of @step@
124+-}
125+generateSeriesStep
126+ :: ty `In` '[ 'PGint4, 'PGint8, 'PGnumeric]
127+ => SetFunctionN "generate_series" '[null ty, null ty, null ty]
128+ '["generate_series" ::: null ty] -- ^ set returning function
129+generateSeriesStep = unsafeSetFunctionN
130+
131+{- | @generateSeries (start :* stop *: step)@
132+
133+Generate a series of values, from @start@ to @stop@ with a step size of @step@
134+-}
135+generateSeriesTimestamp
136+ :: ty `In` '[ 'PGtimestamp, 'PGtimestamptz]
137+ => SetFunctionN "generate_series" '[null ty, null ty, null 'PGinterval]
138+ '["generate_series" ::: null ty] -- ^ set returning function
139+generateSeriesTimestamp = unsafeSetFunctionN
squeal-postgresql/src/Squeal/PostgreSQL/Expression/Sort.hsnew file+85
@@ -0,0 +1,85 @@
1+{-|
2+Module: Squeal.PostgreSQL.Expression.Sort
3+Description: Sort expressions
4+Copyright: (c) Eitan Chatav, 2019
5+Maintainer: eitan@morphism.tech
6+Stability: experimental
7+
8+Sort expressions
9+-}
10+
11+{-# LANGUAGE
12+ DataKinds
13+ , GADTs
14+ , LambdaCase
15+ , OverloadedStrings
16+ , StandaloneDeriving
17+#-}
18+
19+module Squeal.PostgreSQL.Expression.Sort
20+ ( SortExpression (..)
21+ , OrderBy (..)
22+ ) where
23+
24+import Squeal.PostgreSQL.Expression
25+import Squeal.PostgreSQL.Render
26+import Squeal.PostgreSQL.Schema
27+
28+-- | `SortExpression`s are used by `orderBy` to optionally sort the results
29+-- of a `Squeal.PostgreSQL.Query.Query`. `Asc` or `Desc`
30+-- set the sort direction of a `NotNull` result
31+-- column to ascending or descending. Ascending order puts smaller values
32+-- first, where "smaller" is defined in terms of the
33+-- `Squeal.PostgreSQL.Expression.Comparison..<` operator. Similarly,
34+-- descending order is determined with the
35+-- `Squeal.PostgreSQL.Expression.Comparison..>` operator. `AscNullsFirst`,
36+-- `AscNullsLast`, `DescNullsFirst` and `DescNullsLast` options are used to
37+-- determine whether nulls appear before or after non-null values in the sort
38+-- ordering of a `Null` result column.
39+data SortExpression outer commons grp schemas params from where
40+ Asc
41+ :: Expression outer commons grp schemas params from ('NotNull ty)
42+ -> SortExpression outer commons grp schemas params from
43+ Desc
44+ :: Expression outer commons grp schemas params from ('NotNull ty)
45+ -> SortExpression outer commons grp schemas params from
46+ AscNullsFirst
47+ :: Expression outer commons grp schemas params from ('Null ty)
48+ -> SortExpression outer commons grp schemas params from
49+ AscNullsLast
50+ :: Expression outer commons grp schemas params from ('Null ty)
51+ -> SortExpression outer commons grp schemas params from
52+ DescNullsFirst
53+ :: Expression outer commons grp schemas params from ('Null ty)
54+ -> SortExpression outer commons grp schemas params from
55+ DescNullsLast
56+ :: Expression outer commons grp schemas params from ('Null ty)
57+ -> SortExpression outer commons grp schemas params from
58+deriving instance Show (SortExpression outer commons grp schemas params from)
59+instance RenderSQL (SortExpression outer commons grp schemas params from) where
60+ renderSQL = \case
61+ Asc expression -> renderSQL expression <+> "ASC"
62+ Desc expression -> renderSQL expression <+> "DESC"
63+ AscNullsFirst expression -> renderSQL expression
64+ <+> "ASC NULLS FIRST"
65+ DescNullsFirst expression -> renderSQL expression
66+ <+> "DESC NULLS FIRST"
67+ AscNullsLast expression -> renderSQL expression <+> "ASC NULLS LAST"
68+ DescNullsLast expression -> renderSQL expression <+> "DESC NULLS LAST"
69+
70+{- |
71+The `orderBy` clause causes the result rows of a `Squeal.PostgreSQL.Query.TableExpression`
72+to be sorted according to the specified `SortExpression`(s).
73+If two rows are equal according to the leftmost expression,
74+they are compared according to the next expression and so on.
75+If they are equal according to all specified expressions,
76+they are returned in an implementation-dependent order.
77+
78+You can also control the order in which rows are processed by window functions
79+using `orderBy` within `Squeal.PostgreSQL.Query.Over`.
80+-}
81+class OrderBy expr where
82+ orderBy
83+ :: [SortExpression outer commons grp schemas params from]
84+ -> expr outer commons grp schemas params from
85+ -> expr outer commons grp schemas params from
squeal-postgresql/src/Squeal/PostgreSQL/Expression/Subquery.hsnew file+120
@@ -0,0 +1,120 @@
1+{-|
2+Module: Squeal.PostgreSQL.Expression.Subquery
3+Description: Subquery expressions
4+Copyright: (c) Eitan Chatav, 2019
5+Maintainer: eitan@morphism.tech
6+Stability: experimental
7+
8+Subquery expressions
9+-}
10+
11+{-# LANGUAGE
12+ DataKinds
13+ , OverloadedStrings
14+ , RankNTypes
15+ , TypeOperators
16+#-}
17+
18+module Squeal.PostgreSQL.Expression.Subquery
19+ ( exists
20+ , in_
21+ , notIn
22+ , subAll
23+ , subAny
24+ ) where
25+
26+import Squeal.PostgreSQL.Alias
27+import Squeal.PostgreSQL.Expression
28+import Squeal.PostgreSQL.Expression.Logic
29+import Squeal.PostgreSQL.List
30+import Squeal.PostgreSQL.Query
31+import Squeal.PostgreSQL.Render
32+import Squeal.PostgreSQL.Schema
33+
34+-- $setup
35+-- >>> import Squeal.PostgreSQL
36+
37+{- |
38+The argument of `exists` is an arbitrary subquery. The subquery is evaluated
39+to determine whether it returns any rows. If it returns at least one row,
40+the result of `exists` is `true`; if the subquery returns no rows,
41+the result of `exists` is `false`.
42+
43+The subquery can refer to variables from the surrounding query,
44+which will act as constants during any one evaluation of the subquery.
45+
46+The subquery will generally only be executed long enough to determine whether
47+at least one row is returned, not all the way to completion.
48+-}
49+exists
50+ :: Query (Join outer from) commons schemas params row
51+ -> Condition outer commons grp schemas params from
52+exists query = UnsafeExpression $ "EXISTS" <+> parenthesized (renderSQL query)
53+
54+{- |
55+The right-hand side is a parenthesized subquery, which must return
56+exactly one column. The left-hand expression is evaluated and compared to each
57+row of the subquery result using the given `Operator`,
58+which must yield a Boolean result. The result of `subAll` is `true`
59+if all rows yield true (including the case where the subquery returns no rows).
60+The result is `false` if any `false` result is found.
61+The result is `Squeal.PostgreSQL.Expression.Null.null_` if
62+ no comparison with a subquery row returns `false`,
63+and at least one comparison returns `Squeal.PostgreSQL.Expression.Null.null_`.
64+
65+>>> printSQL $ subAll true (.==) (values_ (true `as` #foo))
66+(TRUE = ALL (SELECT * FROM (VALUES (TRUE)) AS t ("foo")))
67+-}
68+subAll
69+ :: Expression outer commons grp schemas params from ty1 -- ^ expression
70+ -> Operator ty1 ty2 ('Null 'PGbool) -- ^ operator
71+ -> Query (Join outer from) commons schemas params '[col ::: ty2] -- ^ subquery
72+ -> Condition outer commons grp schemas params from
73+subAll expr (?) qry = expr ?
74+ (UnsafeExpression $ "ALL" <+> parenthesized (renderSQL qry))
75+
76+{- |
77+The right-hand side is a parenthesized subquery, which must return exactly one column.
78+The left-hand expression is evaluated and compared to each row of the subquery result
79+using the given `Operator`, which must yield a Boolean result. The result of `subAny` is `true`
80+if any `true` result is obtained. The result is `false` if no true result is found
81+(including the case where the subquery returns no rows).
82+
83+>>> printSQL $ subAny "foo" like (values_ ("foobar" `as` #foo))
84+(E'foo' LIKE ANY (SELECT * FROM (VALUES (E'foobar')) AS t ("foo")))
85+-}
86+subAny
87+ :: Expression outer commons grp schemas params from ty1 -- ^ expression
88+ -> Operator ty1 ty2 ('Null 'PGbool) -- ^ operator
89+ -> Query (Join outer from) commons schemas params '[col ::: ty2] -- ^ subquery
90+ -> Condition outer commons grp schemas params from
91+subAny expr (?) qry = expr ?
92+ (UnsafeExpression $ "ANY" <+> parenthesized (renderSQL qry))
93+
94+{- |
95+The result is `true` if the left-hand expression's result is equal
96+to any of the right-hand expressions.
97+
98+>>> printSQL $ true `in_` [true, false, null_]
99+TRUE IN (TRUE, FALSE, NULL)
100+-}
101+in_
102+ :: Expression outer commons grp schemas params from ty -- ^ expression
103+ -> [Expression outer commons grp schemas params from ty]
104+ -> Condition outer commons grp schemas params from
105+expr `in_` exprs = UnsafeExpression $ renderSQL expr <+> "IN"
106+ <+> parenthesized (commaSeparated (renderSQL <$> exprs))
107+
108+{- |
109+The result is `true` if the left-hand expression's result is not equal
110+to any of the right-hand expressions.
111+
112+>>> printSQL $ true `notIn` [false, null_]
113+TRUE NOT IN (FALSE, NULL)
114+-}
115+notIn
116+ :: Expression outer commons grp schemas params from ty -- ^ expression
117+ -> [Expression outer commons grp schemas params from ty]
118+ -> Condition outer commons grp schemas params from
119+expr `notIn` exprs = UnsafeExpression $ renderSQL expr <+> "NOT IN"
120+ <+> parenthesized (commaSeparated (renderSQL <$> exprs))
squeal-postgresql/src/Squeal/PostgreSQL/Expression/Text.hsnew file+64
@@ -0,0 +1,64 @@
1+{-|
2+Module: Squeal.PostgreSQL.Expression.Text
3+Description: Text expressions
4+Copyright: (c) Eitan Chatav, 2019
5+Maintainer: eitan@morphism.tech
6+Stability: experimental
7+
8+String functions and operators
9+-}
10+
11+{-# LANGUAGE
12+ DataKinds
13+ , OverloadedStrings
14+ , TypeOperators
15+#-}
16+
17+module Squeal.PostgreSQL.Expression.Text
18+ ( lower
19+ , upper
20+ , charLength
21+ , like
22+ , ilike
23+ ) where
24+
25+import Squeal.PostgreSQL.Expression
26+import Squeal.PostgreSQL.Schema
27+
28+-- $setup
29+-- >>> import Squeal.PostgreSQL
30+
31+-- | >>> printSQL $ lower "ARRRGGG"
32+-- lower(E'ARRRGGG')
33+lower :: null 'PGtext --> null 'PGtext
34+lower = unsafeFunction "lower"
35+
36+-- | >>> printSQL $ upper "eeee"
37+-- upper(E'eeee')
38+upper :: null 'PGtext --> null 'PGtext
39+upper = unsafeFunction "upper"
40+
41+-- | >>> printSQL $ charLength "four"
42+-- char_length(E'four')
43+charLength :: null 'PGtext --> null 'PGint4
44+charLength = unsafeFunction "char_length"
45+
46+-- | The `like` expression returns true if the @string@ matches
47+-- the supplied @pattern@. If @pattern@ does not contain percent signs
48+-- or underscores, then the pattern only represents the string itself;
49+-- in that case `like` acts like the equals operator. An underscore (_)
50+-- in pattern stands for (matches) any single character; a percent sign (%)
51+-- matches any sequence of zero or more characters.
52+--
53+-- >>> printSQL $ "abc" `like` "a%"
54+-- (E'abc' LIKE E'a%')
55+like :: Operator (null 'PGtext) (null 'PGtext) ('Null 'PGbool)
56+like = unsafeBinaryOp "LIKE"
57+
58+-- | The key word ILIKE can be used instead of LIKE to make the
59+-- match case-insensitive according to the active locale.
60+--
61+-- >>> printSQL $ "abc" `ilike` "a%"
62+-- (E'abc' ILIKE E'a%')
63+ilike :: Operator (null 'PGtext) (null 'PGtext) ('Null 'PGbool)
64+ilike = unsafeBinaryOp "ILIKE"
squeal-postgresql/src/Squeal/PostgreSQL/Expression/TextSearch.hsnew file+157
@@ -0,0 +1,157 @@
1+{-|
2+Module: Squeal.PostgreSQL.Expression.TextSearch
3+Description: Text search expressions
4+Copyright: (c) Eitan Chatav, 2019
5+Maintainer: eitan@morphism.tech
6+Stability: experimental
7+
8+Text search functions and operators
9+-}
10+
11+{-# LANGUAGE
12+ DataKinds
13+ , OverloadedStrings
14+ , TypeOperators
15+#-}
16+
17+module Squeal.PostgreSQL.Expression.TextSearch
18+ ( (@@)
19+ , (.&)
20+ , (.|)
21+ , (.!)
22+ , (<->)
23+ , arrayToTSvector
24+ , tsvectorLength
25+ , numnode
26+ , plainToTSquery
27+ , phraseToTSquery
28+ , websearchToTSquery
29+ , queryTree
30+ , toTSquery
31+ , toTSvector
32+ , setWeight
33+ , strip
34+ , jsonToTSvector
35+ , jsonbToTSvector
36+ , tsDelete
37+ , tsFilter
38+ , tsHeadline
39+ ) where
40+
41+import Squeal.PostgreSQL.Expression
42+import Squeal.PostgreSQL.List
43+import Squeal.PostgreSQL.Schema
44+
45+-- | `Squeal.PostgreSQL.Expression.Type.tsvector` matches tsquery ?
46+(@@) :: Operator (null 'PGtsvector) (null 'PGtsquery) ('Null 'PGbool)
47+(@@) = unsafeBinaryOp "@@"
48+
49+-- | AND `Squeal.PostgreSQL.Expression.Type.tsquery`s together
50+(.&) :: Operator (null 'PGtsquery) (null 'PGtsquery) (null 'PGtsquery)
51+(.&) = unsafeBinaryOp "&&"
52+
53+-- | OR `Squeal.PostgreSQL.Expression.Type.tsquery`s together
54+(.|) :: Operator (null 'PGtsquery) (null 'PGtsquery) (null 'PGtsquery)
55+(.|) = unsafeBinaryOp "||"
56+
57+-- | negate a `Squeal.PostgreSQL.Expression.Type.tsquery`
58+(.!) :: null 'PGtsquery --> null 'PGtsquery
59+(.!) = unsafeLeftOp "!!"
60+
61+-- | `Squeal.PostgreSQL.Expression.Type.tsquery` followed by
62+-- `Squeal.PostgreSQL.Expression.Type.tsquery`
63+(<->) :: Operator (null 'PGtsquery) (null 'PGtsquery) (null 'PGtsquery)
64+(<->) = unsafeBinaryOp "<->"
65+
66+-- | convert array of lexemes to `Squeal.PostgreSQL.Expression.Type.tsvector`
67+arrayToTSvector
68+ :: null ('PGvararray ('NotNull 'PGtext))
69+ --> null 'PGtsvector
70+arrayToTSvector = unsafeFunction "array_to_tsvector"
71+
72+-- | number of lexemes in `Squeal.PostgreSQL.Expression.Type.tsvector`
73+tsvectorLength :: null 'PGtsvector --> null 'PGint4
74+tsvectorLength = unsafeFunction "length"
75+
76+-- | number of lexemes plus operators in `Squeal.PostgreSQL.Expression.Type.tsquery`
77+numnode :: null 'PGtsquery --> null 'PGint4
78+numnode = unsafeFunction "numnode"
79+
80+-- | produce `Squeal.PostgreSQL.Expression.Type.tsquery` ignoring punctuation
81+plainToTSquery :: null 'PGtext --> null 'PGtsquery
82+plainToTSquery = unsafeFunction "plainto_tsquery"
83+
84+-- | produce `Squeal.PostgreSQL.Expression.Type.tsquery` that searches for a phrase,
85+-- ignoring punctuation
86+phraseToTSquery :: null 'PGtext --> null 'PGtsquery
87+phraseToTSquery = unsafeFunction "phraseto_tsquery"
88+
89+-- | produce `Squeal.PostgreSQL.Expression.Type.tsquery` from a web search style query
90+websearchToTSquery :: null 'PGtext --> null 'PGtsquery
91+websearchToTSquery = unsafeFunction "websearch_to_tsquery"
92+
93+-- | get indexable part of a `Squeal.PostgreSQL.Expression.Type.tsquery`
94+queryTree :: null 'PGtsquery --> null 'PGtext
95+queryTree = unsafeFunction "query_tree"
96+
97+-- | normalize words and convert to `Squeal.PostgreSQL.Expression.Type.tsquery`
98+toTSquery :: null 'PGtext --> null 'PGtsquery
99+toTSquery = unsafeFunction "to_tsquery"
100+
101+-- | reduce document text to `Squeal.PostgreSQL.Expression.Type.tsvector`
102+toTSvector
103+ :: ty `In` '[ 'PGtext, 'PGjson, 'PGjsonb]
104+ => null ty --> null 'PGtsvector
105+toTSvector = unsafeFunction "to_tsvector"
106+
107+-- | assign weight to each element of `Squeal.PostgreSQL.Expression.Type.tsvector`
108+setWeight :: '[null 'PGtsvector, null ('PGchar 1)] ---> null 'PGtsvector
109+setWeight = unsafeFunctionN "set_weight"
110+
111+-- | remove positions and weights from `Squeal.PostgreSQL.Expression.Type.tsvector`
112+strip :: null 'PGtsvector --> null 'PGtsvector
113+strip = unsafeFunction "strip"
114+
115+-- | @jsonToTSvector (document *: filter)@
116+-- reduce each value in the document, specified by filter to a `Squeal.PostgreSQL.Expression.Type.tsvector`,
117+-- and then concatenate those in document order to produce a single `Squeal.PostgreSQL.Expression.Type.tsvector`.
118+-- filter is a `Squeal.PostgreSQL.Expression.Type.json` array, that enumerates what kind of elements
119+-- need to be included into the resulting `Squeal.PostgreSQL.Expression.Type.tsvector`.
120+-- Possible values for filter are "string" (to include all string values),
121+-- "numeric" (to include all numeric values in the string format),
122+-- "boolean" (to include all Boolean values in the string format "true"/"false"),
123+-- "key" (to include all keys) or "all" (to include all above).
124+-- These values can be combined together to include, e.g. all string and numeric values.
125+jsonToTSvector :: '[null 'PGjson, null 'PGjson] ---> null 'PGtsvector
126+jsonToTSvector = unsafeFunctionN "json_to_tsvector"
127+
128+-- | @jsonbToTSvector (document *: filter)@
129+-- reduce each value in the document, specified by filter to a `Squeal.PostgreSQL.Expression.Type.tsvector`,
130+-- and then concatenate those in document order to produce a single `Squeal.PostgreSQL.Expression.Type.tsvector`.
131+-- filter is a `Squeal.PostgreSQL.Expression.Type.jsonb` array, that enumerates what kind of elements
132+-- need to be included into the resulting `Squeal.PostgreSQL.Expression.Type.tsvector`.
133+-- Possible values for filter are "string" (to include all string values),
134+-- "numeric" (to include all numeric values in the string format),
135+-- "boolean" (to include all Boolean values in the string format "true"/"false"),
136+-- "key" (to include all keys) or "all" (to include all above).
137+-- These values can be combined together to include, e.g. all string and numeric values.
138+jsonbToTSvector :: '[null 'PGjsonb, null 'PGjsonb] ---> null 'PGtsvector
139+jsonbToTSvector = unsafeFunctionN "jsonb_to_tsvector"
140+
141+-- | remove given lexeme from `Squeal.PostgreSQL.Expression.Type.tsvector`
142+tsDelete ::
143+ '[null 'PGtsvector, null ('PGvararray ('NotNull 'PGtext))]
144+ ---> null 'PGtsvector
145+tsDelete = unsafeFunctionN "ts_delete"
146+
147+-- | select only elements with given weights from `Squeal.PostgreSQL.Expression.Type.tsvector`
148+tsFilter ::
149+ '[null 'PGtsvector, null ('PGvararray ('NotNull ('PGchar 1)))]
150+ ---> null 'PGtsvector
151+tsFilter = unsafeFunctionN "ts_filter"
152+
153+-- | display a `Squeal.PostgreSQL.Expression.Type.tsquery` match
154+tsHeadline
155+ :: document `In` '[ 'PGtext, 'PGjson, 'PGjsonb]
156+ => '[null document, null 'PGtsquery] ---> null 'PGtext
157+tsHeadline = unsafeFunctionN "ts_headline"
squeal-postgresql/src/Squeal/PostgreSQL/Expression/Time.hsnew file+192
@@ -0,0 +1,192 @@
1+{-|
2+Module: Squeal.PostgreSQL.Expression.Time
3+Description: Date/Time expressions
4+Copyright: (c) Eitan Chatav, 2019
5+Maintainer: eitan@morphism.tech
6+Stability: experimental
7+
8+Date/Time functions and operators
9+-}
10+
11+{-# LANGUAGE
12+ DataKinds
13+ , DeriveGeneric
14+ , FunctionalDependencies
15+ , LambdaCase
16+ , MultiParamTypeClasses
17+ , OverloadedStrings
18+ , PolyKinds
19+ , RankNTypes
20+ , TypeOperators
21+#-}
22+
23+module Squeal.PostgreSQL.Expression.Time
24+ ( TimeOp (..)
25+ , currentDate
26+ , currentTime
27+ , currentTimestamp
28+ , localTime
29+ , localTimestamp
30+ , now
31+ , makeDate
32+ , makeTime
33+ , makeTimestamp
34+ , makeTimestamptz
35+ , interval_
36+ , TimeUnit (..)
37+ ) where
38+
39+import Data.String
40+
41+import qualified GHC.Generics as GHC
42+import qualified Generics.SOP as SOP
43+
44+import Squeal.PostgreSQL.Expression
45+import Squeal.PostgreSQL.Render
46+import Squeal.PostgreSQL.Schema
47+
48+-- $setup
49+-- >>> import Squeal.PostgreSQL
50+
51+-- | >>> printSQL currentDate
52+-- CURRENT_DATE
53+currentDate :: Expr (null 'PGdate)
54+currentDate = UnsafeExpression "CURRENT_DATE"
55+
56+-- | >>> printSQL currentTime
57+-- CURRENT_TIME
58+currentTime :: Expr (null 'PGtimetz)
59+currentTime = UnsafeExpression "CURRENT_TIME"
60+
61+-- | >>> printSQL currentTimestamp
62+-- CURRENT_TIMESTAMP
63+currentTimestamp :: Expr (null 'PGtimestamptz)
64+currentTimestamp = UnsafeExpression "CURRENT_TIMESTAMP"
65+
66+-- | >>> printSQL localTime
67+-- LOCALTIME
68+localTime :: Expr (null 'PGtime)
69+localTime = UnsafeExpression "LOCALTIME"
70+
71+-- | >>> printSQL localTimestamp
72+-- LOCALTIMESTAMP
73+localTimestamp :: Expr (null 'PGtimestamp)
74+localTimestamp = UnsafeExpression "LOCALTIMESTAMP"
75+
76+-- | Current date and time (equivalent to `currentTimestamp`)
77+--
78+-- >>> printSQL now
79+-- now()
80+now :: Expr (null 'PGtimestamptz)
81+now = UnsafeExpression "now()"
82+
83+{-|
84+Create date from year, month and day fields
85+
86+>>> printSQL (makeDate (1984 :* 7 *: 3))
87+make_date(1984, 7, 3)
88+-}
89+makeDate :: '[ null 'PGint4, null 'PGint4, null 'PGint4 ] ---> null 'PGdate
90+makeDate = unsafeFunctionN "make_date"
91+
92+{-|
93+Create time from hour, minute and seconds fields
94+
95+>>> printSQL (makeTime (8 :* 15 *: 23.5))
96+make_time(8, 15, 23.5)
97+-}
98+makeTime :: '[ null 'PGint4, null 'PGint4, null 'PGfloat8 ] ---> null 'PGtime
99+makeTime = unsafeFunctionN "make_time"
100+
101+{-|
102+Create timestamp from year, month, day, hour, minute and seconds fields
103+
104+>>> printSQL (makeTimestamp (2013 :* 7 :* 15 :* 8 :* 15 *: 23.5))
105+make_timestamp(2013, 7, 15, 8, 15, 23.5)
106+-}
107+makeTimestamp ::
108+ '[ null 'PGint4, null 'PGint4, null 'PGint4
109+ , null 'PGint4, null 'PGint4, null 'PGfloat8 ] ---> null 'PGtimestamp
110+makeTimestamp = unsafeFunctionN "make_timestamp"
111+
112+{-|
113+Create timestamp with time zone from
114+year, month, day, hour, minute and seconds fields;
115+the current time zone is used
116+
117+>>> printSQL (makeTimestamptz (2013 :* 7 :* 15 :* 8 :* 15 *: 23.5))
118+make_timestamptz(2013, 7, 15, 8, 15, 23.5)
119+-}
120+makeTimestamptz ::
121+ '[ null 'PGint4, null 'PGint4, null 'PGint4
122+ , null 'PGint4, null 'PGint4, null 'PGfloat8 ] ---> null 'PGtimestamptz
123+makeTimestamptz = unsafeFunctionN "make_timestamptz"
124+
125+{-|
126+Affine space operations on time types.
127+-}
128+class TimeOp time diff | time -> diff where
129+ {-|
130+ >>> printSQL (makeDate (1984 :* 7 *: 3) !+ 365)
131+ (make_date(1984, 7, 3) + 365)
132+ -}
133+ (!+) :: Operator (null time) (null diff) (null time)
134+ (!+) = unsafeBinaryOp "+"
135+ {-|
136+ >>> printSQL (365 +! makeDate (1984 :* 7 *: 3))
137+ (365 + make_date(1984, 7, 3))
138+ -}
139+ (+!) :: Operator (null diff) (null time) (null time)
140+ (+!) = unsafeBinaryOp "+"
141+ {-|
142+ >>> printSQL (makeDate (1984 :* 7 *: 3) !- 365)
143+ (make_date(1984, 7, 3) - 365)
144+ -}
145+ (!-) :: Operator (null time) (null diff) (null time)
146+ (!-) = unsafeBinaryOp "-"
147+ {-|
148+ >>> printSQL (makeDate (1984 :* 7 *: 3) !-! currentDate)
149+ (make_date(1984, 7, 3) - CURRENT_DATE)
150+ -}
151+ (!-!) :: Operator (null time) (null time) (null diff)
152+ (!-!) = unsafeBinaryOp "-"
153+instance TimeOp 'PGtimestamp 'PGinterval
154+instance TimeOp 'PGtimestamptz 'PGinterval
155+instance TimeOp 'PGtime 'PGinterval
156+instance TimeOp 'PGtimetz 'PGinterval
157+instance TimeOp 'PGinterval 'PGinterval
158+instance TimeOp 'PGdate 'PGint4
159+infixl 6 !+
160+infixl 6 +!
161+infixl 6 !-
162+infixl 6 !-!
163+
164+-- | A `TimeUnit` to use in `interval_` construction.
165+data TimeUnit
166+ = Years | Months | Weeks | Days
167+ | Hours | Minutes | Seconds
168+ | Microseconds | Milliseconds
169+ | Decades | Centuries | Millennia
170+ deriving (Eq, Ord, Show, Read, Enum, GHC.Generic)
171+instance SOP.Generic TimeUnit
172+instance SOP.HasDatatypeInfo TimeUnit
173+instance RenderSQL TimeUnit where
174+ renderSQL = \case
175+ Years -> "years"
176+ Months -> "months"
177+ Weeks -> "weeks"
178+ Days -> "days"
179+ Hours -> "hours"
180+ Minutes -> "minutes"
181+ Seconds -> "seconds"
182+ Microseconds -> "microseconds"
183+ Milliseconds -> "milliseconds"
184+ Decades -> "decades"
185+ Centuries -> "centuries"
186+ Millennia -> "millennia"
187+
188+-- | >>> printSQL $ interval_ 7 Days
189+-- (INTERVAL '7.0 days')
190+interval_ :: Double -> TimeUnit -> Expr (null 'PGinterval)
191+interval_ num unit = UnsafeExpression . parenthesized $ "INTERVAL" <+>
192+ "'" <> fromString (show num) <+> renderSQL unit <> "'"
squeal-postgresql/src/Squeal/PostgreSQL/Expression/Type.hsnew file+446
@@ -0,0 +1,446 @@
1+{-|
2+Module: Squeal.PostgreSQL.Expression
3+Description: Type expressions
4+Copyright: (c) Eitan Chatav, 2019
5+Maintainer: eitan@morphism.tech
6+Stability: experimental
7+
8+Type expressions.
9+-}
10+
11+{-# LANGUAGE
12+ AllowAmbiguousTypes
13+ , DataKinds
14+ , DeriveGeneric
15+ , FlexibleContexts
16+ , FlexibleInstances
17+ , GADTs
18+ , GeneralizedNewtypeDeriving
19+ , KindSignatures
20+ , MultiParamTypeClasses
21+ , OverloadedStrings
22+ , RankNTypes
23+ , ScopedTypeVariables
24+ , TypeApplications
25+ , TypeOperators
26+ , UndecidableInstances
27+#-}
28+
29+module Squeal.PostgreSQL.Expression.Type
30+ ( -- * type casting
31+ cast
32+ , astype
33+ , inferredtype
34+ -- * type expressions
35+ , TypeExpression (..)
36+ , typedef
37+ , typetable
38+ , typeview
39+ , bool
40+ , int2
41+ , smallint
42+ , int4
43+ , int
44+ , integer
45+ , int8
46+ , bigint
47+ , numeric
48+ , float4
49+ , real
50+ , float8
51+ , doublePrecision
52+ , money
53+ , text
54+ , char
55+ , character
56+ , varchar
57+ , characterVarying
58+ , bytea
59+ , timestamp
60+ , timestampWithTimeZone
61+ , timestamptz
62+ , date
63+ , time
64+ , timeWithTimeZone
65+ , timetz
66+ , interval
67+ , uuid
68+ , inet
69+ , json
70+ , jsonb
71+ , vararray
72+ , fixarray
73+ , tsvector
74+ , tsquery
75+ , oid
76+ , int4range
77+ , int8range
78+ , numrange
79+ , tsrange
80+ , tstzrange
81+ , daterange
82+ -- * column type definitions
83+ , ColumnTypeExpression (..)
84+ , nullable
85+ , notNullable
86+ , default_
87+ , serial2
88+ , smallserial
89+ , serial4
90+ , serial
91+ , serial8
92+ , bigserial
93+ , hask
94+ -- * type inference
95+ , PGTyped (..)
96+ , PGNullityTyped (..)
97+ , FieldTyped (..)
98+ ) where
99+
100+import Control.DeepSeq
101+import Data.ByteString
102+import Data.String
103+import GHC.TypeLits
104+
105+import qualified Data.ByteString as ByteString
106+import qualified GHC.Generics as GHC
107+import qualified Generics.SOP as SOP
108+
109+import Squeal.PostgreSQL.Alias
110+import Squeal.PostgreSQL.Expression
111+import Squeal.PostgreSQL.PG
112+import Squeal.PostgreSQL.Render
113+import Squeal.PostgreSQL.Schema
114+
115+-- $setup
116+-- >>> import Squeal.PostgreSQL
117+
118+-- When a `cast` is applied to an `Expression` of a known type, it
119+-- represents a run-time type conversion. The cast will succeed only if a
120+-- suitable type conversion operation has been defined.
121+--
122+-- | >>> printSQL $ true & cast int4
123+-- (TRUE :: int4)
124+cast
125+ :: TypeExpression schemas ty1
126+ -- ^ type to cast as
127+ -> Expression outer commons grp schemas params from ty0
128+ -- ^ value to convert
129+ -> Expression outer commons grp schemas params from ty1
130+cast ty x = UnsafeExpression $ parenthesized $
131+ renderSQL x <+> "::" <+> renderSQL ty
132+
133+-- | A safe version of `cast` which just matches a value with its type.
134+--
135+-- >>> printSQL (1 & astype int)
136+-- (1 :: int)
137+astype
138+ :: TypeExpression schemas ty
139+ -- ^ type to specify as
140+ -> Expression outer commons grp schemas params from ty
141+ -- ^ value
142+ -> Expression outer commons grp schemas params from ty
143+astype = cast
144+
145+-- | `inferredtype` will add a type annotation to an `Expression`
146+-- which can be useful for fixing the storage type of a value.
147+--
148+-- >>> printSQL (inferredtype true)
149+-- (TRUE :: bool)
150+inferredtype
151+ :: PGTyped schemas ty
152+ => Expression outer common grp schemas params from ty
153+ -- ^ value
154+ -> Expression outer common grp schemas params from ty
155+inferredtype = astype pgtype
156+
157+{-----------------------------------------
158+type expressions
159+-----------------------------------------}
160+
161+-- | `TypeExpression`s are used in `cast`s and
162+-- `Squeal.PostgreSQL.Definition.createTable` commands.
163+newtype TypeExpression (schemas :: SchemasType) (ty :: NullityType)
164+ = UnsafeTypeExpression { renderTypeExpression :: ByteString }
165+ deriving (GHC.Generic,Show,Eq,Ord,NFData)
166+instance RenderSQL (TypeExpression schemas ty) where
167+ renderSQL = renderTypeExpression
168+
169+-- | The enum or composite type in a `Typedef` can be expressed by its alias.
170+typedef
171+ :: (Has sch schemas schema, Has td schema ('Typedef ty))
172+ => QualifiedAlias sch td
173+ -- ^ type alias
174+ -> TypeExpression schemas (null ty)
175+typedef = UnsafeTypeExpression . renderSQL
176+
177+-- | The composite type corresponding to a `Table` definition can be expressed
178+-- by its alias.
179+typetable
180+ :: (Has sch schemas schema, Has tab schema ('Table table))
181+ => QualifiedAlias sch tab
182+ -- ^ table alias
183+ -> TypeExpression schemas (null ('PGcomposite (TableToRow table)))
184+typetable = UnsafeTypeExpression . renderSQL
185+
186+-- | The composite type corresponding to a `View` definition can be expressed
187+-- by its alias.
188+typeview
189+ :: (Has sch schemas schema, Has vw schema ('View view))
190+ => QualifiedAlias sch vw
191+ -- ^ view alias
192+ -> TypeExpression schemas (null ('PGcomposite view))
193+typeview = UnsafeTypeExpression . renderSQL
194+
195+-- | logical Boolean (true/false)
196+bool :: TypeExpression schemas (null 'PGbool)
197+bool = UnsafeTypeExpression "bool"
198+-- | signed two-byte integer
199+int2, smallint :: TypeExpression schemas (null 'PGint2)
200+int2 = UnsafeTypeExpression "int2"
201+smallint = UnsafeTypeExpression "smallint"
202+-- | signed four-byte integer
203+int4, int, integer :: TypeExpression schemas (null 'PGint4)
204+int4 = UnsafeTypeExpression "int4"
205+int = UnsafeTypeExpression "int"
206+integer = UnsafeTypeExpression "integer"
207+-- | signed eight-byte integer
208+int8, bigint :: TypeExpression schemas (null 'PGint8)
209+int8 = UnsafeTypeExpression "int8"
210+bigint = UnsafeTypeExpression "bigint"
211+-- | arbitrary precision numeric type
212+numeric :: TypeExpression schemas (null 'PGnumeric)
213+numeric = UnsafeTypeExpression "numeric"
214+-- | single precision floating-point number (4 bytes)
215+float4, real :: TypeExpression schemas (null 'PGfloat4)
216+float4 = UnsafeTypeExpression "float4"
217+real = UnsafeTypeExpression "real"
218+-- | double precision floating-point number (8 bytes)
219+float8, doublePrecision :: TypeExpression schemas (null 'PGfloat8)
220+float8 = UnsafeTypeExpression "float8"
221+doublePrecision = UnsafeTypeExpression "double precision"
222+-- | currency amount
223+money :: TypeExpression schema (null 'PGmoney)
224+money = UnsafeTypeExpression "money"
225+-- | variable-length character string
226+text :: TypeExpression schemas (null 'PGtext)
227+text = UnsafeTypeExpression "text"
228+-- | fixed-length character string
229+char, character
230+ :: forall n schemas null. (KnownNat n, 1 <= n)
231+ => TypeExpression schemas (null ('PGchar n))
232+char = UnsafeTypeExpression $ "char(" <> renderNat @n <> ")"
233+character = UnsafeTypeExpression $ "character(" <> renderNat @n <> ")"
234+-- | variable-length character string
235+varchar, characterVarying
236+ :: forall n schemas null. (KnownNat n, 1 <= n)
237+ => TypeExpression schemas (null ('PGvarchar n))
238+varchar = UnsafeTypeExpression $ "varchar(" <> renderNat @n <> ")"
239+characterVarying = UnsafeTypeExpression $
240+ "character varying(" <> renderNat @n <> ")"
241+-- | binary data ("byte array")
242+bytea :: TypeExpression schemas (null 'PGbytea)
243+bytea = UnsafeTypeExpression "bytea"
244+-- | date and time (no time zone)
245+timestamp :: TypeExpression schemas (null 'PGtimestamp)
246+timestamp = UnsafeTypeExpression "timestamp"
247+-- | date and time, including time zone
248+timestampWithTimeZone, timestamptz :: TypeExpression schemas (null 'PGtimestamptz)
249+timestampWithTimeZone = UnsafeTypeExpression "timestamp with time zone"
250+timestamptz = UnsafeTypeExpression "timestamptz"
251+-- | calendar date (year, month, day)
252+date :: TypeExpression schemas (null 'PGdate)
253+date = UnsafeTypeExpression "date"
254+-- | time of day (no time zone)
255+time :: TypeExpression schemas (null 'PGtime)
256+time = UnsafeTypeExpression "time"
257+-- | time of day, including time zone
258+timeWithTimeZone, timetz :: TypeExpression schemas (null 'PGtimetz)
259+timeWithTimeZone = UnsafeTypeExpression "time with time zone"
260+timetz = UnsafeTypeExpression "timetz"
261+-- | time span
262+interval :: TypeExpression schemas (null 'PGinterval)
263+interval = UnsafeTypeExpression "interval"
264+-- | universally unique identifier
265+uuid :: TypeExpression schemas (null 'PGuuid)
266+uuid = UnsafeTypeExpression "uuid"
267+-- | IPv4 or IPv6 host address
268+inet :: TypeExpression schemas (null 'PGinet)
269+inet = UnsafeTypeExpression "inet"
270+-- | textual JSON data
271+json :: TypeExpression schemas (null 'PGjson)
272+json = UnsafeTypeExpression "json"
273+-- | binary JSON data, decomposed
274+jsonb :: TypeExpression schemas (null 'PGjsonb)
275+jsonb = UnsafeTypeExpression "jsonb"
276+-- | variable length array
277+vararray
278+ :: TypeExpression schemas pg
279+ -> TypeExpression schemas (null ('PGvararray pg))
280+vararray ty = UnsafeTypeExpression $ renderSQL ty <> "[]"
281+-- | fixed length array
282+--
283+-- >>> renderSQL (fixarray @'[2] json)
284+-- "json[2]"
285+fixarray
286+ :: forall dims schemas null pg. SOP.All KnownNat dims
287+ => TypeExpression schemas pg
288+ -> TypeExpression schemas (null ('PGfixarray dims pg))
289+fixarray ty = UnsafeTypeExpression $
290+ renderSQL ty <> renderDims @dims
291+ where
292+ renderDims :: forall ns. SOP.All KnownNat ns => ByteString
293+ renderDims =
294+ ("[" <>)
295+ . (<> "]")
296+ . ByteString.intercalate "]["
297+ . SOP.hcollapse
298+ $ SOP.hcmap (SOP.Proxy @KnownNat)
299+ (K . fromString . show . natVal)
300+ (SOP.hpure SOP.Proxy :: SOP.NP SOP.Proxy ns)
301+-- | text search query
302+tsvector :: TypeExpression schemas (null 'PGtsvector)
303+tsvector = UnsafeTypeExpression "tsvector"
304+-- | text search document
305+tsquery :: TypeExpression schemas (null 'PGtsquery)
306+tsquery = UnsafeTypeExpression "tsquery"
307+-- | Object identifiers (OIDs) are used internally by PostgreSQL
308+-- as primary keys for various system tables.
309+oid :: TypeExpression schemas (null 'PGoid)
310+oid = UnsafeTypeExpression "oid"
311+-- | Range of integer
312+int4range :: TypeExpression schemas (null ('PGrange 'PGint4))
313+int4range = UnsafeTypeExpression "int4range"
314+-- | Range of bigint
315+int8range :: TypeExpression schemas (null ('PGrange 'PGint8))
316+int8range = UnsafeTypeExpression "int8range"
317+-- | Range of numeric
318+numrange :: TypeExpression schemas (null ('PGrange 'PGnumeric))
319+numrange = UnsafeTypeExpression "numrange"
320+-- | Range of timestamp without time zone
321+tsrange :: TypeExpression schemas (null ('PGrange 'PGtimestamp))
322+tsrange = UnsafeTypeExpression "tsrange"
323+-- | Range of timestamp with time zone
324+tstzrange :: TypeExpression schemas (null ('PGrange 'PGtimestamptz))
325+tstzrange = UnsafeTypeExpression "tstzrange"
326+-- | Range of date
327+daterange :: TypeExpression schemas (null ('PGrange 'PGdate))
328+daterange = UnsafeTypeExpression "daterange"
329+
330+-- | `pgtype` is a demoted version of a `PGType`
331+class PGTyped schemas (ty :: NullityType) where
332+ pgtype :: TypeExpression schemas ty
333+instance PGTyped schemas (null 'PGbool) where pgtype = bool
334+instance PGTyped schemas (null 'PGint2) where pgtype = int2
335+instance PGTyped schemas (null 'PGint4) where pgtype = int4
336+instance PGTyped schemas (null 'PGint8) where pgtype = int8
337+instance PGTyped schemas (null 'PGnumeric) where pgtype = numeric
338+instance PGTyped schemas (null 'PGfloat4) where pgtype = float4
339+instance PGTyped schemas (null 'PGfloat8) where pgtype = float8
340+instance PGTyped schemas (null 'PGmoney) where pgtype = money
341+instance PGTyped schemas (null 'PGtext) where pgtype = text
342+instance (KnownNat n, 1 <= n)
343+ => PGTyped schemas (null ('PGchar n)) where pgtype = char @n
344+instance (KnownNat n, 1 <= n)
345+ => PGTyped schemas (null ('PGvarchar n)) where pgtype = varchar @n
346+instance PGTyped schemas (null 'PGbytea) where pgtype = bytea
347+instance PGTyped schemas (null 'PGtimestamp) where pgtype = timestamp
348+instance PGTyped schemas (null 'PGtimestamptz) where pgtype = timestampWithTimeZone
349+instance PGTyped schemas (null 'PGdate) where pgtype = date
350+instance PGTyped schemas (null 'PGtime) where pgtype = time
351+instance PGTyped schemas (null 'PGtimetz) where pgtype = timeWithTimeZone
352+instance PGTyped schemas (null 'PGinterval) where pgtype = interval
353+instance PGTyped schemas (null 'PGuuid) where pgtype = uuid
354+instance PGTyped schemas (null 'PGjson) where pgtype = json
355+instance PGTyped schemas (null 'PGjsonb) where pgtype = jsonb
356+instance PGTyped schemas ty
357+ => PGTyped schemas (null ('PGvararray ty)) where
358+ pgtype = vararray (pgtype @schemas @ty)
359+instance (SOP.All KnownNat dims, PGTyped schemas ty)
360+ => PGTyped schemas (null ('PGfixarray dims ty)) where
361+ pgtype = fixarray @dims (pgtype @schemas @ty)
362+instance PGTyped schemas (null 'PGtsvector) where pgtype = tsvector
363+instance PGTyped schemas (null 'PGtsquery) where pgtype = tsquery
364+instance PGTyped schemas (null 'PGoid) where pgtype = oid
365+instance PGTyped schemas (null ('PGrange 'PGint4)) where pgtype = int4range
366+instance PGTyped schemas (null ('PGrange 'PGint8)) where pgtype = int8range
367+instance PGTyped schemas (null ('PGrange 'PGnumeric)) where pgtype = numrange
368+instance PGTyped schemas (null ('PGrange 'PGtimestamp)) where pgtype = tsrange
369+instance PGTyped schemas (null ('PGrange 'PGtimestamptz)) where pgtype = tstzrange
370+instance PGTyped schemas (null ('PGrange 'PGdate)) where pgtype = daterange
371+
372+-- | Lift `PGTyped` to a field
373+class FieldTyped schemas ty where
374+ fieldtype :: Aliased (TypeExpression schemas) ty
375+instance (KnownSymbol alias, PGTyped schemas ty)
376+ => FieldTyped schemas (alias ::: ty) where
377+ fieldtype = pgtype `As` Alias
378+
379+-- | `ColumnTypeExpression`s are used in `createTable` commands.
380+newtype ColumnTypeExpression (schemas :: SchemasType) (ty :: ColumnType)
381+ = UnsafeColumnTypeExpression { renderColumnTypeExpression :: ByteString }
382+ deriving (GHC.Generic,Show,Eq,Ord,NFData)
383+instance RenderSQL (ColumnTypeExpression schemas ty) where
384+ renderSQL = renderColumnTypeExpression
385+
386+-- | used in `createTable` commands as a column constraint to note that
387+-- @NULL@ may be present in a column
388+nullable
389+ :: TypeExpression schemas (nullity ty)
390+ -> ColumnTypeExpression schemas ('NoDef :=> 'Null ty)
391+nullable ty = UnsafeColumnTypeExpression $ renderSQL ty <+> "NULL"
392+
393+-- | used in `createTable` commands as a column constraint to ensure
394+-- @NULL@ is not present in a column
395+notNullable
396+ :: TypeExpression schemas (nullity ty)
397+ -> ColumnTypeExpression schemas ('NoDef :=> 'NotNull ty)
398+notNullable ty = UnsafeColumnTypeExpression $ renderSQL ty <+> "NOT NULL"
399+
400+-- | used in `createTable` commands as a column constraint to give a default
401+default_
402+ :: Expression '[] '[] 'Ungrouped schemas '[] '[] ty
403+ -> ColumnTypeExpression schemas ('NoDef :=> ty)
404+ -> ColumnTypeExpression schemas ('Def :=> ty)
405+default_ x ty = UnsafeColumnTypeExpression $
406+ renderSQL ty <+> "DEFAULT" <+> renderExpression x
407+
408+-- | not a true type, but merely a notational convenience for creating
409+-- unique identifier columns with type `PGint2`
410+serial2, smallserial
411+ :: ColumnTypeExpression schemas ('Def :=> 'NotNull 'PGint2)
412+serial2 = UnsafeColumnTypeExpression "serial2"
413+smallserial = UnsafeColumnTypeExpression "smallserial"
414+-- | not a true type, but merely a notational convenience for creating
415+-- unique identifier columns with type `PGint4`
416+serial4, serial
417+ :: ColumnTypeExpression schemas ('Def :=> 'NotNull 'PGint4)
418+serial4 = UnsafeColumnTypeExpression "serial4"
419+serial = UnsafeColumnTypeExpression "serial"
420+-- | not a true type, but merely a notational convenience for creating
421+-- unique identifier columns with type `PGint8`
422+serial8, bigserial
423+ :: ColumnTypeExpression schemas ('Def :=> 'NotNull 'PGint8)
424+serial8 = UnsafeColumnTypeExpression "serial8"
425+bigserial = UnsafeColumnTypeExpression "bigserial"
426+
427+-- | Like @PGTyped@ but also accounts for nullity.
428+class PGNullityTyped schemas (nullty :: NullityType) where
429+ pgNullityType :: ColumnTypeExpression schemas ('NoDef :=> nullty)
430+
431+instance PGTyped schemas ('Null ty) => PGNullityTyped schemas ('Null ty) where
432+ pgNullityType = nullable (pgtype @_ @('Null ty))
433+
434+instance PGTyped schemas ('NotNull ty) => PGNullityTyped schemas ('NotNull ty) where
435+ pgNullityType = notNullable (pgtype @_ @('NotNull ty))
436+
437+-- | Allow you to specify pg column types in relation to haskell types.
438+-- >>> printSQL $ hask @(Maybe String)
439+-- text NULL
440+--
441+-- >>> printSQL $ hask @Double
442+-- float8 NOT NULL
443+hask
444+ :: forall hask schemas. PGNullityTyped schemas (NullPG hask)
445+ => ColumnTypeExpression schemas ('NoDef :=> NullPG hask)
446+hask = pgNullityType
squeal-postgresql/src/Squeal/PostgreSQL/Expression/Window.hsnew file+284
@@ -0,0 +1,284 @@
1+{-|
2+Module: Squeal.PostgreSQL.Expression.Window
3+Description: Window functions
4+Copyright: (c) Eitan Chatav, 2019
5+Maintainer: eitan@morphism.tech
6+Stability: experimental
7+
8+Window functions and definitions
9+-}
10+
11+{-# LANGUAGE
12+ DataKinds
13+ , DeriveGeneric
14+ , FlexibleContexts
15+ , FlexibleInstances
16+ , GADTs
17+ , GeneralizedNewtypeDeriving
18+ , LambdaCase
19+ , MultiParamTypeClasses
20+ , OverloadedStrings
21+ , RankNTypes
22+ , KindSignatures
23+#-}
24+
25+module Squeal.PostgreSQL.Expression.Window
26+ ( -- * functions
27+ partitionBy
28+ , rank
29+ , rowNumber
30+ , denseRank
31+ , percentRank
32+ , cumeDist
33+ , ntile
34+ , lag
35+ , lead
36+ , firstValue
37+ , lastValue
38+ , nthValue
39+ , unsafeWindowFunction1
40+ , unsafeWindowFunctionN
41+ -- * types
42+ , WindowFunction (..)
43+ , WindowDefinition (..)
44+ , WinFun0
45+ , WinFun1
46+ , WinFunN
47+ ) where
48+
49+import Control.DeepSeq
50+import Data.ByteString
51+
52+import qualified GHC.Generics as GHC
53+import qualified Generics.SOP as SOP
54+
55+import Squeal.PostgreSQL.Alias
56+import Squeal.PostgreSQL.Expression
57+import Squeal.PostgreSQL.Expression.Aggregate
58+import Squeal.PostgreSQL.Expression.Sort
59+import Squeal.PostgreSQL.List
60+import Squeal.PostgreSQL.Render
61+import Squeal.PostgreSQL.Schema
62+
63+instance Aggregate
64+ (Expression outer commons grp schemas params from)
65+ (NP (Expression outer commons grp schemas params from))
66+ (WindowFunction outer commons grp schemas params from) where
67+ countStar = UnsafeWindowFunction "count(*)"
68+ count = unsafeWindowFunction1 "count"
69+ sum_ = unsafeWindowFunction1 "sum"
70+ arrayAgg = unsafeWindowFunction1 "array_agg"
71+ jsonAgg = unsafeWindowFunction1 "json_agg"
72+ jsonbAgg = unsafeWindowFunction1 "jsonb_agg"
73+ bitAnd = unsafeWindowFunction1 "bit_and"
74+ bitOr = unsafeWindowFunction1 "bit_or"
75+ boolAnd = unsafeWindowFunction1 "bool_and"
76+ boolOr = unsafeWindowFunction1 "bool_or"
77+ every = unsafeWindowFunction1 "every"
78+ max_ = unsafeWindowFunction1 "max"
79+ min_ = unsafeWindowFunction1 "min"
80+ avg = unsafeWindowFunction1 "avg"
81+ corr = unsafeWindowFunctionN "corr"
82+ covarPop = unsafeWindowFunctionN "covar_pop"
83+ covarSamp = unsafeWindowFunctionN "covar_samp"
84+ regrAvgX = unsafeWindowFunctionN "regr_avgx"
85+ regrAvgY = unsafeWindowFunctionN "regr_avgy"
86+ regrCount = unsafeWindowFunctionN "regr_count"
87+ regrIntercept = unsafeWindowFunctionN "regr_intercept"
88+ regrR2 = unsafeWindowFunctionN "regr_r2"
89+ regrSlope = unsafeWindowFunctionN "regr_slope"
90+ regrSxx = unsafeWindowFunctionN "regr_sxx"
91+ regrSxy = unsafeWindowFunctionN "regr_sxy"
92+ regrSyy = unsafeWindowFunctionN "regr_syy"
93+ stddev = unsafeWindowFunction1 "stddev"
94+ stddevPop = unsafeWindowFunction1 "stddev_pop"
95+ stddevSamp = unsafeWindowFunction1 "stddev_samp"
96+ variance = unsafeWindowFunction1 "variance"
97+ varPop = unsafeWindowFunction1 "var_pop"
98+ varSamp = unsafeWindowFunction1 "var_samp"
99+
100+-- | A `WindowDefinition` is a set of table rows that are somehow related
101+-- to the current row
102+data WindowDefinition outer commons grp schemas params from where
103+ WindowDefinition
104+ :: SOP.SListI bys
105+ => NP (Expression outer commons grp schemas params from) bys
106+ -- ^ `partitionBy` clause
107+ -> [SortExpression outer commons grp schemas params from]
108+ -- ^ `Squeal.PostgreSQL.Expression.Sort.orderBy` clause
109+ -> WindowDefinition outer commons grp schemas params from
110+
111+instance OrderBy WindowDefinition where
112+ orderBy sortsR (WindowDefinition parts sortsL)
113+ = WindowDefinition parts (sortsL ++ sortsR)
114+
115+instance RenderSQL (WindowDefinition outer commons schemas from grp params) where
116+ renderSQL (WindowDefinition part ord) =
117+ renderPartitionByClause part <> renderOrderByClause ord
118+ where
119+ renderPartitionByClause = \case
120+ Nil -> ""
121+ parts -> "PARTITION" <+> "BY" <+> renderCommaSeparated renderExpression parts
122+ renderOrderByClause = \case
123+ [] -> ""
124+ srts -> " ORDER" <+> "BY"
125+ <+> commaSeparated (renderSQL <$> srts)
126+
127+{- |
128+The `partitionBy` clause within `Squeal.PostgreSQL.Query.Over` divides the rows into groups,
129+or partitions, that share the same values of the `partitionBy` `Expression`(s).
130+For each row, the window function is computed across the rows that fall into
131+the same partition as the current row.
132+-}
133+partitionBy
134+ :: SOP.SListI bys
135+ => NP (Expression outer commons grp schemas params from) bys -- ^ partitions
136+ -> WindowDefinition outer commons grp schemas params from
137+partitionBy bys = WindowDefinition bys []
138+
139+{- |
140+A window function performs a calculation across a set of table rows
141+that are somehow related to the current row. This is comparable to the type
142+of calculation that can be done with an aggregate function.
143+However, window functions do not cause rows to become grouped into a single
144+output row like non-window aggregate calls would.
145+Instead, the rows retain their separate identities.
146+Behind the scenes, the window function is able to access more than
147+just the current row of the query result.
148+-}
149+newtype WindowFunction
150+ (outer :: FromType)
151+ (commons :: FromType)
152+ (grp :: Grouping)
153+ (schemas :: SchemasType)
154+ (params :: [NullityType])
155+ (from :: FromType)
156+ (ty :: NullityType)
157+ = UnsafeWindowFunction { renderWindowFunction :: ByteString }
158+ deriving (GHC.Generic,Show,Eq,Ord,NFData)
159+
160+instance RenderSQL (WindowFunction outer commons grp schemas params from ty) where
161+ renderSQL = renderWindowFunction
162+
163+{- |
164+A @RankNType@ for window functions with no arguments.
165+-}
166+type WinFun0 x
167+ = forall outer commons grp schemas params from
168+ . WindowFunction outer commons grp schemas params from x
169+ -- ^ cannot reference aliases
170+
171+{- |
172+A @RankNType@ for window functions with 1 argument.
173+-}
174+type WinFun1 x y
175+ = forall outer commons grp schemas params from
176+ . Expression outer commons grp schemas params from x
177+ -- ^ input
178+ -> WindowFunction outer commons grp schemas params from y
179+ -- ^ output
180+
181+{- | A @RankNType@ for window functions with a fixed-length
182+list of heterogeneous arguments.
183+Use the `*:` operator to end your argument lists.
184+-}
185+type WinFunN xs y
186+ = forall outer commons grp schemas params from
187+ . NP (Expression outer commons grp schemas params from) xs
188+ -- ^ inputs
189+ -> WindowFunction outer commons grp schemas params from y
190+ -- ^ output
191+
192+-- | escape hatch for defining window functions
193+unsafeWindowFunction1 :: ByteString -> WinFun1 x y
194+unsafeWindowFunction1 fun x
195+ = UnsafeWindowFunction $ fun <> parenthesized (renderSQL x)
196+
197+-- | escape hatch for defining multi-argument window functions
198+unsafeWindowFunctionN :: SOP.SListI xs => ByteString -> WinFunN xs y
199+unsafeWindowFunctionN fun xs = UnsafeWindowFunction $ fun <>
200+ parenthesized (renderCommaSeparated renderSQL xs)
201+
202+{- | rank of the current row with gaps; same as `rowNumber` of its first peer
203+
204+>>> printSQL rank
205+rank()
206+-}
207+rank :: WinFun0 ('NotNull 'PGint8)
208+rank = UnsafeWindowFunction "rank()"
209+
210+{- | number of the current row within its partition, counting from 1
211+
212+>>> printSQL rowNumber
213+row_number()
214+-}
215+rowNumber :: WinFun0 ('NotNull 'PGint8)
216+rowNumber = UnsafeWindowFunction "row_number()"
217+
218+{- | rank of the current row without gaps; this function counts peer groups
219+
220+>>> printSQL denseRank
221+dense_rank()
222+-}
223+denseRank :: WinFun0 ('NotNull 'PGint8)
224+denseRank = UnsafeWindowFunction "dense_rank()"
225+
226+{- | relative rank of the current row: (rank - 1) / (total partition rows - 1)
227+
228+>>> printSQL percentRank
229+percent_rank()
230+-}
231+percentRank :: WinFun0 ('NotNull 'PGfloat8)
232+percentRank = UnsafeWindowFunction "percent_rank()"
233+
234+{- | cumulative distribution: (number of partition rows
235+preceding or peer with current row) / total partition rows
236+
237+>>> printSQL cumeDist
238+cume_dist()
239+-}
240+cumeDist :: WinFun0 ('NotNull 'PGfloat8)
241+cumeDist = UnsafeWindowFunction "cume_dist()"
242+
243+{- | integer ranging from 1 to the argument value,
244+dividing the partition as equally as possible
245+
246+>>> printSQL $ ntile 5
247+ntile(5)
248+-}
249+ntile :: WinFun1 ('NotNull 'PGint4) ('NotNull 'PGint4)
250+ntile = unsafeWindowFunction1 "ntile"
251+
252+{- | returns value evaluated at the row that is offset rows before the current
253+row within the partition; if there is no such row, instead return default
254+(which must be of the same type as value). Both offset and default are
255+evaluated with respect to the current row.
256+-}
257+lag :: WinFunN '[ty, 'NotNull 'PGint4, ty] ty
258+lag = unsafeWindowFunctionN "lag"
259+
260+{- | returns value evaluated at the row that is offset rows after the current
261+row within the partition; if there is no such row, instead return default
262+(which must be of the same type as value). Both offset and default are
263+evaluated with respect to the current row.
264+-}
265+lead :: WinFunN '[ty, 'NotNull 'PGint4, ty] ty
266+lead = unsafeWindowFunctionN "lead"
267+
268+{- | returns value evaluated at the row that is the
269+first row of the window frame
270+-}
271+firstValue :: WinFun1 ty ty
272+firstValue = unsafeWindowFunction1 "first_value"
273+
274+{- | returns value evaluated at the row that is the
275+last row of the window frame
276+-}
277+lastValue :: WinFun1 ty ty
278+lastValue = unsafeWindowFunction1 "last_value"
279+
280+{- | returns value evaluated at the row that is the nth
281+row of the window frame (counting from 1); null if no such row
282+-}
283+nthValue :: WinFunN '[null ty, 'NotNull 'PGint4] ('Null ty)
284+nthValue = unsafeWindowFunctionN "nth_value"
squeal-postgresql/src/Squeal/PostgreSQL/List.hsnew file+112
@@ -0,0 +1,112 @@
1+{-|
2+Module: Squeal.PostgreSQL.List
3+Description: List related types and functions
4+Copyright: (c) Eitan Chatav, 2019
5+Maintainer: eitan@morphism.tech
6+Stability: experimental
7+
8+Haskell singly-linked lists are very powerful. This module
9+provides functionality for type-level lists, heterogeneous
10+lists and type aligned lists.
11+-}
12+
13+{-# LANGUAGE
14+ DataKinds
15+ , FlexibleContexts
16+ , GADTs
17+ , LambdaCase
18+ , MultiParamTypeClasses
19+ , OverloadedStrings
20+ , PolyKinds
21+ , QuantifiedConstraints
22+ , RankNTypes
23+ , ScopedTypeVariables
24+ , TypeApplications
25+ , TypeFamilies
26+ , TypeOperators
27+ , UndecidableInstances
28+#-}
29+
30+module Squeal.PostgreSQL.List
31+ ( SOP.NP (..)
32+ , (*:)
33+ , Join
34+ , disjoin
35+ , Additional (..)
36+ , Path (..)
37+ , CFunctor (..)
38+ , CFoldable (..)
39+ , CFree (..)
40+ , Elem
41+ , In
42+ , Length
43+ ) where
44+
45+import Control.Category.Free
46+import Data.Function ((&))
47+import Data.Kind
48+import Data.Type.Bool
49+import GHC.TypeLits
50+
51+import Generics.SOP as SOP
52+
53+-- | `Join` is simply promoted `++` and is used in @JOIN@s in
54+-- `Squeal.PostgreSQL.Query.FromClause`s.
55+type family Join xs ys where
56+ Join '[] ys = ys
57+ Join (x ': xs) ys = x ': Join xs ys
58+
59+-- | `disjoin` is a utility function for splitting an `NP` list into pieces.
60+disjoin
61+ :: forall xs ys expr. SListI xs
62+ => NP expr (Join xs ys)
63+ -> (NP expr xs, NP expr ys)
64+disjoin = case sList @xs of
65+ SNil -> \ys -> (Nil, ys)
66+ SCons -> \(x :* xsys) ->
67+ case disjoin xsys of (xs,ys) -> (x :* xs, ys)
68+
69+-- | The `Additional` class is for appending
70+-- type-level list parameterized constructors such as `NP`,
71+-- `Squeal.PostgreSQL.Query.Selection`, and `Squeal.PostgreSQL.Query.FromClause`.
72+class Additional expr where
73+ also :: expr ys -> expr xs -> expr (Join xs ys)
74+instance Additional (NP expr) where
75+ also ys = \case
76+ Nil -> ys
77+ x :* xs -> x :* (xs & also ys)
78+
79+-- | A useful operator for ending an `NP` list of length at least 2 without `Nil`.
80+(*:) :: f x -> f y -> NP f '[x,y]
81+x *: y = x :* y :* Nil
82+infixl 9 *:
83+
84+-- | @Elem@ is a promoted `Data.List.elem`.
85+type family Elem x xs where
86+ Elem x '[] = 'False
87+ Elem x (x ': _) = 'True
88+ Elem x (_ ': x ': _) = 'True
89+ Elem x (_ ': _ ': x ': _) = 'True
90+ Elem x (_ ': _ ': _ ': x ': _) = 'True
91+ Elem x (_ ': _ ': _ ': _ ': x ': _) = 'True
92+ Elem x (_ ': _ ': _ ': _ ': _ ': x ': _) = 'True
93+ Elem x (_ ': xs) = Elem x xs
94+
95+-- | @In x xs@ is a constraint that proves that @x@ is in @xs@.
96+type family In x xs :: Constraint where
97+ In x xs = If (Elem x xs) (() :: Constraint)
98+ (TypeError ('ShowType x ':<>: 'Text " is not in " ':<>: 'ShowType xs))
99+
100+{- | Calculate the `Length` of a type level list
101+
102+>>> :kind! Length '[Char,String,Bool,Double]
103+Length '[Char,String,Bool,Double] :: Nat
104+= 4
105+-}
106+type family Length (xs :: [k]) :: Nat where
107+ Length (_ ': _ ': _ ': _ ': _ : xs) = 5 + Length xs
108+ Length (_ ': _ ': _ ': _ : xs) = 4 + Length xs
109+ Length (_ ': _ ': _ : xs) = 3 + Length xs
110+ Length (_ ': _ : xs) = 2 + Length xs
111+ Length (_ : xs) = 1 + Length xs
112+ Length '[] = 0
squeal-postgresql/src/Squeal/PostgreSQL/Manipulation.hs+460−268
@@ -9,228 +9,371 @@ Squeal data manipulation language.
99-}
1010
1111{-# LANGUAGE
12− DataKinds
13− , DeriveDataTypeable
14− , DeriveGeneric
12+ DeriveGeneric
1513 , FlexibleContexts
14+ , FlexibleInstances
1615 , GADTs
1716 , GeneralizedNewtypeDeriving
18− , KindSignatures
1917 , LambdaCase
18+ , MultiParamTypeClasses
2019 , OverloadedStrings
20+ , PatternSynonyms
21+ , QuantifiedConstraints
2122 , RankNTypes
22− , StandaloneDeriving
23+ , ScopedTypeVariables
24+ , TypeApplications
25+ , TypeFamilies
2326 , TypeInType
2427 , TypeOperators
28+ , UndecidableInstances
2529#-}
2630
2731module Squeal.PostgreSQL.Manipulation
2832 ( -- * Manipulation
29− Manipulation (UnsafeManipulation, renderManipulation)
33+ Manipulation_
34+ , Manipulation (..)
3035 , queryStatement
3136 -- * Insert
32− , insertRows
33− , insertQuery
34− , ReturningClause (ReturningStar, Returning)
35− , renderReturningClause
36− , ConflictClause (OnConflictDoRaise, OnConflictDoNothing, OnConflictDoUpdate)
37− , renderConflictClause
37+ , insertInto
38+ , insertInto_
3839 -- * Update
3940 , update
41+ , update_
42+ -- * Delete
4043 , deleteFrom
41− , ColumnValue (..)
44+ , deleteFrom_
45+ -- * Clauses
46+ , Optional (..)
47+ , QueryClause (..)
48+ , pattern Values_
49+ , ReturningClause (..)
50+ , pattern Returning_
51+ , ConflictClause (..)
52+ , ConflictTarget (..)
53+ , ConflictAction (..)
54+ , UsingClause (..)
4255 ) where
4356
4457import Control.DeepSeq
4558import Data.ByteString hiding (foldr)
46−import Data.Monoid
59+import Data.Kind (Type)
4760
4861import qualified Generics.SOP as SOP
4962import qualified GHC.Generics as GHC
5063
64+import Squeal.PostgreSQL.Alias
5165import Squeal.PostgreSQL.Expression
52−import Squeal.PostgreSQL.Prettyprint
66+import Squeal.PostgreSQL.Expression.Logic
67+import Squeal.PostgreSQL.List
68+import Squeal.PostgreSQL.PG
69+import Squeal.PostgreSQL.Render
5370import Squeal.PostgreSQL.Query
5471import Squeal.PostgreSQL.Schema
5572
56−-- | A `Manipulation` is a statement which may modify data in the database,
57−-- but does not alter the schema. Examples are `insertInto`, `update` and
58−-- `deleteFrom`. A `Query` is also considered a `Manipulation` even though
59−-- it does not modify data.
73+-- $setup
74+-- >>> import Squeal.PostgreSQL
75+-- >>> import Data.Int
76+-- >>> import Data.Time
77+
78+{- |
79+A `Manipulation` is a statement which may modify data in the database,
80+but does not alter its schemas. Examples are inserts, updates and deletes.
81+A `Query` is also considered a `Manipulation` even though it does not modify data.
82+
83+The general `Manipulation` type is parameterized by
84+
85+* @commons :: FromType@ - scope for all `common` table expressions,
86+* @schemas :: SchemasType@ - scope for all `table`s and `view`s,
87+* @params :: [NullityType]@ - scope for all `Squeal.Expression.Parameter.parameter`s,
88+* @row :: RowType@ - return type of the `Query`.
89+-}
6090newtype Manipulation
61− (schema :: TablesType)
91+ (commons :: FromType)
92+ (schemas :: SchemasType)
6293 (params :: [NullityType])
63− (columns :: RelationType)
94+ (columns :: RowType)
6495 = UnsafeManipulation { renderManipulation :: ByteString }
6596 deriving (GHC.Generic,Show,Eq,Ord,NFData)
97+instance RenderSQL (Manipulation commons schemas params columns) where
98+ renderSQL = renderManipulation
99+instance With Manipulation where
100+ with Done manip = manip
101+ with ctes manip = UnsafeManipulation $
102+ "WITH" <+> commaSeparated (ctoList renderSQL ctes) <+> renderSQL manip
66103
67−-- | Convert a `Query` into a `Manipulation`.
68−queryStatement
69− :: Query schema params columns
70− -> Manipulation schema params columns
71−queryStatement q = UnsafeManipulation $ renderQuery q <> ";"
104+{- |
105+The top level `Manipulation_` type is parameterized by a @schemas@ `SchemasType`,
106+against which the query is type-checked, an input @parameters@ Haskell `Type`,
107+and an ouput row Haskell `Type`.
72108
73−{-----------------------------------------
74−INSERT statements
75−-----------------------------------------}
109+A top-level `Manipulation_` can be run
110+using `Squeal.PostgreSQL.PQ.manipulateParams`, or if @parameters = ()@
111+using `Squeal.PostgreSQL.PQ.manipulate`.
76112
77−{- |
78−When a table is created, it contains no data. The first thing to do
79−before a database can be of much use is to insert data. Data is
80−conceptually inserted one row at a time. Of course you can also insert
81−more than one row, but there is no way to insert less than one row.
82−Even if you know only some column values, a complete row must be created.
113+Generally, @parameters@ will be a Haskell tuple or record whose entries
114+may be referenced using positional
115+`Squeal.PostgreSQL.Expression.Parameter.parameter`s and @row@ will be a
116+Haskell record, whose entries will be targeted using overloaded labels.
117+
118+>>> :set -XDeriveAnyClass -XDerivingStrategies
119+>>> :{
120+data Row a b = Row { col1 :: a, col2 :: b }
121+ deriving stock (GHC.Generic)
122+ deriving anyclass (SOP.Generic, SOP.HasDatatypeInfo)
123+:}
83124
84125simple insert:
85126
127+>>> type Columns = '["col1" ::: 'NoDef :=> 'Null 'PGint4, "col2" ::: 'Def :=> 'NotNull 'PGint4]
128+>>> type Schema = '["tab" ::: 'Table ('[] :=> Columns)]
86129>>> :{
87130let
88− manipulation :: Manipulation
89− '[ "tab" :::
90− '[ "col1" ::: 'Required ('NotNull 'PGint4)
91− , "col2" ::: 'Required ('NotNull 'PGint4) ]] '[] '[]
131+ manipulation :: Manipulation_ (Public Schema) () ()
92132 manipulation =
93− insertInto #tab (ColumnValues (2 `As` #col1 :* 4 `As` #col2 :* Nil) [])
94− OnConflictDoRaise (Returning Nil)
95−in renderManipulation manipulation
133+ insertInto_ #tab (Values_ (Set 2 `as` #col1 :* Default `as` #col2))
134+in printSQL manipulation
96135:}
97−"INSERT INTO tab (col1, col2) VALUES (2, 4);"
136+INSERT INTO "tab" ("col1", "col2") VALUES (2, DEFAULT)
98137
99138parameterized insert:
100139
140+>>> type Columns = '["col1" ::: 'NoDef :=> 'NotNull 'PGint4, "col2" ::: 'NoDef :=> 'NotNull 'PGint4]
141+>>> type Schema = '["tab" ::: 'Table ('[] :=> Columns)]
101142>>> :{
102143let
103− manipulation :: Manipulation
104− '[ "tab" :::
105− '[ "col1" ::: 'Required ('NotNull 'PGint4)
106− , "col2" ::: 'Required ('NotNull 'PGint4) ]]
107− '[ 'Required ('NotNull 'PGint4)
108− , 'Required ('NotNull 'PGint4) ] '[]
144+ manipulation :: Manipulation_ (Public Schema) (Int32, Int32) ()
109145 manipulation =
110− insertInto #tab
111− (ColumnValues (param @1 `As` #col1 :* param @2 `As` #col2 :* Nil) [])
112− OnConflictDoRaise (Returning Nil)
113−in renderManipulation manipulation
146+ insertInto_ #tab (Values_ (Set (param @1) `as` #col1 :* Set (param @2) `as` #col2))
147+in printSQL manipulation
114148:}
115−"INSERT INTO tab (col1, col2) VALUES (($1 :: int4), ($2 :: int4));"
149+INSERT INTO "tab" ("col1", "col2") VALUES (($1 :: int4), ($2 :: int4))
116150
117151returning insert:
118152
119153>>> :{
120154let
121− manipulation :: Manipulation
122− '[ "tab" :::
123− '[ "col1" ::: 'Required ('NotNull 'PGint4)
124− , "col2" ::: 'Required ('NotNull 'PGint4) ]] '[]
125− '["fromOnly" ::: 'Required ('NotNull 'PGint4)]
155+ manipulation :: Manipulation_ (Public Schema) () (Only Int32)
126156 manipulation =
127− insertInto #tab (ColumnValues (2 `As` #col1 :* 4 `As` #col2 :* Nil) [])
128− OnConflictDoRaise (Returning (#col1 `As` #fromOnly :* Nil))
129−in renderManipulation manipulation
157+ insertInto #tab (Values_ (Set 2 `as` #col1 :* Set 3 `as` #col2))
158+ OnConflictDoRaise (Returning (#col1 `as` #fromOnly))
159+in printSQL manipulation
130160:}
131−"INSERT INTO tab (col1, col2) VALUES (2, 4) RETURNING col1 AS fromOnly;"
161+INSERT INTO "tab" ("col1", "col2") VALUES (2, 3) RETURNING "col1" AS "fromOnly"
162+
163+upsert:
164+
165+>>> type CustomersColumns = '["name" ::: 'NoDef :=> 'NotNull 'PGtext, "email" ::: 'NoDef :=> 'NotNull 'PGtext]
166+>>> type CustomersConstraints = '["uq" ::: 'Unique '["name"]]
167+>>> type CustomersSchema = '["customers" ::: 'Table (CustomersConstraints :=> CustomersColumns)]
168+>>> :{
169+let
170+ manipulation :: Manipulation_ (Public CustomersSchema) () ()
171+ manipulation =
172+ insertInto #customers
173+ (Values_ (Set "John Smith" `as` #name :* Set "john@smith.com" `as` #email))
174+ (OnConflict (OnConstraint #uq)
175+ (DoUpdate (Set (#excluded ! #email <> "; " <> #customers ! #email) `as` #email) []))
176+ (Returning_ Nil)
177+in printSQL manipulation
178+:}
179+INSERT INTO "customers" ("name", "email") VALUES (E'John Smith', E'john@smith.com') ON CONFLICT ON CONSTRAINT "uq" DO UPDATE SET "email" = ("excluded"."email" || (E'; ' || "customers"."email"))
132180
133181query insert:
134182
135183>>> :{
136184let
137− manipulation :: Manipulation
138− '[ "tab" :::
139− '[ "col1" ::: 'Required ('NotNull 'PGint4)
140− , "col2" ::: 'Required ('NotNull 'PGint4)
141− ]
142− , "other_tab" :::
143− '[ "col1" ::: 'Required ('NotNull 'PGint4)
144− , "col2" ::: 'Required ('NotNull 'PGint4)
145− ]
146− ] '[] '[]
147− manipulation =
148− insertInto #tab
149− ( ColumnValuesQuery $
150− selectStar (from (Table (#other_tab `As` #t))) )
151− OnConflictDoRaise (Returning Nil)
152−in renderManipulation manipulation
185+ manipulation :: Manipulation_ (Public Schema) () ()
186+ manipulation = insertInto_ #tab (Subquery (select Star (from (table #tab))))
187+in printSQL manipulation
153188:}
154−"INSERT INTO tab SELECT * FROM other_tab AS t;"
189+INSERT INTO "tab" SELECT * FROM "tab" AS "tab"
155190
156−upsert:
191+update:
192+
193+>>> :{
194+let
195+ manipulation :: Manipulation_ (Public Schema) () ()
196+ manipulation = update_ #tab (Set 2 `as` #col1) (#col1 ./= #col2)
197+in printSQL manipulation
198+:}
199+UPDATE "tab" SET "col1" = 2 WHERE ("col1" <> "col2")
200+
201+delete:
157202
158203>>> :{
159204let
160− manipulation :: Manipulation
161− '[ "tab" :::
162− '[ "col1" ::: 'Required ('NotNull 'PGint4)
163− , "col2" ::: 'Required ('NotNull 'PGint4) ]]
164− '[] '[ "sum" ::: 'Required ('NotNull 'PGint4)]
205+ manipulation :: Manipulation_ (Public Schema) () (Row Int32 Int32)
206+ manipulation = deleteFrom #tab NoUsing (#col1 .== #col2) (Returning Star)
207+in printSQL manipulation
208+:}
209+DELETE FROM "tab" WHERE ("col1" = "col2") RETURNING *
210+
211+delete and using clause:
212+
213+>>> :{
214+type Schema3 =
215+ '[ "tab" ::: 'Table ('[] :=> Columns)
216+ , "other_tab" ::: 'Table ('[] :=> Columns)
217+ , "third_tab" ::: 'Table ('[] :=> Columns) ]
218+:}
219+
220+>>> :{
221+let
222+ manipulation :: Manipulation_ (Public Schema3) () ()
165223 manipulation =
166− insertInto #tab
167− (ColumnValues
168− (2 `As` #col1 :* 4 `As` #col2 :* Nil)
169− [6 `As` #col1 :* 8 `As` #col2 :* Nil])
170− (OnConflictDoUpdate
171− (Set 2 `As` #col1 :* Same `As` #col2 :* Nil)
172− (Just (#col1 .== #col2)))
173− (Returning $ (#col1 + #col2) `As` #sum :* Nil)
174−in renderManipulation manipulation
224+ deleteFrom #tab (Using (table #other_tab & also (table #third_tab)))
225+ ( (#tab ! #col2 .== #other_tab ! #col2)
226+ .&& (#tab ! #col2 .== #third_tab ! #col2) )
227+ (Returning_ Nil)
228+in printSQL manipulation
175229:}
176−"INSERT INTO tab (col1, col2) VALUES (2, 4), (6, 8) ON CONFLICT DO UPDATE SET col1 = 2 WHERE (col1 = col2) RETURNING (col1 + col2) AS sum;"
230+DELETE FROM "tab" USING "other_tab" AS "other_tab", "third_tab" AS "third_tab" WHERE (("tab"."col2" = "other_tab"."col2") AND ("tab"."col2" = "third_tab"."col2"))
231+
232+with manipulation:
233+
234+>>> type ProductsColumns = '["product" ::: 'NoDef :=> 'NotNull 'PGtext, "date" ::: 'Def :=> 'NotNull 'PGdate]
235+>>> type ProductsSchema = '["products" ::: 'Table ('[] :=> ProductsColumns), "products_deleted" ::: 'Table ('[] :=> ProductsColumns)]
236+>>> :{
237+let
238+ manipulation :: Manipulation_ (Public ProductsSchema) (Only Day) ()
239+ manipulation = with
240+ (deleteFrom #products NoUsing (#date .< param @1) (Returning Star) `as` #del)
241+ (insertInto_ #products_deleted (Subquery (select Star (from (common #del)))))
242+in printSQL manipulation
243+:}
244+WITH "del" AS (DELETE FROM "products" WHERE ("date" < ($1 :: date)) RETURNING *) INSERT INTO "products_deleted" SELECT * FROM "del" AS "del"
177245-}
178−insertRows
179− :: ( SOP.SListI columns
180− , SOP.SListI results
181− , Has tab schema table
182− , columns ~ TableToColumns table )
183− => Alias tab -- ^ table to insert into
184− -> NP (Aliased (ColumnValue '[] params)) columns
185− -> [NP (Aliased (ColumnValue '[] params)) columns]
186− -> ConflictClause columns params
187− -- ^ what to do in case of constraint conflict
188− -> ReturningClause columns params results -- ^ results to return
189− -> Manipulation schema params results
190−insertRows tab row rows conflict returning = UnsafeManipulation $
191− "INSERT" <+> "INTO" <+> renderAlias tab
192− <+> parenthesized (renderCommaSeparated renderAliasPart row)
193− <+> "VALUES"
194− <+> commaSeparated
195− ( parenthesized
196− . renderCommaSeparated renderColumnValuePart <$> row:rows )
197− <> renderConflictClause conflict
198− <> renderReturningClause returning
246+type family Manipulation_ (schemas :: SchemasType) (params :: Type) (row :: Type) where
247+ Manipulation_ schemas params row = Manipulation '[] schemas (TuplePG params) (RowPG row)
248+
249+-- | Convert a `Query` into a `Manipulation`.
250+queryStatement
251+ :: Query '[] commons schemas params columns
252+ -- ^ `Query` to embed as a `Manipulation`
253+ -> Manipulation commons schemas params columns
254+queryStatement q = UnsafeManipulation $ renderSQL q
255+
256+{-----------------------------------------
257+INSERT statements
258+-----------------------------------------}
259+
260+{- |
261+When a table is created, it contains no data. The first thing to do
262+before a database can be of much use is to insert data. Data is
263+conceptually inserted one row at a time. Of course you can also insert
264+more than one row, but there is no way to insert less than one row.
265+Even if you know only some column values, a complete row must be created.
266+-}
267+insertInto
268+ :: ( Has sch schemas schema
269+ , Has tab schema ('Table table)
270+ , columns ~ TableToColumns table
271+ , row0 ~ TableToRow table
272+ , SOP.SListI columns
273+ , SOP.SListI row1 )
274+ => QualifiedAlias sch tab
275+ -- ^ table
276+ -> QueryClause commons schemas params columns
277+ -- ^ what to insert
278+ -> ConflictClause tab commons schemas params table
279+ -- ^ what to do in case of conflict
280+ -> ReturningClause commons schemas params '[tab ::: row0] row1
281+ -- ^ what to return
282+ -> Manipulation commons schemas params row1
283+insertInto tab qry conflict ret = UnsafeManipulation $
284+ "INSERT" <+> "INTO" <+> renderSQL tab
285+ <+> renderSQL qry
286+ <> renderSQL conflict
287+ <> renderSQL ret
288+
289+-- | Like `insertInto` but with `OnConflictDoRaise` and `no` `ReturningClause`.
290+insertInto_
291+ :: ( Has sch schemas schema
292+ , Has tab schema ('Table table)
293+ , columns ~ TableToColumns table
294+ , row ~ TableToRow table
295+ , SOP.SListI columns )
296+ => QualifiedAlias sch tab
297+ -- ^ table
298+ -> QueryClause commons schemas params columns
299+ -- ^ what to insert
300+ -> Manipulation commons schemas params '[]
301+insertInto_ tab qry =
302+ insertInto tab qry OnConflictDoRaise (Returning_ Nil)
303+
304+-- | A `QueryClause` describes what to `insertInto` a table.
305+data QueryClause commons schemas params columns where
306+ Values
307+ :: SOP.SListI columns
308+ => NP (Aliased (Optional (Expression '[] commons 'Ungrouped schemas params '[]))) columns
309+ -- ^ row of values
310+ -> [NP (Aliased (Optional (Expression '[] commons 'Ungrouped schemas params '[]))) columns]
311+ -- ^ additional rows of values
312+ -> QueryClause commons schemas params columns
313+ Select
314+ :: SOP.SListI columns
315+ => NP (Aliased (Optional (Expression '[] commons grp schemas params from))) columns
316+ -- ^ row of values
317+ -> TableExpression '[] commons grp schemas params from
318+ -- ^ from a table expression
319+ -> QueryClause commons schemas params columns
320+ Subquery
321+ :: ColumnsToRow columns ~ row
322+ => Query '[] commons schemas params row
323+ -- ^ subquery to insert
324+ -> QueryClause commons schemas params columns
325+
326+instance RenderSQL (QueryClause commons schemas params columns) where
327+ renderSQL = \case
328+ Values row0 rows ->
329+ parenthesized (renderCommaSeparated renderSQLPart row0)
330+ <+> "VALUES"
331+ <+> commaSeparated
332+ ( parenthesized
333+ . renderCommaSeparated renderValuePart <$> row0 : rows )
334+ Select row0 tab ->
335+ parenthesized (renderCommaSeparatedMaybe renderSQLPartMaybe row0)
336+ <+> "SELECT"
337+ <+> renderCommaSeparatedMaybe renderValuePartMaybe row0
338+ <+> renderSQL tab
339+ Subquery qry -> renderQuery qry
199340 where
200− renderAliasPart, renderColumnValuePart
201− :: Aliased (ColumnValue '[] params) ty -> ByteString
202− renderAliasPart (_ `As` name) = renderAlias name
203− renderColumnValuePart (value `As` _) = case value of
204− Default -> "DEFAULT"
205− Set expression -> renderExpression expression
206−
207−insertQuery
208− :: ( SOP.SListI columns
209− , SOP.SListI results
210− , Has tab schema table
211− , columns ~ TableToColumns table )
212− => Alias tab -- ^ table to insert into
213− -> Query schema params (ColumnsToRelation columns)
214− -> ConflictClause columns params
215− -- ^ what to do in case of constraint conflict
216− -> ReturningClause columns params results -- ^ results to return
217− -> Manipulation schema params results
218−insertQuery tab query conflict returning = UnsafeManipulation $
219− "INSERT" <+> "INTO" <+> renderAlias tab
220− <+> renderQuery query
221− <> renderConflictClause conflict
222− <> renderReturningClause returning
223−
224−data ColumnValue
225− (columns :: RelationType)
226− (params :: [NullityType])
227− (ty :: ColumnType)
228− where
229− Same :: ColumnValue (column ': columns) params ty
230− Default :: ColumnValue columns params ('Def :=> ty)
231− Set
232− :: (forall table. Expression '[table ::: columns] 'Ungrouped params ty)
233− -> ColumnValue columns params (constraint :=> ty)
341+ renderSQLPartMaybe, renderValuePartMaybe
342+ :: Aliased (Optional (Expression '[] commons grp schemas params from)) column
343+ -> Maybe ByteString
344+ renderSQLPartMaybe = \case
345+ Default `As` _ -> Nothing
346+ Set _ `As` name -> Just $ renderSQL name
347+ renderValuePartMaybe = \case
348+ Default `As` _ -> Nothing
349+ Set value `As` _ -> Just $ renderExpression value
350+ renderSQLPart, renderValuePart
351+ :: Aliased (Optional (Expression '[] commons grp schemas params from)) column
352+ -> ByteString
353+ renderSQLPart (_ `As` name) = renderSQL name
354+ renderValuePart (value `As` _) = renderSQL value
355+
356+-- | `Values_` describes a single `NP` list of `Aliased` `Optional` `Expression`s
357+-- whose `ColumnsType` must match the tables'.
358+pattern Values_
359+ :: SOP.SListI columns
360+ => NP (Aliased (Optional (Expression '[] commons 'Ungrouped schemas params '[]))) columns
361+ -- ^ row of values
362+ -> QueryClause commons schemas params columns
363+pattern Values_ vals = Values vals []
364+
365+-- | `Optional` is either `Default` or a value, parameterized by an appropriate
366+-- `ColumnConstraint`.
367+data Optional expr ty where
368+ -- | Use the `Default` value for a column.
369+ Default :: Optional expr ('Def :=> ty)
370+ -- | `Set` a value for a column.
371+ Set :: expr ty -> Optional expr (def :=> ty)
372+
373+instance (forall x. RenderSQL (expr x)) => RenderSQL (Optional expr ty) where
374+ renderSQL = \case
375+ Default -> "DEFAULT"
376+ Set expr -> renderSQL expr
234377
235378-- | A `ReturningClause` computes and return value(s) based
236379-- on each row actually inserted, updated or deleted. This is primarily
@@ -238,71 +381,100 @@ data ColumnValue
238381-- serial sequence number. However, any expression using the table's columns
239382-- is allowed. Only rows that were successfully inserted or updated or
240383-- deleted will be returned. For example, if a row was locked
241−-- but not updated because an `OnConflictDoUpdate` condition was not satisfied,
242−-- the row will not be returned. `ReturningStar` will return all columns
243−-- in the row. Use `Returning Nil` in the common case where no return
384+-- but not updated because an `OnConflict` `DoUpdate` condition was not satisfied,
385+-- the row will not be returned. `Returning` `Star` will return all columns
386+-- in the row. Use `Returning` `Nil` in the common case where no return
244387-- values are desired.
245−data ReturningClause
246− (columns :: ColumnsType)
247− (params :: [NullityType])
248− (results :: RelationType)
249− where
250− ReturningStar
251− :: ReturningClause columns params (ColumnsToRelation columns)
252− Returning
253− :: NP
254− (Aliased (Expression '[table ::: (ColumnsToRelation columns)] 'Ungrouped params))
255− results
256− -> ReturningClause columns params results
257−
258−-- | Render a `ReturningClause`.
259−renderReturningClause
260− :: SOP.SListI results
261− => ReturningClause params columns results
262− -> ByteString
263−renderReturningClause = \case
264− ReturningStar -> " RETURNING *;"
265− Returning Nil -> ";"
266− Returning results -> " RETURNING"
267− <+> renderCommaSeparated (renderAliasedAs renderExpression) results <> ";"
388+newtype ReturningClause commons schemas params from row =
389+ Returning (Selection '[] commons 'Ungrouped schemas params from row)
390+
391+instance RenderSQL (ReturningClause commons schemas params from row) where
392+ renderSQL = \case
393+ Returning (List Nil) -> ""
394+ Returning selection -> " RETURNING" <+> renderSQL selection
395+
396+-- | `Returning` a `List`
397+pattern Returning_
398+ :: SOP.SListI row
399+ => NP (Aliased (Expression '[] commons 'Ungrouped schemas params from)) row
400+ -- ^ row of values
401+ -> ReturningClause commons schemas params from row
402+pattern Returning_ list = Returning (List list)
268403
269404-- | A `ConflictClause` specifies an action to perform upon a constraint
270405-- violation. `OnConflictDoRaise` will raise an error.
271−-- `OnConflictDoNothing` simply avoids inserting a row.
272−-- `OnConflictDoUpdate` updates the existing row that conflicts with the row
406+-- `OnConflict` `DoNothing` simply avoids inserting a row.
407+-- `OnConflict` `DoUpdate` updates the existing row that conflicts with the row
273408-- proposed for insertion.
274−data ConflictClause (columns :: ColumnsType) params where
275− OnConflictDoRaise :: ConflictClause columns params
276− OnConflictDoNothing :: ConflictClause columns params
277− OnConflictDoUpdate
278− :: NP (Aliased (ColumnValue (ColumnsToRelation columns) params)) columns
279− -> [Condition '[table ::: ColumnsToRelation columns] 'Ungrouped params]
280− -> ConflictClause columns params
409+data ConflictClause tab commons schemas params table where
410+ OnConflictDoRaise :: ConflictClause tab commons schemas params table
411+ OnConflict
412+ :: ConflictTarget constraints
413+ -- ^ conflict target
414+ -> ConflictAction tab commons schemas params columns
415+ -- ^ conflict action
416+ -> ConflictClause tab commons schemas params (constraints :=> columns)
281417
282418-- | Render a `ConflictClause`.
283−renderConflictClause
284− :: SOP.SListI columns
285− => ConflictClause columns params
419+instance SOP.SListI (TableToColumns table)
420+ => RenderSQL (ConflictClause tab commons schemas params table) where
421+ renderSQL = \case
422+ OnConflictDoRaise -> ""
423+ OnConflict target action -> " ON CONFLICT"
424+ <+> renderSQL target <+> renderSQL action
425+
426+{- |
427+`ConflictAction` specifies an alternative `OnConflict` action.
428+It can be either `DoNothing`, or a `DoUpdate` clause specifying
429+the exact details of the `update` action to be performed in case of a conflict.
430+The `Set` and WHERE `Condition`s in `OnConflict` `DoUpdate` have access to the
431+existing row using the table's name (or an alias), and to rows proposed
432+for insertion using the special @#excluded@ table.
433+`OnConflict` `DoNothing` simply avoids inserting a row as its alternative action.
434+`OnConflict` `DoUpdate` updates the existing row that conflicts
435+with the row proposed for insertion as its alternative action.
436+-}
437+data ConflictAction tab commons schemas params columns where
438+ DoNothing :: ConflictAction tab commons schemas params columns
439+ DoUpdate
440+ :: ( row ~ ColumnsToRow columns
441+ , SOP.SListI columns
442+ , columns ~ (col0 ': cols)
443+ , SOP.All (HasIn columns) subcolumns
444+ , AllUnique subcolumns )
445+ => NP (Aliased (Optional (Expression '[] commons 'Ungrouped schemas params '[tab ::: row, "excluded" ::: row]))) subcolumns
446+ -> [Condition '[] commons 'Ungrouped schemas params '[tab ::: row, "excluded" ::: row]]
447+ -- ^ WHERE `Condition`s
448+ -> ConflictAction tab commons schemas params columns
449+
450+instance RenderSQL (ConflictAction tab commons schemas params columns) where
451+ renderSQL = \case
452+ DoNothing -> "DO NOTHING"
453+ DoUpdate updates whs'
454+ -> "DO UPDATE SET"
455+ <+> renderCommaSeparated renderUpdate updates
456+ <> case whs' of
457+ [] -> ""
458+ wh:whs -> " WHERE" <+> renderSQL (foldr (.&&) wh whs)
459+
460+renderUpdate
461+ :: (forall x. RenderSQL (expr x))
462+ => Aliased (Optional expr) ty
286463 -> ByteString
287−renderConflictClause = \case
288− OnConflictDoRaise -> ""
289− OnConflictDoNothing -> " ON CONFLICT DO NOTHING"
290− OnConflictDoUpdate updates whs'
291− -> " ON CONFLICT DO UPDATE SET"
292− <+> renderCommaSeparatedMaybe renderUpdate updates
293− <> case whs' of
294− [] -> ""
295− wh:whs -> " WHERE" <+> renderExpression (foldr (.&&) wh whs)
296− where
297− renderUpdate
298− :: Aliased (ColumnValue columns params) column
299− -> Maybe ByteString
300− renderUpdate = \case
301− Same `As` _ -> Nothing
302− Default `As` column -> Just $
303− renderAlias column <+> "=" <+> "DEFAULT"
304− Set expression `As` column -> Just $
305− renderAlias column <+> "=" <+> renderExpression expression
464+renderUpdate (expr `As` col) = renderSQL col <+> "=" <+> renderSQL expr
465+
466+-- | A `ConflictTarget` specifies the constraint violation that triggers a
467+-- `ConflictAction`.
468+data ConflictTarget constraints where
469+ OnConstraint
470+ :: Has con constraints constraint
471+ => Alias con
472+ -> ConflictTarget constraints
473+
474+-- | Render a `ConflictTarget`
475+instance RenderSQL (ConflictTarget constraints) where
476+ renderSQL (OnConstraint con) =
477+ "ON" <+> "CONSTRAINT" <+> renderSQL con
306478
307479{-----------------------------------------
308480UPDATE statements
@@ -310,77 +482,97 @@ UPDATE statements
310482
311483-- | An `update` command changes the values of the specified columns
312484-- in all rows that satisfy the condition.
313−--
314−-- >>> :{
315−-- let
316−-- manipulation :: Manipulation
317−-- '[ "tab" :::
318−-- '[ "col1" ::: 'Required ('NotNull 'PGint4)
319−-- , "col2" ::: 'Required ('NotNull 'PGint4) ]] '[] '[]
320−-- manipulation =
321−-- update #tab (Set 2 `As` #col1 :* Same `As` #col2 :* Nil)
322−-- (#col1 ./= #col2) (Returning Nil)
323−-- in renderManipulation manipulation
324−-- :}
325−-- "UPDATE tab SET col1 = 2 WHERE (col1 <> col2);"
326485update
327486 :: ( SOP.SListI columns
328− , SOP.SListI results
329− , Has tab schema table
330− , columns ~ TableToColumns table )
331− => Alias tab -- ^ table to update
332− -> NP (Aliased (ColumnValue (ColumnsToRelation columns) params)) columns
487+ , SOP.SListI row1
488+ , Has sch schemas schema
489+ , Has tab schema ('Table table)
490+ , row0 ~ TableToRow table
491+ , columns ~ TableToColumns table
492+ , SOP.All (HasIn columns) subcolumns
493+ , AllUnique subcolumns )
494+ => QualifiedAlias sch tab -- ^ table to update
495+ -> NP (Aliased (Optional (Expression '[] '[] 'Ungrouped schemas params '[tab ::: row0]))) subcolumns
333496 -- ^ modified values to replace old values
334− -> Condition '[tab ::: ColumnsToRelation columns] 'Ungrouped params
497+ -> Condition '[] commons 'Ungrouped schemas params '[tab ::: row0]
335498 -- ^ condition under which to perform update on a row
336− -> ReturningClause columns params results -- ^ results to return
337− -> Manipulation schema params results
338−update table columns wh returning = UnsafeManipulation $
499+ -> ReturningClause commons schemas params '[tab ::: row0] row1 -- ^ results to return
500+ -> Manipulation commons schemas params row1
501+update tab columns wh returning = UnsafeManipulation $
339502 "UPDATE"
340− <+> renderAlias table
503+ <+> renderSQL tab
341504 <+> "SET"
342− <+> renderCommaSeparatedMaybe renderUpdate columns
343− <+> "WHERE" <+> renderExpression wh
344− <> renderReturningClause returning
345− where
346− renderUpdate
347− :: Aliased (ColumnValue columns params) column
348− -> Maybe ByteString
349− renderUpdate = \case
350− Same `As` _ -> Nothing
351− Default `As` column -> Just $
352− renderAlias column <+> "=" <+> "DEFAULT"
353− Set expression `As` column -> Just $
354− renderAlias column <+> "=" <+> renderExpression expression
505+ <+> renderCommaSeparated renderUpdate columns
506+ <+> "WHERE" <+> renderSQL wh
507+ <> renderSQL returning
508+
509+-- | Update a row returning `Nil`.
510+update_
511+ :: ( SOP.SListI columns
512+ , Has sch schemas schema
513+ , Has tab schema ('Table table)
514+ , row ~ TableToRow table
515+ , columns ~ TableToColumns table
516+ , SOP.All (HasIn columns) subcolumns
517+ , AllUnique subcolumns )
518+ => QualifiedAlias sch tab -- ^ table to update
519+ -> NP (Aliased (Optional (Expression '[] '[] 'Ungrouped schemas params '[tab ::: row]))) subcolumns
520+ -- ^ modified values to replace old values
521+ -> Condition '[] commons 'Ungrouped schemas params '[tab ::: row]
522+ -- ^ condition under which to perform update on a row
523+ -> Manipulation commons schemas params '[]
524+update_ tab columns wh = update tab columns wh (Returning_ Nil)
355525
356526{-----------------------------------------
357527DELETE statements
358528-----------------------------------------}
359529
360−-- | Delete rows of a table.
361−--
362−-- >>> :{
363−-- let
364−-- manipulation :: Manipulation
365−-- '[ "tab" :::
366−-- '[ "col1" ::: 'Required ('NotNull 'PGint4)
367−-- , "col2" ::: 'Required ('NotNull 'PGint4) ]] '[]
368−-- '[ "col1" ::: 'Required ('NotNull 'PGint4)
369−-- , "col2" ::: 'Required ('NotNull 'PGint4) ]
370−-- manipulation = deleteFrom #tab (#col1 .== #col2) ReturningStar
371−-- in renderManipulation manipulation
372−-- :}
373−-- "DELETE FROM tab WHERE (col1 = col2) RETURNING *;"
530+-- | Specify additional tables with `Using`
531+-- an `also` list of table expressions, allowing columns
532+-- from other tables to appear in the WHERE condition.
533+-- This is similar to the list of tables that can be specified
534+-- in the FROM Clause of a SELECT statement;
535+-- for example, an alias for the table name can be specified.
536+-- Do not repeat the target table in the `Using` list,
537+-- unless you wish to set up a self-join.
538+-- `NoUsing` if no additional tables are to be used.
539+data UsingClause commons schemas params from where
540+ NoUsing :: UsingClause commons schemas params '[]
541+ Using
542+ :: FromClause '[] commons schemas params from
543+ -- ^ what to use
544+ -> UsingClause commons schemas params from
545+
546+-- | Delete rows from a table.
374547deleteFrom
375− :: ( SOP.SListI results
376− , Has tab schema table
548+ :: ( SOP.SListI row1
549+ , Has sch schemas schema
550+ , Has tab schema ('Table table)
551+ , row0 ~ TableToRow table
552+ , columns ~ TableToColumns table )
553+ => QualifiedAlias sch tab -- ^ table to delete from
554+ -> UsingClause commons schemas params from
555+ -> Condition '[] commons 'Ungrouped schemas params (tab ::: row0 ': from)
556+ -- ^ condition under which to delete a row
557+ -> ReturningClause commons schemas params '[tab ::: row0] row1 -- ^ results to return
558+ -> Manipulation commons schemas params row1
559+deleteFrom tab using wh returning = UnsafeManipulation $
560+ "DELETE FROM"
561+ <+> renderSQL tab
562+ <> case using of
563+ NoUsing -> ""
564+ Using tables -> " USING" <+> renderSQL tables
565+ <+> "WHERE" <+> renderSQL wh
566+ <> renderSQL returning
567+
568+-- | Delete rows returning `Nil`.
569+deleteFrom_
570+ :: ( Has sch schemas schema
571+ , Has tab schema ('Table table)
572+ , row ~ TableToRow table
377573 , columns ~ TableToColumns table )
378− => Alias tab -- ^ table to delete from
379− -> Condition '[tab ::: ColumnsToRelation columns] 'Ungrouped params
574+ => QualifiedAlias sch tab -- ^ table to delete from
575+ -> Condition '[] commons 'Ungrouped schemas params '[tab ::: row]
380576 -- ^ condition under which to delete a row
381− -> ReturningClause columns params results -- ^ results to return
382− -> Manipulation schema params results
383−deleteFrom table wh returning = UnsafeManipulation $
384− "DELETE FROM" <+> renderAlias table
385− <+> "WHERE" <+> renderExpression wh
386− <> renderReturningClause returning
577+ -> Manipulation commons schemas params '[]
578+deleteFrom_ tab wh = deleteFrom tab NoUsing wh (Returning_ Nil)
squeal-postgresql/src/Squeal/PostgreSQL/Migration.hsnew file+448
@@ -0,0 +1,448 @@
1+{-|
2+Module: Squeal.PostgreSQL.Migration
3+Description: Squeal migrations
4+Copyright: (c) Eitan Chatav, 2017
5+Maintainer: eitan@morphism.tech
6+Stability: experimental
7+
8+This module defines a `Migration` type to safely
9+change the schema of your database over time. Let's see an example!
10+
11+First turn on some extensions.
12+
13+>>> :set -XDataKinds -XOverloadedLabels
14+>>> :set -XOverloadedStrings -XFlexibleContexts -XTypeOperators
15+
16+Next, let's define our `TableType`s.
17+
18+>>> :{
19+type UsersTable =
20+ '[ "pk_users" ::: 'PrimaryKey '["id"] ] :=>
21+ '[ "id" ::: 'Def :=> 'NotNull 'PGint4
22+ , "name" ::: 'NoDef :=> 'NotNull 'PGtext
23+ ]
24+:}
25+
26+>>> :{
27+type EmailsTable =
28+ '[ "pk_emails" ::: 'PrimaryKey '["id"]
29+ , "fk_user_id" ::: 'ForeignKey '["user_id"] "users" '["id"]
30+ ] :=>
31+ '[ "id" ::: 'Def :=> 'NotNull 'PGint4
32+ , "user_id" ::: 'NoDef :=> 'NotNull 'PGint4
33+ , "email" ::: 'NoDef :=> 'Null 'PGtext
34+ ]
35+:}
36+
37+Now we can define some `Migration`s to make our tables.
38+
39+>>> :{
40+let
41+ makeUsers :: Migration Definition (Public '[]) '["public" ::: '["users" ::: 'Table UsersTable]]
42+ makeUsers = Migration
43+ { name = "make users table"
44+ , up = createTable #users
45+ ( serial `as` #id :*
46+ notNullable text `as` #name )
47+ ( primaryKey #id `as` #pk_users )
48+ , down = dropTable #users
49+ }
50+:}
51+
52+>>> :{
53+let
54+ makeEmails :: Migration Definition '["public" ::: '["users" ::: 'Table UsersTable]]
55+ '["public" ::: '["users" ::: 'Table UsersTable, "emails" ::: 'Table EmailsTable]]
56+ makeEmails = Migration
57+ { name = "make emails table"
58+ , up = createTable #emails
59+ ( serial `as` #id :*
60+ notNullable int `as` #user_id :*
61+ nullable text `as` #email )
62+ ( primaryKey #id `as` #pk_emails :*
63+ foreignKey #user_id #users #id
64+ OnDeleteCascade OnUpdateCascade `as` #fk_user_id )
65+ , down = dropTable #emails
66+ }
67+:}
68+
69+Now that we have a couple migrations we can chain them together into a `Path`.
70+
71+>>> let migrations = makeUsers :>> makeEmails :>> Done
72+
73+Now run the migrations.
74+
75+>>> import Control.Monad.IO.Class
76+>>> :{
77+withConnection "host=localhost port=5432 dbname=exampledb" $
78+ manipulate (UnsafeManipulation "SET client_min_messages TO WARNING;")
79+ -- suppress notices
80+ & pqThen (liftIO (putStrLn "Migrate"))
81+ & pqThen (migrateUp migrations)
82+ & pqThen (liftIO (putStrLn "Rollback"))
83+ & pqThen (migrateDown migrations)
84+:}
85+Migrate
86+Rollback
87+
88+We can also create a simple executable using `defaultMain`.
89+
90+>>> let main = defaultMain "host=localhost port=5432 dbname=exampledb" migrations
91+
92+>>> withArgs [] main
93+Invalid command: "". Use:
94+migrate to run all available migrations
95+rollback to rollback all available migrations
96+status to display migrations run and migrations left to run
97+
98+>>> withArgs ["status"] main
99+Migrations already run:
100+ None
101+Migrations left to run:
102+ - make users table
103+ - make emails table
104+
105+>>> withArgs ["migrate"] main
106+Migrations already run:
107+ - make users table
108+ - make emails table
109+Migrations left to run:
110+ None
111+
112+>>> withArgs ["rollback"] main
113+Migrations already run:
114+ None
115+Migrations left to run:
116+ - make users table
117+ - make emails table
118+
119+In addition to enabling `Migration`s using pure SQL `Definition`s for
120+the `up` and `down` instructions, you can also perform impure `IO` actions
121+by using a `Migration`s over the `Terminally` `PQ` `IO` category.
122+-}
123+
124+{-# LANGUAGE
125+ DataKinds
126+ , DeriveGeneric
127+ , FlexibleContexts
128+ , FlexibleInstances
129+ , GADTs
130+ , LambdaCase
131+ , OverloadedLabels
132+ , OverloadedStrings
133+ , PolyKinds
134+ , QuantifiedConstraints
135+ , RankNTypes
136+ , TypeApplications
137+ , TypeOperators
138+#-}
139+
140+module Squeal.PostgreSQL.Migration
141+ ( -- * Migration
142+ Migration (..)
143+ , Migratory (..)
144+ , Terminally (..)
145+ , terminally
146+ , pureMigration
147+ , MigrationsTable
148+ , defaultMain
149+ ) where
150+
151+import Control.Category
152+import Control.Monad
153+import Data.ByteString (ByteString)
154+import Data.Foldable (traverse_)
155+import Data.Function ((&))
156+import Data.List ((\\))
157+import Data.Text (Text)
158+import Data.Time (UTCTime)
159+import Prelude hiding ((.), id)
160+import System.Environment
161+import UnliftIO (MonadIO (..))
162+
163+import qualified Data.Text.IO as Text (putStrLn)
164+import qualified Generics.SOP as SOP
165+import qualified GHC.Generics as GHC
166+
167+import Squeal.PostgreSQL.Alias
168+import Squeal.PostgreSQL.Binary
169+import Squeal.PostgreSQL.Definition
170+import Squeal.PostgreSQL.Definition.Table
171+import Squeal.PostgreSQL.Definition.Table.Constraint
172+import Squeal.PostgreSQL.Expression.Comparison
173+import Squeal.PostgreSQL.Expression.Parameter
174+import Squeal.PostgreSQL.Expression.Time
175+import Squeal.PostgreSQL.Expression.Type
176+import Squeal.PostgreSQL.List
177+import Squeal.PostgreSQL.Manipulation
178+import Squeal.PostgreSQL.PQ
179+import Squeal.PostgreSQL.Query
180+import Squeal.PostgreSQL.Schema
181+import Squeal.PostgreSQL.Transaction
182+
183+-- | A `Migration` is a named "isomorphism" over a given category.
184+-- It should contain an inverse pair of `up` and `down`
185+-- instructions and a unique `name`.
186+data Migration p schemas0 schemas1 = Migration
187+ { name :: Text -- ^ The `name` of a `Migration`.
188+ -- Each `name` in a `Migration` should be unique.
189+ , up :: p schemas0 schemas1 -- ^ The `up` instruction of a `Migration`.
190+ , down :: p schemas1 schemas0 -- ^ The `down` instruction of a `Migration`.
191+ } deriving (GHC.Generic)
192+
193+{- |
194+A `Migratory` @p@ is a `Category` for which one can execute or rewind
195+a `Path` of `Migration`s over @p@. This includes the category of pure
196+SQL `Definition`s and the category of impure `Terminally` `PQ` `IO` actions.
197+-}
198+class Category p => Migratory p where
199+
200+ {- |
201+ Run a `Path` of `Migration`s.
202+ Create the `MigrationsTable` as @public.schema_migrations@ if it does not already exist.
203+ In one transaction, for each each `Migration` query to see if the `Migration` has been executed;
204+ if not, `up` the `Migration` and insert its `name` in the `MigrationsTable`.
205+ -}
206+ migrateUp
207+ :: Path (Migration p) schemas0 schemas1
208+ -> PQ schemas0 schemas1 IO ()
209+
210+ {- |
211+ Rewind a `Path` of `Migration`s.
212+ Create the `MigrationsTable` as @public.schema_migrations@ if it does not already exist.
213+ In one transaction, for each each `Migration` query to see if the `Migration` has been executed;
214+ if so, `down` the `Migration` and delete its `name` in the `MigrationsTable`.
215+ -}
216+ migrateDown
217+ :: Path (Migration p) schemas0 schemas1
218+ -> PQ schemas1 schemas0 IO ()
219+
220+instance Migratory Definition where
221+ migrateUp = migrateUp . cmap pureMigration
222+ migrateDown = migrateDown . cmap pureMigration
223+
224+{- | `Terminally` turns an indexed monad transformer and the monad it transforms
225+into a category by restricting the return type to @()@ and permuting the type variables.
226+This is similar to how applying a monad to @()@ yields a monoid.
227+Since a `Terminally` action has a trivial return value, the only reason
228+to run one is for the side effects, in particular database and other IO effects.
229+-}
230+newtype Terminally trans monad x0 x1 = Terminally
231+ { runTerminally :: trans x0 x1 monad () }
232+ deriving GHC.Generic
233+
234+instance
235+ ( IndexedMonadTransPQ trans
236+ , Monad monad
237+ , forall x0 x1. x0 ~ x1 => Monad (trans x0 x1 monad) )
238+ => Category (Terminally trans monad) where
239+ id = Terminally (return ())
240+ Terminally g . Terminally f = Terminally $ pqThen g f
241+
242+-- | `terminally` ignores the output of a computation, returning @()@ and
243+-- wrapping it up into a `Terminally`. You can lift an action in the base monad
244+-- by using @terminally . lift@.
245+terminally
246+ :: Functor (trans x0 x1 monad)
247+ => trans x0 x1 monad ignore
248+ -> Terminally trans monad x0 x1
249+terminally = Terminally . void
250+
251+-- | A `pureMigration` turns a `Migration` involving only pure SQL
252+-- `Definition`s into a `Migration` that may be combined with arbitrary `IO`.
253+pureMigration
254+ :: Migration Definition schemas0 schemas1
255+ -> Migration (Terminally PQ IO) schemas0 schemas1
256+pureMigration migration = Migration
257+ { name = name migration
258+ , up = terminally . define $ up migration
259+ , down = terminally . define $ down migration
260+ }
261+
262+instance Migratory (Terminally PQ IO) where
263+
264+ migrateUp migration = unsafePQ . transactionally_ $ do
265+ define createMigrations
266+ upMigrations migration
267+
268+ where
269+
270+ upMigrations
271+ :: Path (Migration (Terminally PQ IO)) schemas0 schemas1
272+ -> PQ MigrationsSchemas MigrationsSchemas IO ()
273+ upMigrations = \case
274+ Done -> return ()
275+ step :>> steps -> upMigration step >> upMigrations steps
276+
277+ upMigration
278+ :: Migration (Terminally PQ IO) schemas0 schemas1
279+ -> PQ MigrationsSchemas MigrationsSchemas IO ()
280+ upMigration step = do
281+ executed <- queryExecuted step
282+ unless (executed == 1) $ do
283+ unsafePQ . runTerminally $ up step
284+ manipulateParams_ insertMigration (Only (name step))
285+
286+ queryExecuted
287+ :: Migration (Terminally PQ IO) schemas0 schemas1
288+ -> PQ MigrationsSchemas MigrationsSchemas IO Row
289+ queryExecuted step = do
290+ result <- runQueryParams selectMigration (Only (name step))
291+ ntuples result
292+
293+ migrateDown migrations = unsafePQ . transactionally_ $ do
294+ define createMigrations
295+ downMigrations migrations
296+
297+ where
298+
299+ downMigrations
300+ :: Path (Migration (Terminally PQ IO)) schemas0 schemas1
301+ -> PQ MigrationsSchemas MigrationsSchemas IO ()
302+ downMigrations = \case
303+ Done -> return ()
304+ step :>> steps -> downMigrations steps >> downMigration step
305+
306+ downMigration
307+ :: Migration (Terminally PQ IO) schemas0 schemas1
308+ -> PQ MigrationsSchemas MigrationsSchemas IO ()
309+ downMigration step = do
310+ executed <- queryExecuted step
311+ unless (executed == 0) $ do
312+ unsafePQ . runTerminally $ down step
313+ manipulateParams_ deleteMigration (Only (name step))
314+
315+ queryExecuted
316+ :: Migration (Terminally PQ IO) schemas0 schemas1
317+ -> PQ MigrationsSchemas MigrationsSchemas IO Row
318+ queryExecuted step = do
319+ result <- runQueryParams selectMigration (Only (name step))
320+ ntuples result
321+
322+unsafePQ :: (Functor m) => PQ db0 db1 m x -> PQ db0' db1' m x
323+unsafePQ (PQ pq) = PQ $ fmap (SOP.K . SOP.unK) . pq . SOP.K . SOP.unK
324+
325+-- | The `TableType` for a Squeal migration.
326+type MigrationsTable =
327+ '[ "migrations_unique_name" ::: 'Unique '["name"]] :=>
328+ '[ "name" ::: 'NoDef :=> 'NotNull 'PGtext
329+ , "executed_at" ::: 'Def :=> 'NotNull 'PGtimestamptz
330+ ]
331+
332+data MigrationRow =
333+ MigrationRow { migrationName :: Text
334+ , migrationTime :: UTCTime }
335+ deriving (GHC.Generic, Show)
336+
337+instance SOP.Generic MigrationRow
338+instance SOP.HasDatatypeInfo MigrationRow
339+
340+type MigrationsSchema = '["schema_migrations" ::: 'Table MigrationsTable]
341+type MigrationsSchemas = Public MigrationsSchema
342+
343+-- | Creates a `MigrationsTable` if it does not already exist.
344+createMigrations :: Definition MigrationsSchemas MigrationsSchemas
345+createMigrations =
346+ createTableIfNotExists #schema_migrations
347+ ( (text & notNullable) `as` #name :*
348+ (timestampWithTimeZone & notNullable & default_ currentTimestamp)
349+ `as` #executed_at )
350+ ( unique #name `as` #migrations_unique_name )
351+
352+-- | Inserts a `Migration` into the `MigrationsTable`, returning
353+-- the time at which it was inserted.
354+insertMigration :: Manipulation_ MigrationsSchemas (Only Text) ()
355+insertMigration = insertInto_ #schema_migrations
356+ (Values_ (Set (param @1) `as` #name :* Default `as` #executed_at))
357+
358+-- | Deletes a `Migration` from the `MigrationsTable`, returning
359+-- the time at which it was inserted.
360+deleteMigration :: Manipulation_ MigrationsSchemas (Only Text) ()
361+deleteMigration = deleteFrom_ #schema_migrations (#name .== param @1)
362+
363+-- | Selects a `Migration` from the `MigrationsTable`, returning
364+-- the time at which it was inserted.
365+selectMigration
366+ :: Query_ MigrationsSchemas (Only Text) (Only UTCTime)
367+selectMigration = select_ (#executed_at `as` #fromOnly)
368+ $ from (table (#schema_migrations))
369+ & where_ (#name .== param @1)
370+
371+selectMigrations :: Query_ MigrationsSchemas () MigrationRow
372+selectMigrations = select_
373+ (#name `as` #migrationName :* #executed_at `as` #migrationTime)
374+ (from (table #schema_migrations))
375+
376+data MigrateCommand
377+ = MigrateStatus
378+ | MigrateUp
379+ | MigrateDown deriving (GHC.Generic, Show)
380+
381+{- | `defaultMain` creates a simple executable
382+from a connection string and a list of `Migration`s. -}
383+defaultMain
384+ :: Migratory p
385+ => ByteString
386+ -- ^ connection string
387+ -> Path (Migration p) db0 db1
388+ -- ^ migrations
389+ -> IO ()
390+defaultMain connectTo migrations = do
391+ command <- readCommandFromArgs
392+ maybe (pure ()) performCommand command
393+
394+ where
395+
396+ performCommand :: MigrateCommand -> IO ()
397+ performCommand = \case
398+ MigrateStatus -> withConnection connectTo $
399+ suppressNotices >> migrateStatus
400+ MigrateUp -> withConnection connectTo $
401+ suppressNotices & pqThen (migrateUp migrations) & pqThen migrateStatus
402+ MigrateDown -> withConnection connectTo $
403+ suppressNotices & pqThen (migrateDown migrations) & pqThen migrateStatus
404+
405+ migrateStatus :: PQ schema schema IO ()
406+ migrateStatus = unsafePQ $ do
407+ runNames <- getRunMigrationNames
408+ let names = ctoList name migrations
409+ unrunNames = names \\ runNames
410+ liftIO $ displayRunned runNames >> displayUnrunned unrunNames
411+
412+ suppressNotices :: PQ schema schema IO ()
413+ suppressNotices = manipulate_ $
414+ UnsafeManipulation "SET client_min_messages TO WARNING;"
415+
416+ readCommandFromArgs :: IO (Maybe MigrateCommand)
417+ readCommandFromArgs = getArgs >>= \case
418+ ["migrate"] -> pure . Just $ MigrateUp
419+ ["rollback"] -> pure . Just $ MigrateDown
420+ ["status"] -> pure . Just $ MigrateStatus
421+ args -> displayUsage args >> pure Nothing
422+
423+ displayUsage :: [String] -> IO ()
424+ displayUsage args = do
425+ putStrLn $ "Invalid command: \"" <> unwords args <> "\". Use:"
426+ putStrLn "migrate to run all available migrations"
427+ putStrLn "rollback to rollback all available migrations"
428+ putStrLn "status to display migrations run and migrations left to run"
429+
430+ getRunMigrationNames :: (MonadIO m) => PQ db0 db0 m [Text]
431+ getRunMigrationNames =
432+ fmap migrationName <$> (unsafePQ (define createMigrations & pqThen (runQuery selectMigrations)) >>= getRows)
433+
434+ displayListOfNames :: [Text] -> IO ()
435+ displayListOfNames [] = Text.putStrLn " None"
436+ displayListOfNames xs =
437+ let singleName n = Text.putStrLn $ " - " <> n
438+ in traverse_ singleName xs
439+
440+ displayUnrunned :: [Text] -> IO ()
441+ displayUnrunned unrunned =
442+ Text.putStrLn "Migrations left to run:"
443+ >> displayListOfNames unrunned
444+
445+ displayRunned :: [Text] -> IO ()
446+ displayRunned runned =
447+ Text.putStrLn "Migrations already run:"
448+ >> displayListOfNames runned
squeal-postgresql/src/Squeal/PostgreSQL/PG.hsnew file+388
@@ -0,0 +1,388 @@
1+{-|
2+Module: Squeal.PostgreSQL.PG
3+Description: Embedding of Haskell types into Postgres's type system
4+Copyright: (c) Eitan Chatav, 2010
5+Maintainer: eitan@morphism.tech
6+Stability: experimental
7+
8+`Squeal.PostgreSQL.PG` provides type families for turning Haskell
9+`Type`s into corresponding Postgres types.
10+-}
11+{-# LANGUAGE
12+ AllowAmbiguousTypes
13+ , DeriveAnyClass
14+ , DeriveFoldable
15+ , DeriveFunctor
16+ , DeriveGeneric
17+ , DeriveTraversable
18+ , DerivingStrategies
19+ , DefaultSignatures
20+ , FlexibleContexts
21+ , FlexibleInstances
22+ , FunctionalDependencies
23+ , GADTs
24+ , LambdaCase
25+ , MultiParamTypeClasses
26+ , OverloadedStrings
27+ , ScopedTypeVariables
28+ , TypeApplications
29+ , TypeFamilies
30+ , TypeInType
31+ , TypeOperators
32+ , UndecidableInstances
33+ , UndecidableSuperClasses
34+#-}
35+
36+module Squeal.PostgreSQL.PG
37+ ( -- * PG embeddings
38+ PG
39+ , NullPG
40+ , TuplePG
41+ , RowPG
42+ -- * Storage newtypes
43+ , Money (..)
44+ , Json (..)
45+ , Jsonb (..)
46+ , Composite (..)
47+ , Enumerated (..)
48+ , VarArray (..)
49+ , FixArray (..)
50+ , LibPQ.Oid (..)
51+ -- * Type families
52+ , LabelsPG
53+ , DimPG
54+ , FixPG
55+ , TupleOf
56+ , TupleCodeOf
57+ , RowOf
58+ , ConstructorsOf
59+ , ConstructorNameOf
60+ , ConstructorNamesOf
61+ ) where
62+
63+import Data.Aeson (Value)
64+import Data.Kind (Type)
65+import Data.Int (Int16, Int32, Int64)
66+import Data.Scientific (Scientific)
67+import Data.Time (Day, DiffTime, LocalTime, TimeOfDay, TimeZone, UTCTime)
68+import Data.Vector (Vector)
69+import Data.UUID.Types (UUID)
70+import GHC.TypeLits
71+import Network.IP.Addr (NetAddr, IP)
72+
73+import qualified Data.ByteString.Lazy as Lazy (ByteString)
74+import qualified Data.ByteString as Strict (ByteString)
75+import qualified Data.Text.Lazy as Lazy (Text)
76+import qualified Data.Text as Strict (Text)
77+import qualified Database.PostgreSQL.LibPQ as LibPQ
78+import qualified GHC.Generics as GHC
79+import qualified Generics.SOP as SOP
80+import qualified Generics.SOP.Record as SOP
81+import qualified Generics.SOP.Type.Metadata as Type
82+
83+import Squeal.PostgreSQL.Alias
84+import Squeal.PostgreSQL.Schema
85+
86+-- $setup
87+-- >>> import Squeal.PostgreSQL
88+-- >>> import Data.Text (Text)
89+
90+{- | The `PG` type family embeds a subset of Haskell types
91+as Postgres types. As an open type family, `PG` is extensible.
92+
93+>>> :kind! PG LocalTime
94+PG LocalTime :: PGType
95+= 'PGtimestamp
96+
97+>>> newtype MyDouble = My Double
98+>>> :set -XTypeFamilies
99+>>> type instance PG MyDouble = 'PGfloat8
100+-}
101+type family PG (hask :: Type) :: PGType
102+-- | `PGbool`
103+type instance PG Bool = 'PGbool
104+-- | `PGint2`
105+type instance PG Int16 = 'PGint2
106+-- | `PGint4`
107+type instance PG Int32 = 'PGint4
108+-- | `PGint8`
109+type instance PG Int64 = 'PGint8
110+-- | `PGint2`
111+type instance PG LibPQ.Oid = 'PGoid
112+-- | `PGnumeric`
113+type instance PG Scientific = 'PGnumeric
114+-- | `PGfloat4`
115+type instance PG Float = 'PGfloat4
116+-- | `PGfloat8`
117+type instance PG Double = 'PGfloat8
118+-- | `PGchar` @1@
119+type instance PG Char = 'PGchar 1
120+-- | `PGtext`
121+type instance PG Strict.Text = 'PGtext
122+-- | `PGtext`
123+type instance PG Lazy.Text = 'PGtext
124+-- | `PGtext`
125+type instance PG String = 'PGtext
126+-- | `PGbytea`
127+type instance PG Strict.ByteString = 'PGbytea
128+-- | `PGbytea`
129+type instance PG Lazy.ByteString = 'PGbytea
130+-- | `PGtimestamp`
131+type instance PG LocalTime = 'PGtimestamp
132+-- | `PGtimestamptz`
133+type instance PG UTCTime = 'PGtimestamptz
134+-- | `PGdate`
135+type instance PG Day = 'PGdate
136+-- | `PGtime`
137+type instance PG TimeOfDay = 'PGtime
138+-- | `PGtimetz`
139+type instance PG (TimeOfDay, TimeZone) = 'PGtimetz
140+-- | `PGinterval`
141+type instance PG DiffTime = 'PGinterval
142+-- | `PGuuid`
143+type instance PG UUID = 'PGuuid
144+-- | `PGinet`
145+type instance PG (NetAddr IP) = 'PGinet
146+-- | `PGjson`
147+type instance PG Value = 'PGjson
148+
149+{-| The `LabelsPG` type family calculates the constructors of a
150+Haskell enum type.
151+
152+>>> data Schwarma = Beef | Lamb | Chicken deriving GHC.Generic
153+>>> instance SOP.Generic Schwarma
154+>>> instance SOP.HasDatatypeInfo Schwarma
155+>>> :kind! LabelsPG Schwarma
156+LabelsPG Schwarma :: [Type.ConstructorName]
157+= '["Beef", "Lamb", "Chicken"]
158+-}
159+type family LabelsPG (hask :: Type) :: [Type.ConstructorName] where
160+ LabelsPG hask =
161+ ConstructorNamesOf (ConstructorsOf (SOP.DatatypeInfoOf hask))
162+
163+{- |
164+`RowPG` turns a Haskell `Type` into a `RowType`.
165+
166+`RowPG` may be applied to normal Haskell record types provided they
167+have `SOP.Generic` and `SOP.HasDatatypeInfo` instances;
168+
169+>>> data Person = Person { name :: Strict.Text, age :: Int32 } deriving GHC.Generic
170+>>> instance SOP.Generic Person
171+>>> instance SOP.HasDatatypeInfo Person
172+>>> :kind! RowPG Person
173+RowPG Person :: [(Symbol, NullityType)]
174+= '["name" ::: 'NotNull 'PGtext, "age" ::: 'NotNull 'PGint4]
175+-}
176+type family RowPG (hask :: Type) :: RowType where
177+ RowPG hask = RowOf (SOP.RecordCodeOf hask)
178+
179+-- | `RowOf` applies `NullPG` to the fields of a list.
180+type family RowOf (record :: [(Symbol, Type)]) :: RowType where
181+ RowOf (col ::: ty ': col1 ::: ty1 ': col2 ::: ty2 ': col3 ::: ty3 ': col4 ::: ty4 ': record) =
182+ col ::: NullPG ty ': col1 ::: NullPG ty1 ': col2 ::: NullPG ty2 ': col3 ::: NullPG ty3 ': col4 ::: NullPG ty4 ': RowOf record
183+ RowOf (col ::: ty ': col1 ::: ty1 ': col2 ::: ty2 ': col3 ::: ty3 ': record) =
184+ col ::: NullPG ty ': col1 ::: NullPG ty1 ': col2 ::: NullPG ty2 ': col3 ::: NullPG ty3 ': RowOf record
185+ RowOf (col ::: ty ': col1 ::: ty1 ': col2 ::: ty2 ': record) =
186+ col ::: NullPG ty ': col1 ::: NullPG ty1 ': col2 ::: NullPG ty2 ': RowOf record
187+ RowOf (col ::: ty ': col1 ::: ty1 ': record) =
188+ col ::: NullPG ty ': col1::: NullPG ty1 ': RowOf record
189+ RowOf (col ::: ty ': record) = col ::: NullPG ty ': RowOf record
190+ RowOf '[] = '[]
191+
192+{- | `NullPG` turns a Haskell type into a `NullityType`.
193+
194+>>> :kind! NullPG Double
195+NullPG Double :: NullityType
196+= 'NotNull 'PGfloat8
197+>>> :kind! NullPG (Maybe Double)
198+NullPG (Maybe Double) :: NullityType
199+= 'Null 'PGfloat8
200+-}
201+type family NullPG (hask :: Type) :: NullityType where
202+ NullPG (Maybe hask) = 'Null (PG hask)
203+ NullPG hask = 'NotNull (PG hask)
204+
205+{- | `TuplePG` turns a Haskell tuple type (including record types) into
206+the corresponding list of `NullityType`s.
207+
208+>>> :kind! TuplePG (Double, Maybe Char)
209+TuplePG (Double, Maybe Char) :: [NullityType]
210+= '[ 'NotNull 'PGfloat8, 'Null ('PGchar 1)]
211+-}
212+type family TuplePG (hask :: Type) :: [NullityType] where
213+ TuplePG hask = TupleOf (TupleCodeOf hask (SOP.Code hask))
214+
215+-- | `TupleOf` turns a list of Haskell `Type`s into a list of `NullityType`s.
216+type family TupleOf (tuple :: [Type]) :: [NullityType] where
217+ TupleOf (hask ': hask1 ': hask2 ': hask3 ': hask4 ': hask5 ': tuple) =
218+ NullPG hask ': NullPG hask1 ': NullPG hask2 ': NullPG hask3 ': NullPG hask4 ': NullPG hask5 ': TupleOf tuple
219+ TupleOf (hask ': hask1 ': hask2 ': hask3 ': hask4 ': tuple) =
220+ NullPG hask ': NullPG hask1 ': NullPG hask2 ': NullPG hask3 ': NullPG hask4 ': TupleOf tuple
221+ TupleOf (hask ': hask1 ': hask2 ': hask3 ': tuple) =
222+ NullPG hask ': NullPG hask1 ': NullPG hask2 ': NullPG hask3 ': TupleOf tuple
223+ TupleOf (hask ': hask1 ': hask2 ': tuple) =
224+ NullPG hask ': NullPG hask1 ': NullPG hask2 ': TupleOf tuple
225+ TupleOf (hask ': hask1 ': tuple) = NullPG hask ': NullPG hask1 ': TupleOf tuple
226+ TupleOf (hask ': tuple) = NullPG hask ': TupleOf tuple
227+ TupleOf '[] = '[]
228+
229+-- | `TupleCodeOf` takes the `SOP.Code` of a haskell `Type`
230+-- and if it's a simple product returns it, otherwise giving a `TypeError`.
231+type family TupleCodeOf (hask :: Type) (code :: [[Type]]) :: [Type] where
232+ TupleCodeOf hask '[tuple] = tuple
233+ TupleCodeOf hask '[] =
234+ TypeError
235+ ( 'Text "The type `" ':<>: 'ShowType hask ':<>: 'Text "' is not a tuple type."
236+ ':$$: 'Text "It is a void type with no constructors."
237+ )
238+ TupleCodeOf hask (_ ': _ ': _) =
239+ TypeError
240+ ( 'Text "The type `" ':<>: 'ShowType hask ':<>: 'Text "' is not a tuple type."
241+ ':$$: 'Text "It is a sum type with more than one constructor."
242+ )
243+
244+-- | Calculates constructors of a datatype.
245+type family ConstructorsOf (datatype :: Type.DatatypeInfo)
246+ :: [Type.ConstructorInfo] where
247+ ConstructorsOf ('Type.ADT _module _datatype constructors) =
248+ constructors
249+ ConstructorsOf ('Type.Newtype _module _datatype constructor) =
250+ '[constructor]
251+
252+-- | Calculates the name of a nullary constructor, otherwise
253+-- generates a type error.
254+type family ConstructorNameOf (constructor :: Type.ConstructorInfo)
255+ :: Type.ConstructorName where
256+ ConstructorNameOf ('Type.Constructor name) = name
257+ ConstructorNameOf ('Type.Infix name _assoc _fix) = TypeError
258+ ('Text "ConstructorNameOf error: non-nullary constructor "
259+ ':<>: 'Text name)
260+ ConstructorNameOf ('Type.Record name _fields) = TypeError
261+ ('Text "ConstructorNameOf error: non-nullary constructor "
262+ ':<>: 'Text name)
263+
264+-- | Calculate the names of nullary constructors.
265+type family ConstructorNamesOf (constructors :: [Type.ConstructorInfo])
266+ :: [Type.ConstructorName] where
267+ ConstructorNamesOf '[] = '[]
268+ ConstructorNamesOf (constructor ': constructors) =
269+ ConstructorNameOf constructor ': ConstructorNamesOf constructors
270+
271+-- | `DimPG` turns Haskell nested homogeneous tuples into a list of lengths.
272+type family DimPG (hask :: Type) :: [Nat] where
273+ DimPG (x,x) = 2 ': DimPG x
274+ DimPG (x,x,x) = 3 ': DimPG x
275+ DimPG (x,x,x,x) = 4 ': DimPG x
276+ DimPG (x,x,x,x,x) = 5 ': DimPG x
277+ DimPG (x,x,x,x,x,x) = 6 ': DimPG x
278+ DimPG (x,x,x,x,x,x,x) = 7 ': DimPG x
279+ DimPG (x,x,x,x,x,x,x,x) = 8 ': DimPG x
280+ DimPG (x,x,x,x,x,x,x,x,x) = 9 ': DimPG x
281+ DimPG (x,x,x,x,x,x,x,x,x,x) = 10 ': DimPG x
282+ DimPG x = '[]
283+
284+-- | `FixPG` extracts `NullPG` of the base type of nested homogeneous tuples.
285+type family FixPG (hask :: Type) :: NullityType where
286+ FixPG (x,x) = FixPG x
287+ FixPG (x,x,x) = FixPG x
288+ FixPG (x,x,x,x) = FixPG x
289+ FixPG (x,x,x,x,x) = FixPG x
290+ FixPG (x,x,x,x,x,x) = FixPG x
291+ FixPG (x,x,x,x,x,x,x) = FixPG x
292+ FixPG (x,x,x,x,x,x,x,x) = FixPG x
293+ FixPG (x,x,x,x,x,x,x,x,x) = FixPG x
294+ FixPG (x,x,x,x,x,x,x,x,x,x) = FixPG x
295+ FixPG (x,x,x,x,x,x,x,x,x,x,x) = FixPG x
296+ FixPG x = NullPG x
297+
298+{- | The `Money` newtype stores a monetary value in terms
299+of the number of cents, i.e. @$2,000.20@ would be expressed as
300+@Money { cents = 200020 }@.
301+
302+>>> import Control.Monad (void)
303+>>> import Control.Monad.IO.Class (liftIO)
304+>>> import Squeal.PostgreSQL
305+>>> :{
306+let
307+ roundTrip :: Query_ (Public '[]) (Only Money) (Only Money)
308+ roundTrip = values_ $ parameter @1 money `as` #fromOnly
309+:}
310+
311+>>> let input = Only (Money 20020)
312+
313+>>> :{
314+withConnection "host=localhost port=5432 dbname=exampledb" $ do
315+ result <- runQueryParams roundTrip input
316+ Just output <- firstRow result
317+ liftIO . print $ input == output
318+:}
319+True
320+-}
321+newtype Money = Money { cents :: Int64 }
322+ deriving stock (Eq, Ord, Show, Read, GHC.Generic)
323+ deriving anyclass (SOP.HasDatatypeInfo, SOP.Generic)
324+-- | `PGmoney`
325+type instance PG Money = 'PGmoney
326+
327+{- | The `Json` newtype is an indication that the Haskell
328+type it's applied to should be stored as a `PGjson`.
329+-}
330+newtype Json hask = Json {getJson :: hask}
331+ deriving stock (Eq, Ord, Show, Read, GHC.Generic)
332+ deriving anyclass (SOP.HasDatatypeInfo, SOP.Generic)
333+-- | `PGjson`
334+type instance PG (Json hask) = 'PGjson
335+
336+{- | The `Jsonb` newtype is an indication that the Haskell
337+type it's applied to should be stored as a `PGjsonb`.
338+-}
339+newtype Jsonb hask = Jsonb {getJsonb :: hask}
340+ deriving stock (Eq, Ord, Show, Read, GHC.Generic)
341+ deriving anyclass (SOP.HasDatatypeInfo, SOP.Generic)
342+-- | `PGjsonb`
343+type instance PG (Jsonb hask) = 'PGjsonb
344+
345+{- | The `Composite` newtype is an indication that the Haskell
346+type it's applied to should be stored as a `PGcomposite`.
347+-}
348+newtype Composite record = Composite {getComposite :: record}
349+ deriving stock (Eq, Ord, Show, Read, GHC.Generic)
350+ deriving anyclass (SOP.HasDatatypeInfo, SOP.Generic)
351+-- | `PGcomposite` @(@`RowPG` @hask)@
352+type instance PG (Composite hask) = 'PGcomposite (RowPG hask)
353+
354+{- | The `Enumerated` newtype is an indication that the Haskell
355+type it's applied to should be stored as a `PGenum`.
356+-}
357+newtype Enumerated enum = Enumerated {getEnumerated :: enum}
358+ deriving stock (Eq, Ord, Show, Read, GHC.Generic)
359+ deriving anyclass (SOP.HasDatatypeInfo, SOP.Generic)
360+-- | `PGenum` @(@`LabelsPG` @hask)@
361+type instance PG (Enumerated hask) = 'PGenum (LabelsPG hask)
362+
363+{- | The `VarArray` newtype is an indication that the Haskell
364+type it's applied to should be stored as a `PGvararray`.
365+
366+>>> :kind! PG (VarArray (Vector Double))
367+PG (VarArray (Vector Double)) :: PGType
368+= 'PGvararray ('NotNull 'PGfloat8)
369+-}
370+newtype VarArray arr = VarArray {getVarArray :: arr}
371+ deriving stock (Eq, Ord, Show, Read, GHC.Generic)
372+ deriving anyclass (SOP.HasDatatypeInfo, SOP.Generic)
373+-- | `PGvararray` @(@`NullPG` @hask)@
374+type instance PG (VarArray (Vector hask)) = 'PGvararray (NullPG hask)
375+type instance PG (VarArray [hask]) = 'PGvararray (NullPG hask)
376+
377+{- | The `FixArray` newtype is an indication that the Haskell
378+type it's applied to should be stored as a `PGfixarray`.
379+
380+>>> :kind! PG (FixArray ((Double, Double), (Double, Double)))
381+PG (FixArray ((Double, Double), (Double, Double))) :: PGType
382+= 'PGfixarray '[2, 2] ('NotNull 'PGfloat8)
383+-}
384+newtype FixArray arr = FixArray {getFixArray :: arr}
385+ deriving stock (Eq, Ord, Show, Read, GHC.Generic)
386+ deriving anyclass (SOP.HasDatatypeInfo, SOP.Generic)
387+-- | `PGfixarray` @(@`DimPG` @hask) (@`FixPG` @hask)@
388+type instance PG (FixArray hask) = 'PGfixarray (DimPG hask) (FixPG hask)
squeal-postgresql/src/Squeal/PostgreSQL/PQ.hs+454−318
@@ -5,22 +5,26 @@ Copyright: (c) Eitan Chatav, 2017
55Maintainer: eitan@morphism.tech
66Stability: experimental
77
8−`Squeal.PostgreSQL.PQ` is where Squeal statements come to actually get run by
9−`LibPQ`. It contains a `PQ` indexed monad transformer to run `Definition`s and
10−a `MonadPQ` constraint for running a `Manipulation` or `Query`.
8+This module is where Squeal commands actually get executed by
9+`Database.PostgreSQL.LibPQ`. It containts two typeclasses, `IndexedMonadTransPQ` for executing
10+a `Definition` and `MonadPQ` for executing a `Manipulation` or `Query`,
11+and a `PQ` type with instances for them.
12+
13+Using Squeal in your application will come down to defining
14+the @schemas@ of your database and including @PQ schemas schemas@ in your
15+application's monad transformer stack, giving it an instance of `MonadPQ`.
16+
17+This module also provides functions for retrieving rows from the `LibPQ.Result`
18+of executing Squeal commands.
1119-}
1220
1321{-# OPTIONS_GHC -fno-warn-redundant-constraints #-}
1422{-# LANGUAGE
15− DataKinds
16− , DefaultSignatures
23+ DefaultSignatures
1724 , FunctionalDependencies
18− , PolyKinds
19− , DeriveFunctor
2025 , FlexibleContexts
2126 , FlexibleInstances
22− , MagicHash
23− , MultiParamTypeClasses
27+ , InstanceSigs
2428 , OverloadedStrings
2529 , RankNTypes
2630 , ScopedTypeVariables
@@ -33,51 +37,57 @@ a `MonadPQ` constraint for running a `Manipulation` or `Query`.
3337
3438module Squeal.PostgreSQL.PQ
3539 ( -- * Connection
36− Connection (Connection, unConnection)
40+ LibPQ.Connection
3741 , connectdb
3842 , finish
3943 , withConnection
44+ , lowerConnection
4045 -- * PQ
41− , PQ (PQ, runPQ)
46+ , PQ (PQ, unPQ)
47+ , runPQ
4248 , execPQ
43− , pqAp
44− , pqBind
45− , pqThen
46− , define
47− , thenDefine
48− -- * MonadPQ
49+ , evalPQ
50+ , IndexedMonadTransPQ (..)
4951 , MonadPQ (..)
50− , PQRun
51− , pqliftWith
52− -- * Result
53− , Result (Result, unResult)
54− , RowNumber (RowNumber, unRowNumber)
55− , ColumnNumber (UnsafeColumnNumber, getColumnNumber)
56− , HasColumnNumber (columnNumber)
57− , getValue
52+ -- * Results
53+ , LibPQ.Result
54+ , LibPQ.Row
55+ , ntuples
5856 , getRow
5957 , getRows
60− , ntuples
6158 , nextRow
6259 , firstRow
6360 , liftResult
61+ , LibPQ.ExecStatus (..)
62+ , resultStatus
63+ , resultErrorMessage
64+ , resultErrorCode
65+ -- * Exceptions
66+ , SquealException (..)
67+ , PQState (..)
68+ , okResult
69+ , catchSqueal
70+ , handleSqueal
71+ , trySqueal
6472 ) where
6573
66−import Control.Exception.Lifted
67−import Control.Monad.Base
74+import Control.Exception (Exception, throw)
6875import Control.Monad.Except
69−import Control.Monad.Trans.Control
76+import Control.Monad.Morph
77+import UnliftIO (MonadUnliftIO (..), bracket, catch, handle, try)
7078import Data.ByteString (ByteString)
7179import Data.Foldable
7280import Data.Function ((&))
81+import Data.Functor ((<&>))
7382import Data.Kind
74−import Data.Monoid
83+import Data.Text (pack, Text)
7584import Data.Traversable
7685import Generics.SOP
77−import GHC.Exts hiding (fromList)
78−import GHC.TypeLits
86+import PostgreSQL.Binary.Encoding (encodingBytes)
7987
88+import qualified Control.Monad.Fail as Fail
8089import qualified Database.PostgreSQL.LibPQ as LibPQ
90+import qualified PostgreSQL.Binary.Encoding as Encoding
8191
8292import Squeal.PostgreSQL.Binary
8393import Squeal.PostgreSQL.Definition
@@ -90,7 +100,6 @@ import Control.Monad.Trans.Identity
90100import Control.Monad.Trans.Reader
91101import Control.Monad.Trans.Maybe
92102import Control.Monad.Trans.Cont
93−import Control.Monad.Trans.List
94103
95104import qualified Control.Monad.Trans.State.Lazy as Lazy
96105import qualified Control.Monad.Trans.State.Strict as Strict
@@ -99,10 +108,8 @@ import qualified Control.Monad.Trans.Writer.Strict as Strict
99108import qualified Control.Monad.Trans.RWS.Lazy as Lazy
100109import qualified Control.Monad.Trans.RWS.Strict as Strict
101110
102−-- | A `Connection` consists of a `Database.PostgreSQL.LibPQ`
103−-- `Database.PastgreSQL.LibPQ.Connection` and a phantom `TablesType`
104−newtype Connection (schema :: TablesType) =
105− Connection { unConnection :: LibPQ.Connection }
111+-- $setup
112+-- >>> import Squeal.PostgreSQL
106113
107114{- | Makes a new connection to the database server.
108115
@@ -119,8 +126,9 @@ backslashes within the value must be escaped with a backslash, i.e., ' and \.
119126To specify the schema you wish to connect with, use type application.
120127
121128>>> :set -XDataKinds
129+>>> :set -XPolyKinds
122130>>> :set -XTypeOperators
123−>>> type Schema = '["tab" ::: Unconstraint :=> '["col" ::: 'NoDef :=> 'Null 'PGint2]]
131+>>> type Schema = '["tab" ::: '[] :=> '["col" ::: 'NoDef :=> 'Null 'PGint2]]
124132>>> :set -XTypeApplications
125133>>> :set -XOverloadedStrings
126134>>> conn <- connectdb @Schema "host=localhost port=5432 dbname=exampledb"
@@ -129,107 +137,163 @@ Note that, for now, squeal doesn't offer any protection from connecting
129137with the wrong schema!
130138-}
131139connectdb
132− :: forall schema io
133− . MonadBase IO io
140+ :: forall schemas io
141+ . MonadIO io
134142 => ByteString -- ^ conninfo
135− -> io (Connection schema)
136−connectdb = fmap Connection . liftBase . LibPQ.connectdb
143+ -> io (K LibPQ.Connection schemas)
144+connectdb = fmap K . liftIO . LibPQ.connectdb
137145
138146-- | Closes the connection to the server.
139−finish :: MonadBase IO io => Connection schema -> io ()
140−finish = liftBase . LibPQ.finish . unConnection
147+finish :: MonadIO io => K LibPQ.Connection schemas -> io ()
148+finish = liftIO . LibPQ.finish . unK
141149
142150-- | Do `connectdb` and `finish` before and after a computation.
143151withConnection
144− :: forall schema0 schema1 io x
145− . MonadBaseControl IO io
152+ :: forall schemas0 schemas1 io x
153+ . MonadUnliftIO io
146154 => ByteString
147− -> (Connection schema0 -> io (x, Connection schema1))
155+ -> PQ schemas0 schemas1 io x
148156 -> io x
149157withConnection connString action = do
150− (x, _conn) <- bracket (connectdb connString) finish action
158+ K x <- bracket (connectdb connString) finish (unPQ action)
151159 return x
152160
161+-- | Safely `lowerConnection` to a smaller schema.
162+lowerConnection
163+ :: K LibPQ.Connection (schema ': schemas)
164+ -> K LibPQ.Connection schemas
165+lowerConnection (K conn) = K conn
166+
153167-- | We keep track of the schema via an Atkey indexed state monad transformer,
154168-- `PQ`.
155169newtype PQ
156− (schema0 :: TablesType)
157− (schema1 :: TablesType)
170+ (schemas0 :: SchemasType)
171+ (schemas1 :: SchemasType)
158172 (m :: Type -> Type)
159173 (x :: Type) =
160− PQ { runPQ :: Connection schema0 -> m (x, Connection schema1) }
161− deriving Functor
174+ PQ { unPQ :: K LibPQ.Connection schemas0 -> m (K x schemas1) }
175+
176+instance Monad m => Functor (PQ schemas0 schemas1 m) where
177+ fmap f (PQ pq) = PQ $ \ conn -> do
178+ K x <- pq conn
179+ return $ K (f x)
162180
163−-- | Run a `PQ` and discard the result but keep the `Connection`.
181+-- | Run a `PQ` and keep the result and the `LibPQ.Connection`.
182+runPQ
183+ :: Functor m
184+ => PQ schemas0 schemas1 m x
185+ -> K LibPQ.Connection schemas0
186+ -> m (x, K LibPQ.Connection schemas1)
187+runPQ (PQ pq) conn = (\ x -> (unK x, K (unK conn))) <$> pq conn
188+ -- K x <- pq conn
189+ -- return (x, K (unK conn))
190+
191+-- | Execute a `PQ` and discard the result but keep the `LibPQ.Connection`.
164192execPQ
165193 :: Functor m
166− => PQ schema0 schema1 m x
167− -> Connection schema0
168− -> m (Connection schema1)
169−execPQ (PQ pq) = fmap snd . pq
170−
171−-- | indexed analog of `<*>`
172−pqAp
173− :: Monad m
174− => PQ schema0 schema1 m (x -> y)
175− -> PQ schema1 schema2 m x
176− -> PQ schema0 schema2 m y
177−pqAp (PQ f) (PQ x) = PQ $ \ conn -> do
178− (f', conn') <- f conn
179− (x', conn'') <- x conn'
180− return (f' x', conn'')
181−
182−-- | indexed analog of `=<<`
183−pqBind
184− :: Monad m
185− => (x -> PQ schema1 schema2 m y)
186− -> PQ schema0 schema1 m x
187− -> PQ schema0 schema2 m y
188−pqBind f (PQ x) = PQ $ \ conn -> do
189− (x', conn') <- x conn
190− runPQ (f x') conn'
191−
192−-- | indexed analog of flipped `>>`
193−pqThen
194− :: Monad m
195− => PQ schema1 schema2 m y
196− -> PQ schema0 schema1 m x
197− -> PQ schema0 schema2 m y
198−pqThen pq2 pq1 = pq1 & pqBind (\ _ -> pq2)
199−
200−-- | Run a `Definition` with `LibPQ.exec`, we expect that libpq obeys the law
201−--
202−-- @define statement1 & thenDefine statement2 = define (statement1 >>> statement2)@
203−define
204− :: MonadBase IO io
205− => Definition schema0 schema1
206− -> PQ schema0 schema1 io (Result '[])
207−define (UnsafeDefinition q) = PQ $ \ (Connection conn) -> do
208− resultMaybe <- liftBase $ LibPQ.exec conn q
209− case resultMaybe of
210− Nothing -> error
211− "define: LibPQ.exec returned no results"
212− Just result -> return (Result result, Connection conn)
213−
214−-- | Chain together `define` actions.
215−thenDefine
216− :: MonadBase IO io
217− => Definition schema1 schema2
218− -> PQ schema0 schema1 io x
219− -> PQ schema0 schema2 io (Result '[])
220−thenDefine = pqThen . define
221−
222−{- | `MonadPQ` is an `mtl` style constraint, similar to
223−`Control.Monad.State.Class.MonadState`, for using `LibPQ` to
194+ => PQ schemas0 schemas1 m x
195+ -> K LibPQ.Connection schemas0
196+ -> m (K LibPQ.Connection schemas1)
197+execPQ (PQ pq) conn = mapKK (\ _ -> unK conn) <$> pq conn
198+
199+-- | Evaluate a `PQ` and discard the `LibPQ.Connection` but keep the result.
200+evalPQ
201+ :: Functor m
202+ => PQ schemas0 schemas1 m x
203+ -> K LibPQ.Connection schemas0
204+ -> m x
205+evalPQ (PQ pq) conn = unK <$> pq conn
206+
207+-- | An [Atkey indexed monad](https://bentnib.org/paramnotions-jfp.pdf) is a `Functor`
208+-- [enriched category](https://ncatlab.org/nlab/show/enriched+category).
209+-- An indexed monad transformer transforms a `Monad` into an indexed monad.
210+-- And, `IndexedMonadTransPQ` is a class for indexed monad transformers that
211+-- support running `Definition`s using `define`.
212+class IndexedMonadTransPQ pq where
213+
214+ -- | indexed analog of `<*>`
215+ pqAp
216+ :: Monad m
217+ => pq schemas0 schemas1 m (x -> y)
218+ -> pq schemas1 schemas2 m x
219+ -> pq schemas0 schemas2 m y
220+
221+ -- | indexed analog of `join`
222+ pqJoin
223+ :: Monad m
224+ => pq schemas0 schemas1 m (pq schemas1 schemas2 m y)
225+ -> pq schemas0 schemas2 m y
226+ pqJoin pq = pq & pqBind id
227+
228+ -- | indexed analog of `=<<`
229+ pqBind
230+ :: Monad m
231+ => (x -> pq schemas1 schemas2 m y)
232+ -> pq schemas0 schemas1 m x
233+ -> pq schemas0 schemas2 m y
234+
235+ -- | indexed analog of flipped `>>`
236+ pqThen
237+ :: Monad m
238+ => pq schemas1 schemas2 m y
239+ -> pq schemas0 schemas1 m x
240+ -> pq schemas0 schemas2 m y
241+ pqThen pq2 pq1 = pq1 & pqBind (\ _ -> pq2)
242+
243+ -- | indexed analog of `<=<`
244+ pqAndThen
245+ :: Monad m
246+ => (y -> pq schemas1 schemas2 m z)
247+ -> (x -> pq schemas0 schemas1 m y)
248+ -> x -> pq schemas0 schemas2 m z
249+ pqAndThen g f x = pqBind g (f x)
250+
251+ -- | Run a `Definition` with `LibPQ.exec`.
252+ --
253+ -- It should be functorial in effect.
254+ --
255+ -- @define id = return ()@
256+ -- @define (statement1 >>> statement2) = define statement1 & pqThen (define statement2)@
257+ define
258+ :: MonadIO io
259+ => Definition schemas0 schemas1
260+ -> pq schemas0 schemas1 io ()
261+
262+instance IndexedMonadTransPQ PQ where
263+
264+ pqAp (PQ f) (PQ x) = PQ $ \ conn -> do
265+ K f' <- f conn
266+ K x' <- x (K (unK conn))
267+ return $ K (f' x')
268+
269+ pqBind f (PQ x) = PQ $ \ conn -> do
270+ K x' <- x conn
271+ unPQ (f x') (K (unK conn))
272+
273+ define (UnsafeDefinition q) = PQ $ \ (K conn) -> do
274+ resultMaybe <- liftIO $ LibPQ.exec conn q
275+ case resultMaybe of
276+ Nothing -> throw $ ResultException
277+ "define: LibPQ.exec returned no results"
278+ Just result -> K <$> okResult_ result
279+
280+{- | `MonadPQ` is an @mtl@ style constraint, similar to
281+`Control.Monad.State.Class.MonadState`, for using `Database.PostgreSQL.LibPQ` to
224282
225283* `manipulateParams` runs a `Manipulation` with params from a type
226284 with a `ToParams` constraint. It calls `LibPQ.execParams` and
227285 doesn't afraid of anything.
228286
287+* `manipulateParams_` is like `manipulateParams` for a returning-free statement.
288+
229289* `manipulate` is like `manipulateParams` for a parameter-free statement.
230290
291+* `manipulate_` is like `manipulate` for a returning-free statement.
292+
231293* `runQueryParams` is like `manipulateParams` for query statements.
232294
295+* `runQuery` is like `runQueryParams` for a parameter-free statement.
296+
233297* `traversePrepared` has the same type signature as a composition of
234298 `traverse` and `manipulateParams` but provides an optimization by
235299 preparing the statement with `LibPQ.prepare` and then traversing a
@@ -239,11 +303,11 @@ thenDefine = pqThen . define
239303* `forPrepared` is a flipped `traversePrepared`
240304
241305* `traversePrepared_` is like `traversePrepared` but works on `Foldable`
242− containers and returns unit.
306+ containers for a returning-free statement.
243307
244308* `forPrepared_` is a flipped `traversePrepared_`.
245309
246−* `liftPQ` lets you lift actions from `LibPQ` that require a connection
310+* `liftPQ` lets you lift actions from `Database.PostgreSQL.LibPQ` that require a connection
247311 into your monad.
248312
249313To define an instance, you can minimally define only `manipulateParams`,
@@ -251,326 +315,398 @@ To define an instance, you can minimally define only `manipulateParams`,
251315a default instance.
252316
253317-}
254−class Monad pq => MonadPQ schema pq | pq -> schema where
318+class Monad pq => MonadPQ schemas pq | pq -> schemas where
255319 manipulateParams
256− :: ToParams x params
257− => Manipulation schema params ys
320+ :: (ToParams x params, All OidOfParam params)
321+ => Manipulation '[] schemas params ys
258322 -- ^ `insertInto`, `update` or `deleteFrom`
259− -> x -> pq (Result ys)
323+ -> x -> pq (K LibPQ.Result ys)
260324 default manipulateParams
261− :: (MonadTrans t, MonadPQ schema pq1, pq ~ t pq1)
262− => ToParams x params
263− => Manipulation schema params ys
325+ :: (MonadTrans t, MonadPQ schemas pq1, pq ~ t pq1)
326+ => (ToParams x params, All OidOfParam params)
327+ => Manipulation '[] schemas params ys
264328 -- ^ `insertInto`, `update` or `deleteFrom`
265− -> x -> pq (Result ys)
329+ -> x -> pq (K LibPQ.Result ys)
266330 manipulateParams manipulation params = lift $
267331 manipulateParams manipulation params
268332
269− manipulate :: Manipulation schema '[] ys -> pq (Result ys)
333+ manipulateParams_
334+ :: (ToParams x params, All OidOfParam params)
335+ => Manipulation '[] schemas params '[]
336+ -- ^ `insertInto`, `update` or `deleteFrom`
337+ -> x -> pq ()
338+ manipulateParams_ q x = void $ manipulateParams q x
339+
340+ manipulate :: Manipulation '[] schemas '[] ys -> pq (K LibPQ.Result ys)
270341 manipulate statement = manipulateParams statement ()
271342
343+ manipulate_ :: Manipulation '[] schemas '[] '[] -> pq ()
344+ manipulate_ = void . manipulate
345+
272346 runQueryParams
273− :: ToParams x params
274− => Query schema params ys
347+ :: (ToParams x params, All OidOfParam params)
348+ => Query '[] '[] schemas params ys
275349 -- ^ `select` and friends
276− -> x -> pq (Result ys)
350+ -> x -> pq (K LibPQ.Result ys)
277351 runQueryParams = manipulateParams . queryStatement
278352
279353 runQuery
280− :: Query schema '[] ys
354+ :: Query '[] '[] schemas '[] ys
281355 -- ^ `select` and friends
282− -> pq (Result ys)
356+ -> pq (K LibPQ.Result ys)
283357 runQuery q = runQueryParams q ()
284358
285359 traversePrepared
286− :: (ToParams x params, Traversable list)
287− => Manipulation schema params ys
288− -- ^ `insertInto`, `update` or `deleteFrom`
289− -> list x -> pq (list (Result ys))
360+ :: (ToParams x params, Traversable list, All OidOfParam params)
361+ => Manipulation '[] schemas params ys
362+ -- ^ `insertInto`, `update`, or `deleteFrom`, and friends
363+ -> list x -> pq (list (K LibPQ.Result ys))
290364 default traversePrepared
291− :: (MonadTrans t, MonadPQ schema pq1, pq ~ t pq1)
292− => (ToParams x params, Traversable list)
293− => Manipulation schema params ys -> list x -> pq (list (Result ys))
365+ :: (MonadTrans t, MonadPQ schemas pq1, pq ~ t pq1)
366+ => (ToParams x params, Traversable list, All OidOfParam params)
367+ => Manipulation '[] schemas params ys -> list x -> pq (list (K LibPQ.Result ys))
294368 traversePrepared manipulation params = lift $
295369 traversePrepared manipulation params
296370
297371 forPrepared
298− :: (ToParams x params, Traversable list)
372+ :: (ToParams x params, Traversable list, All OidOfParam params)
299373 => list x
300− -> Manipulation schema params ys
374+ -> Manipulation '[] schemas params ys
301375 -- ^ `insertInto`, `update` or `deleteFrom`
302− -> pq (list (Result ys))
376+ -> pq (list (K LibPQ.Result ys))
303377 forPrepared = flip traversePrepared
304378
305379 traversePrepared_
306− :: (ToParams x params, Foldable list)
307− => Manipulation schema params '[]
380+ :: (ToParams x params, Foldable list, All OidOfParam params)
381+ => Manipulation '[] schemas params '[]
308382 -- ^ `insertInto`, `update` or `deleteFrom`
309383 -> list x -> pq ()
310384 default traversePrepared_
311− :: (MonadTrans t, MonadPQ schema pq1, pq ~ t pq1)
312− => (ToParams x params, Foldable list)
313− => Manipulation schema params '[]
385+ :: (MonadTrans t, MonadPQ schemas pq1, pq ~ t pq1)
386+ => (ToParams x params, Foldable list, All OidOfParam params)
387+ => Manipulation '[] schemas params '[]
314388 -- ^ `insertInto`, `update` or `deleteFrom`
315389 -> list x -> pq ()
316390 traversePrepared_ manipulation params = lift $
317391 traversePrepared_ manipulation params
318392
319393 forPrepared_
320− :: (ToParams x params, Foldable list)
394+ :: (ToParams x params, Foldable list, All OidOfParam params)
321395 => list x
322− -> Manipulation schema params '[]
396+ -> Manipulation '[] schemas params '[]
323397 -- ^ `insertInto`, `update` or `deleteFrom`
324398 -> pq ()
325399 forPrepared_ = flip traversePrepared_
326400
327401 liftPQ :: (LibPQ.Connection -> IO a) -> pq a
328402 default liftPQ
329− :: (MonadTrans t, MonadPQ schema pq1, pq ~ t pq1)
403+ :: (MonadTrans t, MonadPQ schemas pq1, pq ~ t pq1)
330404 => (LibPQ.Connection -> IO a) -> pq a
331405 liftPQ = lift . liftPQ
332406
333−instance MonadBase IO io => MonadPQ schema (PQ schema schema io) where
407+instance (MonadIO io, schemas0 ~ schemas, schemas1 ~ schemas)
408+ => MonadPQ schemas (PQ schemas0 schemas1 io) where
334409
335410 manipulateParams
336− (UnsafeManipulation q :: Manipulation schema ps ys) (params :: x) =
337− PQ $ \ (Connection conn) -> do
411+ (UnsafeManipulation q :: Manipulation '[] schemas ps ys) (params :: x) =
412+ PQ $ \ (K conn) -> do
338413 let
339− toParam' bytes = (LibPQ.invalidOid,bytes,LibPQ.Binary)
340− params' = fmap (fmap toParam') (hcollapse (toParams @x @ps params))
341− resultMaybe <- liftBase $ LibPQ.execParams conn q params' LibPQ.Binary
414+ paramSet
415+ :: forall param. OidOfParam param
416+ => K (Maybe Encoding.Encoding) param
417+ -> K (Maybe (LibPQ.Oid, ByteString, LibPQ.Format)) param
418+ paramSet (K maybeEncoding) = K $
419+ maybeEncoding <&> \encoding ->
420+ (oidOfParam @param, encodingBytes encoding, LibPQ.Binary)
421+ params'
422+ = hcollapse
423+ . hcmap (Proxy @OidOfParam) paramSet
424+ $ toParams @x @ps params
425+ q' = q <> ";"
426+ resultMaybe <- liftIO $ LibPQ.execParams conn q' params' LibPQ.Binary
342427 case resultMaybe of
343− Nothing -> error
428+ Nothing -> throw $ ResultException
344429 "manipulateParams: LibPQ.execParams returned no results"
345− Just result -> return (Result result, Connection conn)
430+ Just result -> do
431+ okResult_ result
432+ return $ K (K result)
346433
347434 traversePrepared
348− (UnsafeManipulation q :: Manipulation schema xs ys) (list :: list x) =
349− PQ $ \ (Connection conn) -> liftBase $ do
350− let temp = "temporary_statement"
351− prepResultMaybe <- LibPQ.prepare conn temp q Nothing
435+ (UnsafeManipulation q :: Manipulation '[] schemas xs ys) (list :: list x) =
436+ PQ $ \ (K conn) -> liftIO $ do
437+ let
438+ temp = "temporary_statement"
439+ paramOid :: forall p. OidOfParam p => K LibPQ.Oid p
440+ paramOid = K (oidOfParam @p)
441+ paramOids :: NP (K LibPQ.Oid) xs
442+ paramOids = hcpure (Proxy @OidOfParam) paramOid
443+ paramOids' :: [LibPQ.Oid]
444+ paramOids' = hcollapse paramOids
445+ prepResultMaybe <- LibPQ.prepare conn temp q (Just paramOids')
352446 case prepResultMaybe of
353− Nothing -> error
447+ Nothing -> throw $ ResultException
354448 "traversePrepared: LibPQ.prepare returned no results"
355− Just prepResult -> do
356− status <- LibPQ.resultStatus prepResult
357− unless (status == LibPQ.CommandOk) . error $
358− "traversePrepared: LibPQ.prepare status " <> show status
449+ Just prepResult -> okResult_ prepResult
359450 results <- for list $ \ params -> do
360451 let
361− toParam' bytes = (bytes,LibPQ.Binary)
452+ toParam' encoding = (encodingBytes encoding, LibPQ.Binary)
362453 params' = fmap (fmap toParam') (hcollapse (toParams @x @xs params))
363454 resultMaybe <- LibPQ.execPrepared conn temp params' LibPQ.Binary
364455 case resultMaybe of
365− Nothing -> error
456+ Nothing -> throw $ ResultException
366457 "traversePrepared: LibPQ.execParams returned no results"
367− Just result -> return $ Result result
458+ Just result -> do
459+ okResult_ result
460+ return $ K result
368461 deallocResultMaybe <- LibPQ.exec conn ("DEALLOCATE " <> temp <> ";")
369462 case deallocResultMaybe of
370− Nothing -> error
463+ Nothing -> throw $ ResultException
371464 "traversePrepared: LibPQ.exec DEALLOCATE returned no results"
372− Just deallocResult -> do
373− status <- LibPQ.resultStatus deallocResult
374− unless (status == LibPQ.CommandOk) . error $
375− "traversePrepared: DEALLOCATE status " <> show status
376− return (results, Connection conn)
465+ Just deallocResult -> okResult_ deallocResult
466+ return (K results)
377467
378468 traversePrepared_
379− (UnsafeManipulation q :: Manipulation schema xs '[]) (list :: list x) =
380− PQ $ \ (Connection conn) -> liftBase $ do
381− let temp = "temporary_statement"
382− prepResultMaybe <- LibPQ.prepare conn temp q Nothing
469+ (UnsafeManipulation q :: Manipulation '[] schemas xs '[]) (list :: list x) =
470+ PQ $ \ (K conn) -> liftIO $ do
471+ let
472+ temp = "temporary_statement"
473+ paramOid :: forall p. OidOfParam p => K LibPQ.Oid p
474+ paramOid = K (oidOfParam @p)
475+ paramOids :: NP (K LibPQ.Oid) xs
476+ paramOids = hcpure (Proxy @OidOfParam) paramOid
477+ paramOids' :: [LibPQ.Oid]
478+ paramOids' = hcollapse paramOids
479+ prepResultMaybe <- LibPQ.prepare conn temp q (Just paramOids')
383480 case prepResultMaybe of
384− Nothing -> error
481+ Nothing -> throw $ ResultException
385482 "traversePrepared_: LibPQ.prepare returned no results"
386− Just prepResult -> do
387− status <- LibPQ.resultStatus prepResult
388− unless (status == LibPQ.CommandOk) . error $
389− "traversePrepared: LibPQ.prepare status " <> show status
483+ Just prepResult -> okResult_ prepResult
390484 for_ list $ \ params -> do
391485 let
392− toParam' bytes = (bytes,LibPQ.Binary)
486+ toParam' encoding = (encodingBytes encoding, LibPQ.Binary)
393487 params' = fmap (fmap toParam') (hcollapse (toParams @x @xs params))
394488 resultMaybe <- LibPQ.execPrepared conn temp params' LibPQ.Binary
395489 case resultMaybe of
396− Nothing -> error
490+ Nothing -> throw $ ResultException
397491 "traversePrepared_: LibPQ.execParams returned no results"
398− Just _result -> return ()
492+ Just result -> okResult_ result
399493 deallocResultMaybe <- LibPQ.exec conn ("DEALLOCATE " <> temp <> ";")
400494 case deallocResultMaybe of
401− Nothing -> error
495+ Nothing -> throw $ ResultException
402496 "traversePrepared: LibPQ.exec DEALLOCATE returned no results"
403− Just deallocResult -> do
404− status <- LibPQ.resultStatus deallocResult
405− unless (status == LibPQ.CommandOk) . error $
406− "traversePrepared: DEALLOCATE status " <> show status
407− return ((), Connection conn)
408−
409− liftPQ pq = PQ $ \ (Connection conn) -> do
410− y <- liftBase $ pq conn
411− return (y, Connection conn)
412−
413−instance MonadPQ schema m => MonadPQ schema (IdentityT m)
414−instance MonadPQ schema m => MonadPQ schema (ReaderT r m)
415−instance MonadPQ schema m => MonadPQ schema (Strict.StateT s m)
416−instance MonadPQ schema m => MonadPQ schema (Lazy.StateT s m)
417−instance (Monoid w, MonadPQ schema m) => MonadPQ schema (Strict.WriterT w m)
418−instance (Monoid w, MonadPQ schema m) => MonadPQ schema (Lazy.WriterT w m)
419−instance MonadPQ schema m => MonadPQ schema (MaybeT m)
420−instance MonadPQ schema m => MonadPQ schema (ExceptT e m)
421−instance (Monoid w, MonadPQ schema m) => MonadPQ schema (Strict.RWST r w s m)
422−instance (Monoid w, MonadPQ schema m) => MonadPQ schema (Lazy.RWST r w s m)
423−instance MonadPQ schema m => MonadPQ schema (ContT r m)
424−instance MonadPQ schema m => MonadPQ schema (ListT m)
425−
426−instance Monad m => Applicative (PQ schema schema m) where
427− pure x = PQ $ \ conn -> pure (x, conn)
497+ Just deallocResult -> okResult_ deallocResult
498+ return (K ())
499+
500+ liftPQ pq = PQ $ \ (K conn) -> do
501+ y <- liftIO $ pq conn
502+ return (K y)
503+
504+instance MonadPQ schemas m => MonadPQ schemas (IdentityT m)
505+instance MonadPQ schemas m => MonadPQ schemas (ReaderT r m)
506+instance MonadPQ schemas m => MonadPQ schemas (Strict.StateT s m)
507+instance MonadPQ schemas m => MonadPQ schemas (Lazy.StateT s m)
508+instance (Monoid w, MonadPQ schemas m) => MonadPQ schemas (Strict.WriterT w m)
509+instance (Monoid w, MonadPQ schemas m) => MonadPQ schemas (Lazy.WriterT w m)
510+instance MonadPQ schemas m => MonadPQ schemas (MaybeT m)
511+instance MonadPQ schemas m => MonadPQ schemas (ExceptT e m)
512+instance (Monoid w, MonadPQ schemas m) => MonadPQ schemas (Strict.RWST r w s m)
513+instance (Monoid w, MonadPQ schemas m) => MonadPQ schemas (Lazy.RWST r w s m)
514+instance MonadPQ schemas m => MonadPQ schemas (ContT r m)
515+
516+instance (Monad m, schemas0 ~ schemas1)
517+ => Applicative (PQ schemas0 schemas1 m) where
518+ pure x = PQ $ \ _conn -> pure (K x)
428519 (<*>) = pqAp
429520
430−instance Monad m => Monad (PQ schema schema m) where
521+instance (Monad m, schemas0 ~ schemas1)
522+ => Monad (PQ schemas0 schemas1 m) where
431523 return = pure
432524 (>>=) = flip pqBind
433525
434−instance MonadTrans (PQ schema schema) where
435− lift m = PQ $ \ conn -> do
526+instance (Monad m, schemas0 ~ schemas1)
527+ => Fail.MonadFail (PQ schemas0 schemas1 m) where
528+ fail = Fail.fail
529+
530+instance schemas0 ~ schemas1 => MFunctor (PQ schemas0 schemas1) where
531+ hoist f (PQ pq) = PQ (f . pq)
532+
533+instance schemas0 ~ schemas1 => MonadTrans (PQ schemas0 schemas1) where
534+ lift m = PQ $ \ _conn -> do
436535 x <- m
437− return (x, conn)
438−
439−instance MonadBase b m => MonadBase b (PQ schema schema m) where
440− liftBase = lift . liftBase
441−
442−-- | A snapshot of the state of a `PQ` computation.
443−type PQRun schema =
444− forall m x. Monad m => PQ schema schema m x -> m (x, Connection schema)
445−
446−-- | Helper function in defining `MonadBaseControl` instance for `PQ`.
447−pqliftWith :: Functor m => (PQRun schema -> m a) -> PQ schema schema m a
448−pqliftWith f = PQ $ \ conn ->
449− fmap (\ x -> (x, conn)) (f $ \ pq -> runPQ pq conn)
450−
451−instance MonadBaseControl b m => MonadBaseControl b (PQ schema schema m) where
452− type StM (PQ schema schema m) x = StM m (x, Connection schema)
453− liftBaseWith f =
454− pqliftWith $ \ run -> liftBaseWith $ \ runInBase -> f $ runInBase . run
455− restoreM = PQ . const . restoreM
456−
457−-- | Encapsulates the result of a squeal command run by @LibPQ@.
458−-- `Result`s are parameterized by a `ColumnsType` describing the column names
459−-- and their types.
460−newtype Result (columns :: RelationType)
461− = Result { unResult :: LibPQ.Result }
462−
463−-- | Just newtypes around a `CInt`
464−newtype RowNumber = RowNumber { unRowNumber :: LibPQ.Row }
465−
466−-- | In addition to being newtypes around a `CInt`, a `ColumnNumber` is
467−-- parameterized by a `Nat`ural number and acts as an index into a row.
468−newtype ColumnNumber (n :: Nat) (cs :: [k]) (c :: k) =
469− UnsafeColumnNumber { getColumnNumber :: LibPQ.Column }
470−
471−-- | >>> getColumnNumber (columnNumber @5 @'[_,_,_,_,_,_])
472−-- Col 5
473−class KnownNat n => HasColumnNumber n columns column
474− | n columns -> column where
475− columnNumber :: ColumnNumber n columns column
476− columnNumber =
477− UnsafeColumnNumber . fromIntegral $ natVal' (proxy# :: Proxy# n)
478−instance {-# OVERLAPPING #-} HasColumnNumber 0 (column1:columns) column1
479−instance {-# OVERLAPPABLE #-}
480− (KnownNat n, HasColumnNumber (n-1) columns column)
481− => HasColumnNumber n (column' : columns) column
482−
483−-- | Get a single value corresponding to a given row and column number
484−-- from a `Result`.
485−getValue
486− :: (FromColumnValue colty y, MonadBase IO io)
487− => RowNumber -- ^ row
488− -> ColumnNumber n columns colty -- ^ col
489− -> Result columns -- ^ result
490− -> io y
491−getValue
492− (RowNumber r)
493− (UnsafeColumnNumber c :: ColumnNumber n columns colty)
494− (Result result)
495− = fmap (fromColumnValue @colty . K) $ liftBase $ do
496− numRows <- LibPQ.ntuples result
497− when (numRows < r) $ error $
498− "getValue: expected at least " <> show r <> "rows but only saw "
499− <> show numRows
500− LibPQ.getvalue result r c
501−
502−-- | Get a row corresponding to a given row number from a `Result`.
536+ return (K x)
537+
538+instance schemas0 ~ schemas1 => MMonad (PQ schemas0 schemas1) where
539+ embed f (PQ pq) = PQ $ \ conn -> do
540+ evalPQ (f (pq conn)) conn
541+
542+instance (MonadIO m, schema0 ~ schema1)
543+ => MonadIO (PQ schema0 schema1 m) where
544+ liftIO = lift . liftIO
545+
546+instance (MonadUnliftIO m, schemas0 ~ schemas1)
547+ => MonadUnliftIO (PQ schemas0 schemas1 m) where
548+ withRunInIO
549+ :: ((forall a . PQ schemas0 schema1 m a -> IO a) -> IO b)
550+ -> PQ schemas0 schema1 m b
551+ withRunInIO inner = PQ $ \conn ->
552+ withRunInIO $ \(run :: (forall x . m x -> IO x)) ->
553+ K <$> inner (\pq -> run $ unK <$> unPQ pq conn)
554+
555+-- | Get a row corresponding to a given row number from a `LibPQ.Result`,
556+-- throwing an exception if the row number is out of bounds.
503557getRow
504− :: (FromRow columns y, MonadBase IO io)
505− => RowNumber
506− -- ^ row
507− -> Result columns
558+ :: (FromRow columns y, MonadIO io)
559+ => LibPQ.Row
560+ -- ^ row number
561+ -> K LibPQ.Result columns
508562 -- ^ result
509563 -> io y
510−getRow (RowNumber r) (Result result :: Result columns) = liftBase $ do
564+getRow r (K result :: K LibPQ.Result columns) = liftIO $ do
511565 numRows <- LibPQ.ntuples result
512− when (numRows < r) $ error $
513− "getRow: expected at least " <> show r <> "rows but only saw "
514− <> show numRows
566+ when (numRows < r) $ throw $ ResultException $
567+ "getRow: expected at least " <> pack (show r) <> "rows but only saw "
568+ <> pack (show numRows)
515569 let len = fromIntegral (lengthSList (Proxy @columns))
516570 row' <- traverse (LibPQ.getvalue result r) [0 .. len - 1]
517571 case fromList row' of
518− Nothing -> error "getRow: found unexpected length"
519− Just row -> return $ fromRow @columns row
520−
521−-- | Returns the number of rows (tuples) in the query result.
522−ntuples :: MonadBase IO io => Result columns -> io RowNumber
523−ntuples (Result result) = liftBase $ RowNumber <$> LibPQ.ntuples result
572+ Nothing -> throw $ ResultException "getRow: found unexpected length"
573+ Just row -> case fromRow @columns row of
574+ Left parseError -> throw $ ParseException $ "getRow: " <> parseError
575+ Right y -> return y
524576
525577-- | Intended to be used for unfolding in streaming libraries, `nextRow`
526578-- takes a total number of rows (which can be found with `ntuples`)
527−-- and a `Result` and given a row number if it's too large returns `Nothing`,
579+-- and a `LibPQ.Result` and given a row number if it's too large returns `Nothing`,
528580-- otherwise returning the row along with the next row number.
529581nextRow
530− :: (FromRow columns y, MonadBase IO io)
531− => RowNumber -- ^ total number of rows
532− -> Result columns -- ^ result
533− -> RowNumber -- ^ row number
534− -> io (Maybe (RowNumber,y))
535−nextRow (RowNumber total) (Result result :: Result columns) (RowNumber r)
536− = liftBase $ if r >= total then return Nothing else do
582+ :: (FromRow columns y, MonadIO io)
583+ => LibPQ.Row -- ^ total number of rows
584+ -> K LibPQ.Result columns -- ^ result
585+ -> LibPQ.Row -- ^ row number
586+ -> io (Maybe (LibPQ.Row,y))
587+nextRow total (K result :: K LibPQ.Result columns) r
588+ = liftIO $ if r >= total then return Nothing else do
537589 let len = fromIntegral (lengthSList (Proxy @columns))
538590 row' <- traverse (LibPQ.getvalue result r) [0 .. len - 1]
539591 case fromList row' of
540− Nothing -> error "nextRow: found unexpected length"
541− Just row -> return $ Just (RowNumber (r+1), fromRow @columns row)
592+ Nothing -> throw $ ResultException "nextRow: found unexpected length"
593+ Just row -> case fromRow @columns row of
594+ Left parseError -> throw $ ParseException $ "nextRow: " <> parseError
595+ Right y -> return $ Just (r+1, y)
542596
543−-- | Get all rows from a `Result`.
597+-- | Get all rows from a `LibPQ.Result`.
544598getRows
545− :: (FromRow columns y, MonadBase IO io)
546− => Result columns -- ^ result
599+ :: (FromRow columns y, MonadIO io)
600+ => K LibPQ.Result columns -- ^ result
547601 -> io [y]
548−getRows (Result result :: Result columns) = liftBase $ do
602+getRows (K result :: K LibPQ.Result columns) = liftIO $ do
549603 let len = fromIntegral (lengthSList (Proxy @columns))
550604 numRows <- LibPQ.ntuples result
551605 for [0 .. numRows - 1] $ \ r -> do
552606 row' <- traverse (LibPQ.getvalue result r) [0 .. len - 1]
553607 case fromList row' of
554− Nothing -> error "getRows: found unexpected length"
555− Just row -> return $ fromRow @columns row
608+ Nothing -> throw $ ResultException "getRows: found unexpected length"
609+ Just row -> case fromRow @columns row of
610+ Left parseError -> throw $ ParseException $ "getRows: " <> parseError
611+ Right y -> return y
556612
557−-- | Get the first row if possible from a `Result`.
613+-- | Get the first row if possible from a `LibPQ.Result`.
558614firstRow
559− :: (FromRow columns y, MonadBase IO io)
560− => Result columns -- ^ result
615+ :: (FromRow columns y, MonadIO io)
616+ => K LibPQ.Result columns -- ^ result
561617 -> io (Maybe y)
562−firstRow (Result result :: Result columns) = liftBase $ do
618+firstRow (K result :: K LibPQ.Result columns) = liftIO $ do
563619 numRows <- LibPQ.ntuples result
564620 if numRows <= 0 then return Nothing else do
565621 let len = fromIntegral (lengthSList (Proxy @columns))
566622 row' <- traverse (LibPQ.getvalue result 0) [0 .. len - 1]
567623 case fromList row' of
568− Nothing -> error "firstRow: found unexpected length"
569− Just row -> return . Just $ fromRow @columns row
624+ Nothing -> throw $ ResultException "firstRow: found unexpected length"
625+ Just row -> case fromRow @columns row of
626+ Left parseError -> throw $ ParseException $ "firstRow: " <> parseError
627+ Right y -> return $ Just y
570628
571−-- | Lifts actions on results from `LibPQ`.
629+-- | Lifts actions on results from @LibPQ@.
572630liftResult
573− :: MonadBase IO io
631+ :: MonadIO io
574632 => (LibPQ.Result -> IO x)
575− -> Result results -> io x
576−liftResult f (Result result) = liftBase $ f result
633+ -> K LibPQ.Result results -> io x
634+liftResult f (K result) = liftIO $ f result
635+
636+-- | Returns the number of rows (tuples) in the query result.
637+ntuples :: MonadIO io => K LibPQ.Result columns -> io LibPQ.Row
638+ntuples = liftResult LibPQ.ntuples
639+
640+-- | Returns the result status of the command.
641+resultStatus :: MonadIO io => K LibPQ.Result results -> io LibPQ.ExecStatus
642+resultStatus = liftResult LibPQ.resultStatus
643+
644+-- | Returns the error message most recently generated by an operation
645+-- on the connection.
646+resultErrorMessage
647+ :: MonadIO io => K LibPQ.Result results -> io (Maybe ByteString)
648+resultErrorMessage = liftResult LibPQ.resultErrorMessage
649+
650+-- | Returns the error code most recently generated by an operation
651+-- on the connection.
652+--
653+-- https://www.postgresql.org/docs/current/static/errcodes-appendix.html
654+resultErrorCode
655+ :: MonadIO io
656+ => K LibPQ.Result results
657+ -> io (Maybe ByteString)
658+resultErrorCode = liftResult (flip LibPQ.resultErrorField LibPQ.DiagSqlstate)
659+
660+-- | the state of LibPQ
661+data PQState = PQState
662+ { sqlExecStatus :: LibPQ.ExecStatus
663+ , sqlStateCode :: Maybe ByteString
664+ -- ^ https://www.postgresql.org/docs/current/static/errcodes-appendix.html
665+ , sqlErrorMessage :: Maybe ByteString
666+ } deriving (Eq, Show)
667+
668+-- | `Exception`s that can be thrown by Squeal.
669+data SquealException
670+ = PQException PQState
671+ | ResultException Text
672+ | ParseException Text
673+ deriving (Eq, Show)
674+instance Exception SquealException
675+
676+okResult_ :: MonadIO io => LibPQ.Result -> io ()
677+okResult_ result = liftIO $ do
678+ status <- LibPQ.resultStatus result
679+ case status of
680+ LibPQ.CommandOk -> return ()
681+ LibPQ.TuplesOk -> return ()
682+ _ -> do
683+ stateCode <- LibPQ.resultErrorField result LibPQ.DiagSqlstate
684+ msg <- LibPQ.resultErrorMessage result
685+ throw . PQException $ PQState status stateCode msg
686+
687+-- | Check if a `LibPQ.Result`'s status is either `LibPQ.CommandOk`
688+-- or `LibPQ.TuplesOk` otherwise `throw` a `PQException`.
689+okResult :: MonadIO io => K LibPQ.Result row -> io ()
690+okResult = okResult_ . unK
691+
692+-- | Catch `SquealException`s.
693+catchSqueal
694+ :: MonadUnliftIO io
695+ => io a
696+ -> (SquealException -> io a) -- ^ handler
697+ -> io a
698+catchSqueal = catch
699+
700+-- | Handle `SquealException`s.
701+handleSqueal
702+ :: MonadUnliftIO io
703+ => (SquealException -> io a) -- ^ handler
704+ -> io a -> io a
705+handleSqueal = handle
706+
707+-- | `Either` return a `SquealException` or a result.
708+trySqueal
709+ :: MonadUnliftIO io
710+ => io a
711+ -> io (Either SquealException a)
712+trySqueal = try
squeal-postgresql/src/Squeal/PostgreSQL/Pool.hsnew file+122
@@ -0,0 +1,122 @@
1+{-|
2+Module: Squeal.PostgreSQL.Pool
3+Description: Connection pools
4+Copyright: (c) Eitan Chatav, 2017
5+Maintainer: eitan@morphism.tech
6+Stability: experimental
7+
8+Connection pools.
9+
10+Typical use case would be to create your pool using `createConnectionPool`
11+and run anything that requires the pool connection with `usingConnectionPool`.
12+
13+Here's a simplified example:
14+
15+>>> import Squeal.PostgreSQL
16+
17+>>> :{
18+do
19+ let
20+ query :: Query_ (Public '[]) () (Only Char)
21+ query = values_ (literal 'a' `as` #fromOnly)
22+ pool <- createConnectionPool "host=localhost port=5432 dbname=exampledb" 1 0.5 10
23+ chr <- usingConnectionPool pool $ do
24+ result <- runQuery query
25+ Just (Only a) <- firstRow result
26+ return a
27+ destroyConnectionPool pool
28+ putChar chr
29+:}
30+a
31+-}
32+
33+{-# LANGUAGE
34+ DeriveFunctor
35+ , FlexibleContexts
36+ , FlexibleInstances
37+ , InstanceSigs
38+ , MultiParamTypeClasses
39+ , RankNTypes
40+ , ScopedTypeVariables
41+ , TypeFamilies
42+ , TypeInType
43+ , UndecidableInstances
44+#-}
45+
46+module Squeal.PostgreSQL.Pool
47+ ( -- * Pools
48+ Pool
49+ , createConnectionPool
50+ , usingConnectionPool
51+ , destroyConnectionPool
52+ ) where
53+
54+import Data.ByteString
55+import Data.Time
56+import Generics.SOP (K(..), unK)
57+import UnliftIO (MonadUnliftIO (..))
58+import UnliftIO.Pool (Pool, createPool, destroyAllResources, withResource)
59+
60+import Squeal.PostgreSQL.PQ
61+
62+-- | Create a striped pool of connections.
63+-- Although the garbage collector will destroy all idle connections when the pool is garbage collected it's recommended to manually `destroyAllResources` when you're done with the pool so that the connections are freed up as soon as possible.
64+createConnectionPool
65+ :: MonadUnliftIO io
66+ => ByteString
67+ -- ^ The passed string can be empty to use all default parameters, or it can
68+ -- contain one or more parameter settings separated by whitespace.
69+ -- Each parameter setting is in the form keyword = value. Spaces around the equal
70+ -- sign are optional. To write an empty value or a value containing spaces,
71+ -- surround it with single quotes, e.g., keyword = 'a value'. Single quotes and
72+ -- backslashes within the value must be escaped with a backslash, i.e., ' and \.
73+ -> Int
74+ -- ^ The number of stripes (distinct sub-pools) to maintain. The smallest acceptable value is 1.
75+ -> NominalDiffTime
76+ -- ^ Amount of time for which an unused connection is kept open. The smallest acceptable value is 0.5 seconds.
77+ -- The elapsed time before destroying a connection may be a little longer than requested, as the reaper thread wakes at 1-second intervals.
78+ -> Int
79+ -- ^ Maximum number of connections to keep open per stripe. The smallest acceptable value is 1.
80+ -- Requests for connections will block if this limit is reached on a single stripe, even if other stripes have idle connections available.
81+ -> io (Pool (K Connection schemas))
82+createConnectionPool conninfo stripes idle maxResrc =
83+ createPool (connectdb conninfo) finish stripes idle maxResrc
84+
85+{-|
86+Temporarily take a connection from a `Pool`, perform an action with it,
87+and return it to the pool afterwards.
88+
89+If the pool has an idle connection available, it is used immediately.
90+Otherwise, if the maximum number of connections has not yet been reached,
91+a new connection is created and used.
92+If the maximum number of connections has been reached, this function blocks
93+until a connection becomes available.
94+-}
95+usingConnectionPool
96+ :: MonadUnliftIO io
97+ => Pool (K Connection schemas) -- ^ pool
98+ -> PQ schemas schemas io x -- ^ session
99+ -> io x
100+usingConnectionPool pool (PQ session) = unK <$> withResource pool session
101+
102+{- |
103+Destroy all connections in all stripes in the pool.
104+Note that this will ignore any exceptions in the destroy function.
105+
106+This function is useful when you detect that all connections
107+in the pool are broken. For example after a database has been
108+restarted all connections opened before the restart will be broken.
109+In that case it's better to close those connections so that
110+`usingConnectionPool` won't take a broken connection from the pool
111+but will open a new connection instead.
112+
113+Another use-case for this function is that when you know you are done
114+with the pool you can destroy all idle connections immediately
115+instead of waiting on the garbage collector to destroy them,
116+thus freeing up those connections sooner.
117+-}
118+destroyConnectionPool
119+ :: MonadUnliftIO io
120+ => Pool (K Connection schemas) -- ^ pool
121+ -> io ()
122+destroyConnectionPool = destroyAllResources
squeal-postgresql/src/Squeal/PostgreSQL/Prettyprint.hsdeleted−67
@@ -1,67 +0,0 @@
1−{-|
2−Module: Squeal.PostgreSQL.PrettyPrint
3−Description: Pretty print helper functions
4−Copyright: (c) Eitan Chatav, 2017
5−Maintainer: eitan@morphism.tech
6−Stability: experimental
7−
8−Pretty print helper functions.
9−-}
10−
11−{-# LANGUAGE
12− MagicHash
13− , OverloadedStrings
14− , PolyKinds
15− , RankNTypes
16− , ScopedTypeVariables
17− , TypeApplications
18−#-}
19−
20−module Squeal.PostgreSQL.Prettyprint where
21−
22−import Data.ByteString (ByteString)
23−import Data.Maybe
24−import Data.Monoid ((<>))
25−import Generics.SOP
26−import GHC.Exts
27−import GHC.TypeLits
28−
29−import qualified Data.ByteString as ByteString
30−
31−-- | Parenthesize a `ByteString`.
32−parenthesized :: ByteString -> ByteString
33−parenthesized str = "(" <> str <> ")"
34−
35−-- | Concatenate two `ByteString`s with a space between.
36−(<+>) :: ByteString -> ByteString -> ByteString
37−str1 <+> str2 = str1 <> " " <> str2
38−
39−-- | Comma separate a list of `ByteString`s.
40−commaSeparated :: [ByteString] -> ByteString
41−commaSeparated = ByteString.intercalate ", "
42−
43−-- | Comma separate the renderings of a heterogeneous list.
44−renderCommaSeparated
45− :: SListI xs
46− => (forall x. expression x -> ByteString)
47− -> NP expression xs -> ByteString
48−renderCommaSeparated render
49− = commaSeparated
50− . hcollapse
51− . hmap (K . render)
52−
53−-- | Comma separate the `Maybe` renderings of a heterogeneous list, dropping
54−-- `Nothing`s.
55−renderCommaSeparatedMaybe
56− :: SListI xs
57− => (forall x. expression x -> Maybe ByteString)
58− -> NP expression xs -> ByteString
59−renderCommaSeparatedMaybe render
60− = commaSeparated
61− . catMaybes
62− . hcollapse
63− . hmap (K . render)
64−
65−-- | Render a promoted `Nat`.
66−renderNat :: KnownNat n => proxy n -> ByteString
67−renderNat (_ :: proxy n) = fromString (show (natVal' (proxy# :: Proxy# n)))
squeal-postgresql/src/Squeal/PostgreSQL/Query.hs+802−505
@@ -1,7 +1,7 @@
11{-|
22Module: Squeal.PostgreSQL.Query
33Description: Squeal queries
4−Copyright: (c) Eitan Chatav, 2017
4+Copyright: (c) Eitan Chatav, 2019
55Maintainer: eitan@morphism.tech
66Stability: experimental
77
@@ -9,69 +9,81 @@ Squeal queries.
99-}
1010
1111{-# LANGUAGE
12− DataKinds
13− , DeriveDataTypeable
12+ ConstraintKinds
1413 , DeriveGeneric
1514 , FlexibleContexts
1615 , FlexibleInstances
1716 , GADTs
1817 , GeneralizedNewtypeDeriving
19− , KindSignatures
2018 , LambdaCase
2119 , MultiParamTypeClasses
20+ , OverloadedLabels
2221 , OverloadedStrings
22+ , QuantifiedConstraints
2323 , ScopedTypeVariables
2424 , StandaloneDeriving
2525 , TypeApplications
26+ , TypeFamilies
2627 , TypeInType
2728 , TypeOperators
29+ , RankNTypes
2830 , UndecidableInstances
29−#-}
31+ #-}
3032
3133module Squeal.PostgreSQL.Query
3234 ( -- * Queries
33− Query (UnsafeQuery, renderQuery)
35+ Query_
36+ , Query (..)
37+ -- ** Select
38+ , select
39+ , select_
40+ , selectDistinct
41+ , selectDistinct_
42+ , selectDistinctOn
43+ , selectDistinctOn_
44+ , Selection (..)
45+ -- ** Values
46+ , values
47+ , values_
48+ -- ** Set Operations
3449 , union
3550 , unionAll
3651 , intersect
3752 , intersectAll
3853 , except
3954 , exceptAll
40− -- * Select
41− , select
42− , selectDistinct
43− , selectStar
44− , selectDistinctStar
45− , selectDotStar
46− , selectDistinctDotStar
55+ -- ** With
56+ , With (..)
57+ , CommonTableExpression (..)
58+ , withRecursive
4759 -- * Table Expressions
4860 , TableExpression (..)
49− , renderTableExpression
5061 , from
5162 , where_
52− , group
63+ , groupBy
5364 , having
54− , orderBy
5565 , limit
5666 , offset
57− -- * From
67+ -- * From Clauses
5868 , FromClause (..)
59− , renderFromClause
69+ , table
70+ , subquery
71+ , view
72+ , common
73+ , crossJoin
74+ , innerJoin
75+ , leftOuterJoin
76+ , rightOuterJoin
77+ , fullOuterJoin
6078 -- * Grouping
61− , By (By, By2)
62− , renderBy
63− , GroupByClause (NoGroups, Group)
64− , renderGroupByClause
65− , HavingClause (NoHaving, Having)
66− , renderHavingClause
67− -- * Sorting
68− , SortExpression (..)
69− , renderSortExpression
79+ , By (..)
80+ , GroupByClause (..)
81+ , HavingClause (..)
7082 ) where
7183
7284import Control.DeepSeq
7385import Data.ByteString (ByteString)
74−import Data.Monoid hiding (All)
86+import Data.Kind (Type)
7587import Data.String
7688import Data.Word
7789import Generics.SOP hiding (from)
@@ -79,335 +91,577 @@ import GHC.TypeLits
7991
8092import qualified GHC.Generics as GHC
8193
94+import Squeal.PostgreSQL.Alias
8295import Squeal.PostgreSQL.Expression
83−import Squeal.PostgreSQL.Prettyprint
96+import Squeal.PostgreSQL.Expression.Logic
97+import Squeal.PostgreSQL.Expression.Sort
98+import Squeal.PostgreSQL.Expression.Window
99+import Squeal.PostgreSQL.List
100+import Squeal.PostgreSQL.PG
101+import Squeal.PostgreSQL.Render
84102import Squeal.PostgreSQL.Schema
85103
104+-- $setup
105+-- >>> import Squeal.PostgreSQL
106+-- >>> import Data.Int (Int32, Int64)
107+-- >>> import Data.Monoid (Sum (..))
108+-- >>> import Data.Text (Text)
109+-- >>> import qualified Generics.SOP as SOP
110+
111+{- |
112+The process of retrieving or the command to retrieve data from
113+a database is called a `Query`.
114+
115+The general `Query` type is parameterized by
116+
117+* @outer :: FromType@ - outer scope for a correlated subquery,
118+* @commons :: FromType@ - scope for all `common` table expressions,
119+* @schemas :: SchemasType@ - scope for all `table`s and `view`s,
120+* @params :: [NullityType]@ - scope for all `Squeal.Expression.Parameter.parameter`s,
121+* @row :: RowType@ - return type of the `Query`.
122+-}
123+newtype Query
124+ (outer :: FromType)
125+ (commons :: FromType)
126+ (schemas :: SchemasType)
127+ (params :: [NullityType])
128+ (row :: RowType)
129+ = UnsafeQuery { renderQuery :: ByteString }
130+ deriving (GHC.Generic,Show,Eq,Ord,NFData)
131+instance RenderSQL (Query outer commons schemas params row) where renderSQL = renderQuery
132+
86133{- |
87−The process of retrieving or the command to retrieve data from a database
88−is called a `Query`. The `select`, `selectStar`, `selectDotStar`,
89−`selectDistinct`, `selectDistinctStar` and `selectDistinctDotStar` commands
90−are used to specify queries.
134+The top level `Query_` type is parameterized by a @schemas@ `SchemasType`,
135+against which the query is type-checked, an input @parameters@ Haskell `Type`,
136+and an ouput row Haskell `Type`.
137+
138+A top-level query can be run
139+using `Squeal.PostgreSQL.PQ.runQueryParams`, or if @parameters = ()@
140+using `Squeal.PostgreSQL.PQ.runQuery`.
141+
142+Generally, @parameters@ will be a Haskell tuple or record whose entries
143+may be referenced using positional
144+`Squeal.PostgreSQL.Expression.Parameter.parameter`s and @row@ will be a
145+Haskell record, whose entries will be targeted using overloaded labels.
146+
147+Let's see some examples of queries.
148+
149+>>> :set -XDeriveAnyClass -XDerivingStrategies
150+>>> :{
151+data Row a b = Row { col1 :: a, col2 :: b }
152+ deriving stock (GHC.Generic)
153+ deriving anyclass (SOP.Generic, SOP.HasDatatypeInfo)
154+:}
91155
92156simple query:
93157
158+>>> type Columns = '["col1" ::: 'NoDef :=> 'NotNull 'PGint4, "col2" ::: 'NoDef :=> 'NotNull 'PGint4]
159+>>> type Schema = '["tab" ::: 'Table ('[] :=> Columns)]
94160>>> :{
95161let
96− query :: Query '["tab" ::: '["col" ::: 'Required ('Null 'PGint4)]] '[]
97− '["col" ::: 'Required ('Null 'PGint4)]
98− query = selectStar (from (Table (#tab `As` #t)))
99−in renderQuery query
162+ query :: Query_ (Public Schema) () (Row Int32 Int32)
163+ query = select Star (from (table #tab))
164+in printSQL query
100165:}
101−"SELECT * FROM tab AS t"
166+SELECT * FROM "tab" AS "tab"
102167
103168restricted query:
104169
105170>>> :{
106171let
107− query :: Query
108− '[ "tab" :::
109− '[ "col1" ::: 'Required ('NotNull 'PGint4)
110− , "col2" ::: 'Required ('NotNull 'PGint4) ]]
111− '[]
112− '[ "sum" ::: 'Required ('NotNull 'PGint4)
113− , "col1" ::: 'Required ('NotNull 'PGint4) ]
114− query =
115− select
116− ((#col1 + #col2) `As` #sum :* #col1 `As` #col1 :* Nil)
117− ( from (Table (#tab `As` #t))
172+ query :: Query_ (Public Schema) () (Row Int32 Int32)
173+ query =
174+ select_ ((#col1 + #col2) `as` #col1 :* #col1 `as` #col2)
175+ ( from (table #tab)
118176 & where_ (#col1 .> #col2)
119177 & where_ (#col2 .> 0) )
120−in renderQuery query
178+in printSQL query
121179:}
122−"SELECT (col1 + col2) AS sum, col1 AS col1 FROM tab AS t WHERE ((col1 > col2) AND (col2 > 0))"
180+SELECT ("col1" + "col2") AS "col1", "col1" AS "col2" FROM "tab" AS "tab" WHERE (("col1" > "col2") AND ("col2" > 0))
123181
124182subquery:
125183
126184>>> :{
127185let
128− query :: Query '["tab" ::: '["col" ::: 'Required ('Null 'PGint4)]] '[]
129− '["col" ::: 'Required ('Null 'PGint4)]
130− query =
131− selectStar
132− (from (Subquery (selectStar (from (Table (#tab `As` #t))) `As` #sub)))
133−in renderQuery query
186+ query :: Query_ (Public Schema) () (Row Int32 Int32)
187+ query = select Star (from (subquery (select Star (from (table #tab)) `as` #sub)))
188+in printSQL query
134189:}
135−"SELECT * FROM (SELECT * FROM tab AS t) AS sub"
190+SELECT * FROM (SELECT * FROM "tab" AS "tab") AS "sub"
136191
137192limits and offsets:
138193
139194>>> :{
140195let
141− query :: Query '["tab" ::: '["col" ::: 'Required ('Null 'PGint4)]] '[]
142− '["col" ::: 'Required ('Null 'PGint4)]
143− query = selectStar
144− (from (Table (#tab `As` #t)) & limit 100 & offset 2 & limit 50 & offset 2)
145−in renderQuery query
196+ query :: Query_ (Public Schema) () (Row Int32 Int32)
197+ query = select Star (from (table #tab) & limit 100 & offset 2 & limit 50 & offset 2)
198+in printSQL query
146199:}
147−"SELECT * FROM tab AS t LIMIT 50 OFFSET 4"
200+SELECT * FROM "tab" AS "tab" LIMIT 50 OFFSET 4
148201
149202parameterized query:
150203
151204>>> :{
152205let
153− query :: Query '["tab" ::: '["col" ::: 'Required ('NotNull 'PGfloat8)]]
154− '[ 'Required ('NotNull 'PGfloat8)]
155− '["col" ::: 'Required ('NotNull 'PGfloat8)]
156− query = selectStar
157− (from (Table (#tab `As` #t)) & where_ (#col .> param @1))
158−in renderQuery query
206+ query :: Query_ (Public Schema) (Only Int32) (Row Int32 Int32)
207+ query = select Star (from (table #tab) & where_ (#col1 .> param @1))
208+in printSQL query
159209:}
160−"SELECT * FROM tab AS t WHERE (col > ($1 :: float8))"
210+SELECT * FROM "tab" AS "tab" WHERE ("col1" > ($1 :: int4))
161211
162212aggregation query:
163213
164214>>> :{
165215let
166− query :: Query
167− '[ "tab" :::
168− '[ "col1" ::: 'Required ('NotNull 'PGint4)
169− , "col2" ::: 'Required ('NotNull 'PGint4) ]]
170− '[]
171− '[ "sum" ::: 'Required ('NotNull 'PGint4)
172− , "col1" ::: 'Required ('NotNull 'PGint4) ]
216+ query :: Query_ (Public Schema) () (Row Int64 Int32)
173217 query =
174− select (sum_ #col2 `As` #sum :* #col1 `As` #col1 :* Nil)
175− ( from (Table (#tab `As` #table1))
176− & group (By #col1 :* Nil)
177− & having (#col1 + sum_ #col2 .> 1) )
178−in renderQuery query
218+ select_ ((fromNull 0 (sum_ (All #col2))) `as` #col1 :* #col1 `as` #col2)
219+ ( from (table (#tab `as` #table1))
220+ & groupBy #col1
221+ & having (sum_ (Distinct #col2) .> 1) )
222+in printSQL query
179223:}
180−"SELECT sum(col2) AS sum, col1 AS col1 FROM tab AS table1 GROUP BY col1 HAVING ((col1 + sum(col2)) > 1)"
224+SELECT COALESCE(sum(ALL "col2"), 0) AS "col1", "col1" AS "col2" FROM "tab" AS "table1" GROUP BY "col1" HAVING (sum(DISTINCT "col2") > 1)
181225
182226sorted query:
183227
184228>>> :{
185229let
186− query :: Query '["tab" ::: '["col" ::: 'Required ('Null 'PGint4)]] '[]
187− '["col" ::: 'Required ('Null 'PGint4)]
188− query = selectStar
189− (from (Table (#tab `As` #t)) & orderBy [#col & AscNullsFirst])
190−in renderQuery query
230+ query :: Query_ (Public Schema) () (Row Int32 Int32)
231+ query = select Star (from (table #tab) & orderBy [#col1 & Asc])
232+in printSQL query
191233:}
192−"SELECT * FROM tab AS t ORDER BY col ASC NULLS FIRST"
234+SELECT * FROM "tab" AS "tab" ORDER BY "col1" ASC
193235
194236joins:
195237
196−>>> :set -XFlexibleContexts
238+>>> :{
239+type OrdersColumns =
240+ '[ "id" ::: 'NoDef :=> 'NotNull 'PGint4
241+ , "price" ::: 'NoDef :=> 'NotNull 'PGfloat4
242+ , "customer_id" ::: 'NoDef :=> 'NotNull 'PGint4
243+ , "shipper_id" ::: 'NoDef :=> 'NotNull 'PGint4 ]
244+:}
245+
246+>>> :{
247+type OrdersConstraints =
248+ '["pk_orders" ::: PrimaryKey '["id"]
249+ ,"fk_customers" ::: ForeignKey '["customer_id"] "customers" '["id"]
250+ ,"fk_shippers" ::: ForeignKey '["shipper_id"] "shippers" '["id"] ]
251+:}
252+
253+>>> type NamesColumns = '["id" ::: 'NoDef :=> 'NotNull 'PGint4, "name" ::: 'NoDef :=> 'NotNull 'PGtext]
254+>>> type CustomersConstraints = '["pk_customers" ::: PrimaryKey '["id"]]
255+>>> type ShippersConstraints = '["pk_shippers" ::: PrimaryKey '["id"]]
256+>>> :{
257+type OrdersSchema =
258+ '[ "orders" ::: 'Table (OrdersConstraints :=> OrdersColumns)
259+ , "customers" ::: 'Table (CustomersConstraints :=> NamesColumns)
260+ , "shippers" ::: 'Table (ShippersConstraints :=> NamesColumns) ]
261+:}
262+
263+>>> :{
264+data Order = Order
265+ { price :: Float
266+ , customerName :: Text
267+ , shipperName :: Text
268+ } deriving GHC.Generic
269+instance SOP.Generic Order
270+instance SOP.HasDatatypeInfo Order
271+:}
272+
197273>>> :{
198274let
199− query :: Query
200− '[ "orders" :::
201− '[ "id" ::: 'Required ('NotNull 'PGint4)
202− , "price" ::: 'Required ('NotNull 'PGfloat4)
203− , "customer_id" ::: 'Required ('NotNull 'PGint4)
204− , "shipper_id" ::: 'Required ('NotNull 'PGint4)
205− ]
206− , "customers" :::
207− '[ "id" ::: 'Required ('NotNull 'PGint4)
208− , "name" ::: 'Required ('NotNull 'PGtext)
209− ]
210− , "shippers" :::
211− '[ "id" ::: 'Required ('NotNull 'PGint4)
212− , "name" ::: 'Required ('NotNull 'PGtext)
213− ]
214− ]
215− '[]
216− '[ "order_price" ::: 'Required ('NotNull 'PGfloat4)
217− , "customer_name" ::: 'Required ('NotNull 'PGtext)
218− , "shipper_name" ::: 'Required ('NotNull 'PGtext)
219− ]
220− query = select
221− ( #o ! #price `As` #order_price :*
222− #c ! #name `As` #customer_name :*
223− #s ! #name `As` #shipper_name :* Nil )
224− ( from (Table (#orders `As` #o)
225− & InnerJoin (Table (#customers `As` #c))
275+ query :: Query_ (Public OrdersSchema) () Order
276+ query = select_
277+ ( #o ! #price `as` #price :*
278+ #c ! #name `as` #customerName :*
279+ #s ! #name `as` #shipperName )
280+ ( from (table (#orders `as` #o)
281+ & innerJoin (table (#customers `as` #c))
226282 (#o ! #customer_id .== #c ! #id)
227− & InnerJoin (Table (#shippers `As` #s))
283+ & innerJoin (table (#shippers `as` #s))
228284 (#o ! #shipper_id .== #s ! #id)) )
229−in renderQuery query
285+in printSQL query
230286:}
231−"SELECT o.price AS order_price, c.name AS customer_name, s.name AS shipper_name FROM orders AS o INNER JOIN customers AS c ON (o.customer_id = c.id) INNER JOIN shippers AS s ON (o.shipper_id = s.id)"
287+SELECT "o"."price" AS "price", "c"."name" AS "customerName", "s"."name" AS "shipperName" FROM "orders" AS "o" INNER JOIN "customers" AS "c" ON ("o"."customer_id" = "c"."id") INNER JOIN "shippers" AS "s" ON ("o"."shipper_id" = "s"."id")
232288
233289self-join:
234290
235291>>> :{
236292let
237− query :: Query '["tab" ::: '["col" ::: 'Required ('Null 'PGint4)]] '[]
238− '["col" ::: 'Required ('Null 'PGint4)]
239− query = selectDotStar #t1
240− (from (Table (#tab `As` #t1) & CrossJoin (Table (#tab `As` #t2))))
241−in renderQuery query
293+ query :: Query_ (Public Schema) () (Row Int32 Int32)
294+ query = select
295+ (#t1 & DotStar)
296+ (from (table (#tab `as` #t1) & crossJoin (table (#tab `as` #t2))))
297+in printSQL query
298+:}
299+SELECT "t1".* FROM "tab" AS "t1" CROSS JOIN "tab" AS "t2"
300+
301+value queries:
302+
303+>>> :{
304+let
305+ query :: Query_ schemas () (Row String Bool)
306+ query = values
307+ ("true" `as` #col1 :* true `as` #col2)
308+ ["false" `as` #col1 :* false `as` #col2]
309+in printSQL query
242310:}
243−"SELECT t1.* FROM tab AS t1 CROSS JOIN tab AS t2"
311+SELECT * FROM (VALUES (E'true', TRUE), (E'false', FALSE)) AS t ("col1", "col2")
244312
245313set operations:
246314
247315>>> :{
248316let
249− query :: Query '["tab" ::: '["col" ::: 'Required ('Null 'PGint4)]] '[]
250− '["col" ::: 'Required ('Null 'PGint4)]
317+ query :: Query_ (Public Schema) () (Row Int32 Int32)
318+ query = select Star (from (table #tab)) `unionAll` select Star (from (table #tab))
319+in printSQL query
320+:}
321+(SELECT * FROM "tab" AS "tab") UNION ALL (SELECT * FROM "tab" AS "tab")
322+
323+with queries:
324+
325+>>> :{
326+let
327+ query :: Query_ (Public Schema) () (Row Int32 Int32)
328+ query = with (
329+ select Star (from (table #tab)) `as` #cte1 :>>
330+ select Star (from (common #cte1)) `as` #cte2
331+ ) (select Star (from (common #cte2)))
332+in printSQL query
333+:}
334+WITH "cte1" AS (SELECT * FROM "tab" AS "tab"), "cte2" AS (SELECT * FROM "cte1" AS "cte1") SELECT * FROM "cte2" AS "cte2"
335+
336+window function queries
337+
338+>>> :{
339+let
340+ query :: Query_ (Public Schema) () (Row Int32 Int64)
341+ query = select
342+ (#col1 & Also (rank `as` #col2 `Over` (partitionBy #col1 & orderBy [#col2 & Asc])))
343+ (from (table #tab))
344+in printSQL query
345+:}
346+SELECT "col1" AS "col1", rank() OVER (PARTITION BY "col1" ORDER BY "col2" ASC) AS "col2" FROM "tab" AS "tab"
347+
348+correlated subqueries
349+
350+>>> :{
351+let
352+ query :: Query_ (Public Schema) () (Only Int32)
251353 query =
252− selectStar (from (Table (#tab `As` #t)))
253− `unionAll`
254− selectStar (from (Table (#tab `As` #t)))
255−in renderQuery query
354+ select (#col1 `as` #fromOnly) (from (table (#tab `as` #t1))
355+ & where_ (exists (
356+ select Star (from (table (#tab `as` #t2))
357+ & where_ (#t2 ! #col2 .== #t1 ! #col1)))))
358+in printSQL query
256359:}
257−"(SELECT * FROM tab AS t) UNION ALL (SELECT * FROM tab AS t)"
258−-}
360+SELECT "col1" AS "fromOnly" FROM "tab" AS "t1" WHERE EXISTS (SELECT * FROM "tab" AS "t2" WHERE ("t2"."col2" = "t1"."col1"))
259361
260−newtype Query
261− (schema :: TablesType)
262− (params :: [NullityType])
263− (columns :: RelationType)
264− = UnsafeQuery { renderQuery :: ByteString }
265− deriving (GHC.Generic,Show,Eq,Ord,NFData)
362+-}
363+type family Query_
364+ (schemas :: SchemasType)
365+ (parameters :: Type)
366+ (row :: Type) where
367+ Query_ schemas params row =
368+ Query '[] '[] schemas (TuplePG params) (RowPG row)
266369
267370-- | The results of two queries can be combined using the set operation
268−-- `union`. Duplicate rows are eliminated.
371+-- `union`. Duplicate rows are eliminated.
269372union
270− :: Query schema params columns
271− -> Query schema params columns
272− -> Query schema params columns
373+ :: Query outer commons schemas params columns
374+ -> Query outer commons schemas params columns
375+ -> Query outer commons schemas params columns
273376q1 `union` q2 = UnsafeQuery $
274− parenthesized (renderQuery q1)
377+ parenthesized (renderSQL q1)
275378 <+> "UNION"
276− <+> parenthesized (renderQuery q2)
379+ <+> parenthesized (renderSQL q2)
277380
278381-- | The results of two queries can be combined using the set operation
279382-- `unionAll`, the disjoint union. Duplicate rows are retained.
280383unionAll
281− :: Query schema params columns
282− -> Query schema params columns
283− -> Query schema params columns
384+ :: Query outer commons schemas params columns
385+ -> Query outer commons schemas params columns
386+ -> Query outer commons schemas params columns
284387q1 `unionAll` q2 = UnsafeQuery $
285− parenthesized (renderQuery q1)
388+ parenthesized (renderSQL q1)
286389 <+> "UNION" <+> "ALL"
287− <+> parenthesized (renderQuery q2)
390+ <+> parenthesized (renderSQL q2)
288391
289392-- | The results of two queries can be combined using the set operation
290393-- `intersect`, the intersection. Duplicate rows are eliminated.
291394intersect
292− :: Query schema params columns
293− -> Query schema params columns
294− -> Query schema params columns
395+ :: Query outer commons schemas params columns
396+ -> Query outer commons schemas params columns
397+ -> Query outer commons schemas params columns
295398q1 `intersect` q2 = UnsafeQuery $
296− parenthesized (renderQuery q1)
399+ parenthesized (renderSQL q1)
297400 <+> "INTERSECT"
298− <+> parenthesized (renderQuery q2)
401+ <+> parenthesized (renderSQL q2)
299402
300403-- | The results of two queries can be combined using the set operation
301404-- `intersectAll`, the intersection. Duplicate rows are retained.
302405intersectAll
303− :: Query schema params columns
304− -> Query schema params columns
305− -> Query schema params columns
406+ :: Query outer commons schemas params columns
407+ -> Query outer commons schemas params columns
408+ -> Query outer commons schemas params columns
306409q1 `intersectAll` q2 = UnsafeQuery $
307− parenthesized (renderQuery q1)
410+ parenthesized (renderSQL q1)
308411 <+> "INTERSECT" <+> "ALL"
309− <+> parenthesized (renderQuery q2)
412+ <+> parenthesized (renderSQL q2)
310413
311414-- | The results of two queries can be combined using the set operation
312415-- `except`, the set difference. Duplicate rows are eliminated.
313416except
314− :: Query schema params columns
315− -> Query schema params columns
316− -> Query schema params columns
417+ :: Query outer commons schemas params columns
418+ -> Query outer commons schemas params columns
419+ -> Query outer commons schemas params columns
317420q1 `except` q2 = UnsafeQuery $
318− parenthesized (renderQuery q1)
421+ parenthesized (renderSQL q1)
319422 <+> "EXCEPT"
320− <+> parenthesized (renderQuery q2)
423+ <+> parenthesized (renderSQL q2)
321424
322425-- | The results of two queries can be combined using the set operation
323426-- `exceptAll`, the set difference. Duplicate rows are retained.
324427exceptAll
325− :: Query schema params columns
326− -> Query schema params columns
327− -> Query schema params columns
428+ :: Query outer commons schemas params columns
429+ -> Query outer commons schemas params columns
430+ -> Query outer commons schemas params columns
328431q1 `exceptAll` q2 = UnsafeQuery $
329− parenthesized (renderQuery q1)
432+ parenthesized (renderSQL q1)
330433 <+> "EXCEPT" <+> "ALL"
331− <+> parenthesized (renderQuery q2)
434+ <+> parenthesized (renderSQL q2)
332435
333436{-----------------------------------------
334437SELECT queries
335438-----------------------------------------}
336439
440+{- | The simplest kinds of `Selection` are `Star` and `DotStar` which
441+emits all columns that a `TableExpression` produces. A select `List`
442+is a list of `Expression`s. A `Selection` could be a list of
443+`WindowFunction`s `Over` `WindowDefinition`. `Additional` `Selection`s can
444+be selected with `Also`.
445+-}
446+data Selection outer commons grp schemas params from row where
447+ Star
448+ :: HasUnique tab from row
449+ => Selection outer commons 'Ungrouped schemas params from row
450+ -- ^ `HasUnique` table in the `FromClause`
451+ DotStar
452+ :: Has tab from row
453+ => Alias tab
454+ -- ^ `Has` table with `Alias`
455+ -> Selection outer commons 'Ungrouped schemas params from row
456+ List
457+ :: SListI row
458+ => NP (Aliased (Expression outer commons grp schemas params from)) row
459+ -- ^ `NP` list of `Aliased` `Expression`s
460+ -> Selection outer commons grp schemas params from row
461+ Over
462+ :: SListI row
463+ => NP (Aliased (WindowFunction outer commons grp schemas params from)) row
464+ -- ^ `NP` list of `Aliased` `WindowFunction`s
465+ -> WindowDefinition outer commons grp schemas params from
466+ -> Selection outer commons grp schemas params from row
467+ Also
468+ :: Selection outer commons grp schemas params from right
469+ -- ^ `Additional` `Selection`
470+ -> Selection outer commons grp schemas params from left
471+ -> Selection outer commons grp schemas params from (Join left right)
472+instance Additional (Selection outer commons grp schemas params from) where
473+ also = Also
474+instance (KnownSymbol col, row ~ '[col ::: ty])
475+ => Aliasable col
476+ (Expression outer commons grp schemas params from ty)
477+ (Selection outer commons grp schemas params from row) where
478+ expr `as` col = List (expr `as` col)
479+instance (Has tab (Join outer from) row0, Has col row0 ty, row1 ~ '[col ::: ty])
480+ => IsQualified tab col
481+ (Selection outer commons 'Ungrouped schemas params from row1) where
482+ tab ! col = tab ! col `as` col
483+instance
484+ ( Has tab (Join outer from) row0
485+ , Has col row0 ty
486+ , row1 ~ '[col ::: ty]
487+ , GroupedBy tab col bys )
488+ => IsQualified tab col
489+ (Selection outer commons ('Grouped bys) schemas params from row1) where
490+ tab ! col = tab ! col `as` col
491+instance (HasUnique tab (Join outer from) row0, Has col row0 ty, row1 ~ '[col ::: ty])
492+ => IsLabel col
493+ (Selection outer commons 'Ungrouped schemas params from row1) where
494+ fromLabel = fromLabel @col `as` Alias
495+instance
496+ ( HasUnique tab (Join outer from) row0
497+ , Has col row0 ty
498+ , row1 ~ '[col ::: ty]
499+ , GroupedBy tab col bys )
500+ => IsLabel col
501+ (Selection outer commons ('Grouped bys) schemas params from row1) where
502+ fromLabel = fromLabel @col `as` Alias
503+
504+instance RenderSQL (Selection outer commons grp schemas params from row) where
505+ renderSQL = \case
506+ List list -> renderCommaSeparated (renderAliased renderSQL) list
507+ Star -> "*"
508+ DotStar tab -> renderSQL tab <> ".*"
509+ Also right left -> renderSQL left <> ", " <> renderSQL right
510+ Over winFns winDef ->
511+ let
512+ renderOver
513+ :: Aliased (WindowFunction outer commons grp schemas params from) field
514+ -> ByteString
515+ renderOver (winFn `As` col) = renderSQL winFn
516+ <+> "OVER" <+> parenthesized (renderSQL winDef)
517+ <+> "AS" <+> renderSQL col
518+ in
519+ renderCommaSeparated renderOver winFns
520+
521+instance IsString
522+ (Selection outer commons grp schemas params from '["fromOnly" ::: 'NotNull 'PGtext]) where
523+ fromString str = fromString str `as` Alias
524+
337525-- | the `TableExpression` in the `select` command constructs an intermediate
338526-- virtual table by possibly combining tables, views, eliminating rows,
339527-- grouping, etc. This table is finally passed on to processing by
340−-- the select list. The select list determines which columns of
528+-- the select list. The `Selection` determines which columns of
341529-- the intermediate table are actually output.
342530select
343− :: SListI columns
344− => NP (Aliased (Expression tables grouping params)) (column ': columns)
345− -- ^ select list
346− -> TableExpression schema params tables grouping
531+ :: (SListI row, row ~ (x ': xs))
532+ => Selection outer commons grp schemas params from row
533+ -- ^ selection
534+ -> TableExpression outer commons grp schemas params from
347535 -- ^ intermediate virtual table
348− -> Query schema params (column ': columns)
349−select list tabs = UnsafeQuery $
536+ -> Query outer commons schemas params row
537+select selection tabexpr = UnsafeQuery $
350538 "SELECT"
351− <+> renderCommaSeparated (renderAliasedAs renderExpression) list
352− <+> renderTableExpression tabs
539+ <+> renderSQL selection
540+ <+> renderSQL tabexpr
541+
542+-- | Like `select` but takes an `NP` list of `Expression`s instead
543+-- of a general `Selection`.
544+select_
545+ :: (SListI row, row ~ (x ': xs))
546+ => NP (Aliased (Expression outer commons grp schemas params from)) row
547+ -- ^ select list
548+ -> TableExpression outer commons grp schemas params from
549+ -- ^ intermediate virtual table
550+ -> Query outer commons schemas params row
551+select_ = select . List
353552
354553-- | After the select list has been processed, the result table can
355554-- be subject to the elimination of duplicate rows using `selectDistinct`.
356555selectDistinct
357− :: SListI columns
358− => NP (Aliased (Expression tables 'Ungrouped params)) (column ': columns)
359− -- ^ select list
360− -> TableExpression schema params tables 'Ungrouped
556+ :: (SListI columns, columns ~ (col ': cols))
557+ => Selection outer commons grp schemas params from columns
558+ -- ^ selection
559+ -> TableExpression outer commons grp schemas params from
361560 -- ^ intermediate virtual table
362− -> Query schema params (column ': columns)
363−selectDistinct list tabs = UnsafeQuery $
561+ -> Query outer commons schemas params columns
562+selectDistinct selection tabexpr = UnsafeQuery $
364563 "SELECT DISTINCT"
365− <+> renderCommaSeparated (renderAliasedAs renderExpression) list
366− <+> renderTableExpression tabs
367−
368−-- | The simplest kind of query is `selectStar` which emits all columns
369−-- that the table expression produces.
370−selectStar
371− :: HasUnique table tables columns
372− => TableExpression schema params tables 'Ungrouped
373− -- ^ intermediate virtual table
374− -> Query schema params columns
375−selectStar tabs = UnsafeQuery $ "SELECT" <+> "*" <+> renderTableExpression tabs
376−
377−-- | A `selectDistinctStar` emits all columns that the table expression
378−-- produces and eliminates duplicate rows.
379−selectDistinctStar
380− :: HasUnique table tables columns
381− => TableExpression schema params tables 'Ungrouped
564+ <+> renderSQL selection
565+ <+> renderSQL tabexpr
566+
567+-- | Like `selectDistinct` but takes an `NP` list of `Expression`s instead
568+-- of a general `Selection`.
569+selectDistinct_
570+ :: (SListI columns, columns ~ (col ': cols))
571+ => NP (Aliased (Expression outer commons grp schemas params from)) columns
572+ -- ^ select list
573+ -> TableExpression outer commons grp schemas params from
382574 -- ^ intermediate virtual table
383− -> Query schema params columns
384−selectDistinctStar tabs = UnsafeQuery $
385− "SELECT DISTINCT" <+> "*" <+> renderTableExpression tabs
386−
387−-- | When working with multiple tables, it can also be useful to ask
388−-- for all the columns of a particular table, using `selectDotStar`.
389−selectDotStar
390− :: Has table tables columns
391− => Alias table
392− -- ^ particular virtual Table
393− -> TableExpression schema params tables 'Ungrouped
575+ -> Query outer commons schemas params columns
576+selectDistinct_ = selectDistinct . List
577+
578+{-|
579+`selectDistinctOn` keeps only the first row of each set of rows where
580+the given expressions evaluate to equal. The DISTINCT ON expressions are
581+interpreted using the same rules as for ORDER BY. ORDER BY is used to
582+ensure that the desired row appears first.
583+
584+The DISTINCT ON expression(s) must match the leftmost ORDER BY expression(s).
585+The ORDER BY clause will normally contain additional expression(s) that
586+determine the desired precedence of rows within each DISTINCT ON group.
587+
588+In order to guarantee they match and reduce redundancy, this function
589+will prepend the The DISTINCT ON expressions to the ORDER BY clause.
590+-}
591+selectDistinctOn
592+ :: (SListI columns, columns ~ (col ': cols))
593+ => [SortExpression outer commons grp schemas params from]
594+ -- ^ DISTINCT ON expression(s) and prepended to ORDER BY clause
595+ -> Selection outer commons grp schemas params from columns
596+ -- ^ selection
597+ -> TableExpression outer commons grp schemas params from
394598 -- ^ intermediate virtual table
395− -> Query schema params columns
396−selectDotStar table tables = UnsafeQuery $
397− "SELECT" <+> renderAlias table <> ".*" <+> renderTableExpression tables
398−
399−-- | A `selectDistinctDotStar` asks for all the columns of a particular table,
400−-- and eliminates duplicate rows.
401−selectDistinctDotStar
402− :: Has table tables columns
403− => Alias table
404− -- ^ particular virtual Table
405− -> TableExpression schema params tables 'Ungrouped
599+ -> Query outer commons schemas params columns
600+selectDistinctOn distincts selection tab = UnsafeQuery $
601+ "SELECT DISTINCT ON"
602+ <+> parenthesized (commaSeparated (renderDistinctOn <$> distincts))
603+ <+> renderSQL selection
604+ <+> renderSQL (tab {orderByClause = distincts <> orderByClause tab})
605+ where
606+ renderDistinctOn = \case
607+ Asc expression -> renderSQL expression
608+ Desc expression -> renderSQL expression
609+ AscNullsFirst expression -> renderSQL expression
610+ DescNullsFirst expression -> renderSQL expression
611+ AscNullsLast expression -> renderSQL expression
612+ DescNullsLast expression -> renderSQL expression
613+
614+-- | Like `selectDistinctOn` but takes an `NP` list of `Expression`s instead
615+-- of a general `Selection`.
616+selectDistinctOn_
617+ :: (SListI columns, columns ~ (col ': cols))
618+ => [SortExpression outer commons grp schemas params from]
619+ -- ^ distinct on and return the first row in ordering
620+ -> NP (Aliased (Expression outer commons grp schemas params from)) columns
621+ -- ^ selection
622+ -> TableExpression outer commons grp schemas params from
406623 -- ^ intermediate virtual table
407− -> Query schema params columns
408−selectDistinctDotStar table tables = UnsafeQuery $
409− "SELECT DISTINCT" <+> renderAlias table <> ".*"
410− <+> renderTableExpression tables
624+ -> Query outer commons schemas params columns
625+selectDistinctOn_ distincts = selectDistinctOn distincts . List
626+
627+-- | `values` computes a row value or set of row values
628+-- specified by value expressions. It is most commonly used
629+-- to generate a “constant table” within a larger command,
630+-- but it can be used on its own.
631+--
632+-- >>> type Row = '["a" ::: 'NotNull 'PGint4, "b" ::: 'NotNull 'PGtext]
633+-- >>> let query = values (1 `as` #a :* "one" `as` #b) [] :: Query outer commons schemas '[] Row
634+-- >>> printSQL query
635+-- SELECT * FROM (VALUES (1, E'one')) AS t ("a", "b")
636+values
637+ :: SListI cols
638+ => NP (Aliased (Expression outer commons 'Ungrouped schemas params '[] )) cols
639+ -> [NP (Aliased (Expression outer commons 'Ungrouped schemas params '[] )) cols]
640+ -- ^ When more than one row is specified, all the rows must
641+ -- must have the same number of elements
642+ -> Query outer commons schemas params cols
643+values rw rws = UnsafeQuery $ "SELECT * FROM"
644+ <+> parenthesized (
645+ "VALUES"
646+ <+> commaSeparated
647+ ( parenthesized
648+ . renderCommaSeparated renderValuePart <$> rw:rws )
649+ ) <+> "AS t"
650+ <+> parenthesized (renderCommaSeparated renderAliasPart rw)
651+ where
652+ renderAliasPart, renderValuePart
653+ :: Aliased (Expression outer commons 'Ungrouped schemas params '[] ) ty -> ByteString
654+ renderAliasPart (_ `As` name) = renderSQL name
655+ renderValuePart (value `As` _) = renderSQL value
656+
657+-- | `values_` computes a row value or set of row values
658+-- specified by value expressions.
659+values_
660+ :: SListI cols
661+ => NP (Aliased (Expression outer commons 'Ungrouped schemas params '[] )) cols
662+ -- ^ one row of values
663+ -> Query outer commons schemas params cols
664+values_ rw = values rw []
411665
412666{-----------------------------------------
413667Table Expressions
@@ -420,15 +674,17 @@ Table Expressions
420674-- to a table on disk, a so-called base table, but more complex expressions
421675-- can be used to modify or combine base tables in various ways.
422676data TableExpression
423− (schema :: TablesType)
677+ (outer :: FromType)
678+ (commons :: FromType)
679+ (grp :: Grouping)
680+ (schemas :: SchemasType)
424681 (params :: [NullityType])
425− (tables :: RelationsType)
426− (grouping :: Grouping)
682+ (from :: FromType)
427683 = TableExpression
428− { fromClause :: FromClause schema params tables
684+ { fromClause :: FromClause outer commons schemas params from
429685 -- ^ A table reference that can be a table name, or a derived table such
430686 -- as a subquery, a @JOIN@ construct, or complex combinations of these.
431− , whereClause :: [Condition tables 'Ungrouped params]
687+ , whereClause :: [Condition outer commons 'Ungrouped schemas params from]
432688 -- ^ optional search coditions, combined with `.&&`. After the processing
433689 -- of the `fromClause` is done, each row of the derived virtual table
434690 -- is checked against the search condition. If the result of the
@@ -437,20 +693,20 @@ data TableExpression
437693 -- at least one column of the table generated in the `fromClause`;
438694 -- this is not required, but otherwise the WHERE clause will
439695 -- be fairly useless.
440− , groupByClause :: GroupByClause tables grouping
696+ , groupByClause :: GroupByClause grp from
441697 -- ^ The `groupByClause` is used to group together those rows in a table
442698 -- that have the same values in all the columns listed. The order in which
443699 -- the columns are listed does not matter. The effect is to combine each
444700 -- set of rows having common values into one group row that represents all
445701 -- rows in the group. This is done to eliminate redundancy in the output
446702 -- and/or compute aggregates that apply to these groups.
447− , havingClause :: HavingClause tables grouping params
703+ , havingClause :: HavingClause outer commons grp schemas params from
448704 -- ^ If a table has been grouped using `groupBy`, but only certain groups
449705 -- are of interest, the `havingClause` can be used, much like a
450706 -- `whereClause`, to eliminate groups from the result. Expressions in the
451707 -- `havingClause` can refer both to grouped expressions and to ungrouped
452708 -- expressions (which necessarily involve an aggregate function).
453− , orderByClause :: [SortExpression tables grouping params]
709+ , orderByClause :: [SortExpression outer commons grp schemas params from]
454710 -- ^ The `orderByClause` is for optional sorting. When more than one
455711 -- `SortExpression` is specified, the later (right) values are used to sort
456712 -- rows that are equal according to the earlier (left) values.
@@ -460,110 +716,102 @@ data TableExpression
460716 -- will be returned (but possibly fewer, if the query itself yields
461717 -- fewer rows).
462718 , offsetClause :: [Word64]
463− -- ^ The `offsetClause` is combined with `+` to give an offset count
719+ -- ^ The `offsetClause` is combined with `Prelude.+` to give an offset count
464720 -- if nonempty. The offset count says to skip that many rows before
465721 -- beginning to return rows. The rows are skipped before the limit count
466722 -- is applied.
467− }
723+ } deriving (GHC.Generic)
468724
469725-- | Render a `TableExpression`
470−renderTableExpression
471− :: TableExpression schema params tables grouping
472− -> ByteString
473−renderTableExpression
474− (TableExpression tables whs' grps' hvs' srts' lims' offs') = mconcat
475− [ "FROM ", renderFromClause tables
476− , renderWheres whs'
477− , renderGroupByClause grps'
478− , renderHavingClause hvs'
479− , renderOrderByClause srts'
480− , renderLimits lims'
481− , renderOffsets offs'
482− ]
483− where
484− renderWheres = \case
485− [] -> ""
486− wh:[] -> " WHERE" <+> renderExpression wh
487− wh:whs -> " WHERE" <+> renderExpression (foldr (.&&) wh whs)
488− renderOrderByClause = \case
489− [] -> ""
490− srts -> " ORDER BY"
491− <+> commaSeparated (renderSortExpression <$> srts)
492− renderLimits = \case
493− [] -> ""
494− lims -> " LIMIT" <+> fromString (show (minimum lims))
495− renderOffsets = \case
496− [] -> ""
497− offs -> " OFFSET" <+> fromString (show (sum offs))
726+instance RenderSQL (TableExpression outer commons grp schemas params from) where
727+ renderSQL
728+ (TableExpression frm' whs' grps' hvs' srts' lims' offs') = mconcat
729+ [ "FROM ", renderSQL frm'
730+ , renderWheres whs'
731+ , renderSQL grps'
732+ , renderSQL hvs'
733+ , renderOrderByClause srts'
734+ , renderLimits lims'
735+ , renderOffsets offs' ]
736+ where
737+ renderWheres = \case
738+ [] -> ""
739+ wh:[] -> " WHERE" <+> renderSQL wh
740+ wh:whs -> " WHERE" <+> renderSQL (foldr (.&&) wh whs)
741+ renderOrderByClause = \case
742+ [] -> ""
743+ srts -> " ORDER BY"
744+ <+> commaSeparated (renderSQL <$> srts)
745+ renderLimits = \case
746+ [] -> ""
747+ lims -> " LIMIT" <+> fromString (show (minimum lims))
748+ renderOffsets = \case
749+ [] -> ""
750+ offs -> " OFFSET" <+> fromString (show (sum offs))
498751
499752-- | A `from` generates a `TableExpression` from a table reference that can be
500753-- a table name, or a derived table such as a subquery, a JOIN construct,
501754-- or complex combinations of these. A `from` may be transformed by `where_`,
502−-- `group`, `having`, `orderBy`, `limit` and `offset`, using the `&` operator
755+-- `groupBy`, `having`, `orderBy`, `limit` and `offset`, using the `&` operator
503756-- to match the left-to-right sequencing of their placement in SQL.
504757from
505− :: FromClause schema params tables -- ^ table reference
506− -> TableExpression schema params tables 'Ungrouped
507−from tables = TableExpression tables [] NoGroups NoHaving [] [] []
758+ :: FromClause outer commons schemas params from -- ^ table reference
759+ -> TableExpression outer commons 'Ungrouped schemas params from
760+from tab = TableExpression tab [] noGroups NoHaving [] [] []
508761
509762-- | A `where_` is an endomorphism of `TableExpression`s which adds a
510763-- search condition to the `whereClause`.
511764where_
512− :: Condition tables 'Ungrouped params
513− -> TableExpression schema params tables grouping
514− -> TableExpression schema params tables grouping
515−where_ wh tables = tables {whereClause = wh : whereClause tables}
765+ :: Condition outer commons 'Ungrouped schemas params from -- ^ filtering condition
766+ -> TableExpression outer commons grp schemas params from
767+ -> TableExpression outer commons grp schemas params from
768+where_ wh rels = rels {whereClause = wh : whereClause rels}
516769
517−-- | A `group` is a transformation of `TableExpression`s which switches
518−-- its `Grouping` from `Ungrouped` to `Grouped`. Use @group Nil@ to perform
770+-- | A `groupBy` is a transformation of `TableExpression`s which switches
771+-- its `Grouping` from `Ungrouped` to `Grouped`. Use @groupBy Nil@ to perform
519772-- a "grand total" aggregation query.
520−group
773+groupBy
521774 :: SListI bys
522− => NP (By tables) bys
523− -> TableExpression schema params tables 'Ungrouped
524− -> TableExpression schema params tables ('Grouped bys)
525−group bys tables = TableExpression
526− { fromClause = fromClause tables
527− , whereClause = whereClause tables
528− , groupByClause = Group bys
775+ => NP (By from) bys -- ^ grouped columns
776+ -> TableExpression outer commons 'Ungrouped schemas params from
777+ -> TableExpression outer commons ('Grouped bys) schemas params from
778+groupBy bys rels = TableExpression
779+ { fromClause = fromClause rels
780+ , whereClause = whereClause rels
781+ , groupByClause = group bys
529782 , havingClause = Having []
530783 , orderByClause = []
531− , limitClause = limitClause tables
532− , offsetClause = offsetClause tables
784+ , limitClause = limitClause rels
785+ , offsetClause = offsetClause rels
533786 }
534787
535788-- | A `having` is an endomorphism of `TableExpression`s which adds a
536789-- search condition to the `havingClause`.
537790having
538− :: Condition tables ('Grouped bys) params
539− -> TableExpression schema params tables ('Grouped bys)
540− -> TableExpression schema params tables ('Grouped bys)
541−having hv tables = tables
542− { havingClause = case havingClause tables of Having hvs -> Having (hv:hvs) }
543−
544−-- | An `orderBy` is an endomorphism of `TableExpression`s which appends an
545−-- ordering to the right of the `orderByClause`.
546−orderBy
547− :: [SortExpression tables grouping params]
548− -> TableExpression schema params tables grouping
549− -> TableExpression schema params tables grouping
550−orderBy srts tables = tables {orderByClause = orderByClause tables ++ srts}
791+ :: Condition outer commons ('Grouped bys) schemas params from -- ^ having condition
792+ -> TableExpression outer commons ('Grouped bys) schemas params from
793+ -> TableExpression outer commons ('Grouped bys) schemas params from
794+having hv rels = rels
795+ { havingClause = case havingClause rels of Having hvs -> Having (hv:hvs) }
796+
797+instance OrderBy TableExpression where
798+ orderBy srts rels = rels {orderByClause = orderByClause rels ++ srts}
551799
552800-- | A `limit` is an endomorphism of `TableExpression`s which adds to the
553801-- `limitClause`.
554802limit
555− :: Word64
556− -> TableExpression schema params tables grouping
557− -> TableExpression schema params tables grouping
558−limit lim tables = tables {limitClause = lim : limitClause tables}
803+ :: Word64 -- ^ limit parameter
804+ -> TableExpression outer commons grp schemas params from
805+ -> TableExpression outer commons grp schemas params from
806+limit lim rels = rels {limitClause = lim : limitClause rels}
559807
560808-- | An `offset` is an endomorphism of `TableExpression`s which adds to the
561809-- `offsetClause`.
562810offset
563− :: Word64
564− -> TableExpression schema params tables grouping
565− -> TableExpression schema params tables grouping
566−offset off tables = tables {offsetClause = off : offsetClause tables}
811+ :: Word64 -- ^ offset parameter
812+ -> TableExpression outer commons grp schemas params from
813+ -> TableExpression outer commons grp schemas params from
814+offset off rels = rels {offsetClause = off : offsetClause rels}
567815
568816{-----------------------------------------
569817FROM clauses
@@ -572,230 +820,279 @@ FROM clauses
572820{- |
573821A `FromClause` can be a table name, or a derived table such
574822as a subquery, a @JOIN@ construct, or complex combinations of these.
823+-}
824+newtype FromClause outer commons schemas params from
825+ = UnsafeFromClause { renderFromClause :: ByteString }
826+ deriving (GHC.Generic,Show,Eq,Ord,NFData)
827+instance RenderSQL (FromClause outer commons schemas params from) where
828+ renderSQL = renderFromClause
829+
830+-- | A real `table` is a table from the database.
831+table
832+ :: (Has sch schemas schema, Has tab schema ('Table table))
833+ => Aliased (QualifiedAlias sch) (alias ::: tab)
834+ -> FromClause outer commons schemas params '[alias ::: TableToRow table]
835+table (tab `As` alias) = UnsafeFromClause $
836+ renderSQL tab <+> "AS" <+> renderSQL alias
837+
838+-- | `subquery` derives a table from a `Query`.
839+subquery
840+ :: Aliased (Query outer commons schemas params) query
841+ -> FromClause outer commons schemas params '[query]
842+subquery = UnsafeFromClause . renderAliased (parenthesized . renderSQL)
843+
844+-- | `view` derives a table from a `View`.
845+view
846+ :: (Has sch schemas schema, Has vw schema ('View view))
847+ => Aliased (QualifiedAlias sch) (alias ::: vw)
848+ -> FromClause outer commons schemas params '[alias ::: view]
849+view (vw `As` alias) = UnsafeFromClause $
850+ renderSQL vw <+> "AS" <+> renderSQL alias
851+
852+-- | `common` derives a table from a common table expression.
853+common
854+ :: Has cte commons common
855+ => Aliased Alias (alias ::: cte)
856+ -> FromClause outer commons schemas params '[alias ::: common]
857+common (cte `As` alias) = UnsafeFromClause $
858+ renderSQL cte <+> "AS" <+> renderSQL alias
859+
860+instance Additional (FromClause outer commons schemas params) where
861+ also right left = UnsafeFromClause $
862+ renderSQL left <> ", " <> renderSQL right
575863
576−* A real `Table` is a table from the schema.
577−
578−* `Subquery` derives a table from a `Query`.
579−
580−* A joined table is a table derived from two other (real or derived) tables
581−according to the rules of the particular join type. `CrossJoin`, `InnerJoin`,
582−`LeftOuterJoin`, `RightOuterJoin` and `FullOuterJoin` are available and can
583−be nested using the `&` operator to match the left-to-right sequencing of
584−their placement in SQL.
585−
586− * @t1 & CrossJoin t2@. For every possible combination of rows from
587− @t1@ and @t2@ (i.e., a Cartesian product), the joined table will contain
588− a row consisting of all columns in @t1@ followed by all columns in @t2@.
589− If the tables have @n@ and @m@ rows respectively, the joined table will
590− have @n * m@ rows.
591−
592− * @t1 & InnerJoin t2 on@. For each row @r1@ of @t1@, the joined
593− table has a row for each row in @t2@ that satisfies the @on@ condition
594− with @r1@
595−
596− * @t1 & LeftOuterJoin t2 on@. First, an inner join is performed.
597− Then, for each row in @t1@ that does not satisfy the @on@ condition with
598− any row in @t2@, a joined row is added with null values in columns of @t2@.
599− Thus, the joined table always has at least one row for each row in @t1@.
600−
601− * @t1 & RightOuterJoin t2 on@. First, an inner join is performed.
602− Then, for each row in @t2@ that does not satisfy the @on@ condition with
603− any row in @t1@, a joined row is added with null values in columns of @t1@.
864+{- |
865+@left & crossJoin right@. For every possible combination of rows from
866+@left@ and @right@ (i.e., a Cartesian product), the joined table will contain
867+a row consisting of all columns in @left@ followed by all columns in @right@.
868+If the tables have @n@ and @m@ rows respectively, the joined table will
869+have @n * m@ rows.
870+-}
871+crossJoin
872+ :: FromClause outer commons schemas params right
873+ -- ^ right
874+ -> FromClause outer commons schemas params left
875+ -- ^ left
876+ -> FromClause outer commons schemas params (Join left right)
877+crossJoin right left = UnsafeFromClause $
878+ renderSQL left <+> "CROSS JOIN" <+> renderSQL right
879+
880+{- | @left & innerJoin right on@. The joined table is filtered by
881+the @on@ condition.
882+-}
883+innerJoin
884+ :: FromClause outer commons schemas params right
885+ -- ^ right
886+ -> Condition outer commons 'Ungrouped schemas params (Join left right)
887+ -- ^ @on@ condition
888+ -> FromClause outer commons schemas params left
889+ -- ^ left
890+ -> FromClause outer commons schemas params (Join left right)
891+innerJoin right on left = UnsafeFromClause $
892+ renderSQL left <+> "INNER JOIN" <+> renderSQL right
893+ <+> "ON" <+> renderSQL on
894+
895+{- | @left & leftOuterJoin right on@. First, an inner join is performed.
896+ Then, for each row in @left@ that does not satisfy the @on@ condition with
897+ any row in @right@, a joined row is added with null values in columns of @right@.
898+ Thus, the joined table always has at least one row for each row in @left@.
899+-}
900+leftOuterJoin
901+ :: FromClause outer commons schemas params right
902+ -- ^ right
903+ -> Condition outer commons 'Ungrouped schemas params (Join left right)
904+ -- ^ @on@ condition
905+ -> FromClause outer commons schemas params left
906+ -- ^ left
907+ -> FromClause outer commons schemas params (Join left (NullifyFrom right))
908+leftOuterJoin right on left = UnsafeFromClause $
909+ renderSQL left <+> "LEFT OUTER JOIN" <+> renderSQL right
910+ <+> "ON" <+> renderSQL on
911+
912+{- | @left & rightOuterJoin right on@. First, an inner join is performed.
913+ Then, for each row in @right@ that does not satisfy the @on@ condition with
914+ any row in @left@, a joined row is added with null values in columns of @left@.
604915 This is the converse of a left join: the result table will always
605− have a row for each row in @t2@.
606−
607− * @t1 & FullOuterJoin t2 on@. First, an inner join is performed.
608− Then, for each row in @t1@ that does not satisfy the @on@ condition with
609− any row in @t2@, a joined row is added with null values in columns of @t2@.
610− Also, for each row of @t2@ that does not satisfy the join condition
611− with any row in @t1@, a joined row with null values in the columns of @t1@
916+ have a row for each row in @right@.
917+-}
918+rightOuterJoin
919+ :: FromClause outer commons schemas params right
920+ -- ^ right
921+ -> Condition outer commons 'Ungrouped schemas params (Join left right)
922+ -- ^ @on@ condition
923+ -> FromClause outer commons schemas params left
924+ -- ^ left
925+ -> FromClause outer commons schemas params (Join (NullifyFrom left) right)
926+rightOuterJoin right on left = UnsafeFromClause $
927+ renderSQL left <+> "RIGHT OUTER JOIN" <+> renderSQL right
928+ <+> "ON" <+> renderSQL on
929+
930+{- | @left & fullOuterJoin right on@. First, an inner join is performed.
931+ Then, for each row in @left@ that does not satisfy the @on@ condition with
932+ any row in @right@, a joined row is added with null values in columns of @right@.
933+ Also, for each row of @right@ that does not satisfy the join condition
934+ with any row in @left@, a joined row with null values in the columns of @left@
612935 is added.
613936-}
614−data FromClause schema params tables where
615− Table
616− :: Aliased (Table schema) table
617− -> FromClause schema params '[table]
618− Subquery
619− :: Aliased (Query schema params) table
620− -> FromClause schema params '[table]
621− CrossJoin
622− :: FromClause schema params right
623− -> FromClause schema params left
624− -> FromClause schema params (Join left right)
625− InnerJoin
626− :: FromClause schema params right
627− -> Condition (Join left right) 'Ungrouped params
628− -> FromClause schema params left
629− -> FromClause schema params (Join left right)
630− LeftOuterJoin
631− :: FromClause schema params right
632− -> Condition (Join left right) 'Ungrouped params
633− -> FromClause schema params left
634− -> FromClause schema params (Join left (NullifyTables right))
635− RightOuterJoin
636− :: FromClause schema params right
637− -> Condition (Join left right) 'Ungrouped params
638− -> FromClause schema params left
639− -> FromClause schema params (Join (NullifyTables left) right)
640− FullOuterJoin
641− :: FromClause schema params right
642− -> Condition (Join left right) 'Ungrouped params
643− -> FromClause schema params left
644− -> FromClause schema params
645− (Join (NullifyTables left) (NullifyTables right))
646−
647−-- | Renders a `FromClause`.
648−renderFromClause :: FromClause schema params tables -> ByteString
649−renderFromClause = \case
650− Table table -> renderAliasedAs renderTable table
651− Subquery selection -> renderAliasedAs (parenthesized . renderQuery) selection
652− CrossJoin right left ->
653− renderFromClause left <+> "CROSS JOIN" <+> renderFromClause right
654− InnerJoin right on left -> renderJoin "INNER JOIN" right on left
655− LeftOuterJoin right on left -> renderJoin "LEFT OUTER JOIN" right on left
656− RightOuterJoin right on left -> renderJoin "RIGHT OUTER JOIN" right on left
657− FullOuterJoin right on left -> renderJoin "FULL OUTER JOIN" right on left
658− where
659− renderJoin op right on left =
660− renderFromClause left <+> op <+> renderFromClause right
661− <+> "ON" <+> renderExpression on
662−
663−-- joinRef
664−-- :: ( Has lefttable schema (constraints :=> leftcolumns)
665−-- , leftrel ~ ColumnsToRelation leftcolumns
666−-- , Has righttable schema right
667−-- , rightrel ~ ColumnsToRelation (TableToColumns right)
668−-- , Has ref constraints ('ForeignKey keys reftable refs)
669−-- , SListI keys, All KnownSymbol keys
670−-- , SListI refs, All KnownSymbol refs
671−-- , KnownSymbol leftalias, KnownSymbol rightalias
672−-- )
673−-- => Aliased Alias (rightalias ::: righttable)
674−-- -> Alias ref
675−-- -> Aliased Alias (leftalias ::: lefttable)
676−-- -> FromClause schema params '[leftalias ::: leftrel, rightalias ::: rightrel]
677−-- joinRef
678−-- ((_ :: Alias righttable) `As` rightalias)
679−-- ref
680−-- ((_ :: Alias lefttable) `As` leftalias) =
681−-- InnerJoin
682−-- (Table (fromLabel @righttable `As` rightalias))
683−-- refEq
684−-- (Table (fromLabel @lefttable `As` leftalias))
685−-- where
686−-- refEq = undefined
937+fullOuterJoin
938+ :: FromClause outer commons schemas params right
939+ -- ^ right
940+ -> Condition outer commons 'Ungrouped schemas params (Join left right)
941+ -- ^ @on@ condition
942+ -> FromClause outer commons schemas params left
943+ -- ^ left
944+ -> FromClause outer commons schemas params
945+ (Join (NullifyFrom left) (NullifyFrom right))
946+fullOuterJoin right on left = UnsafeFromClause $
947+ renderSQL left <+> "FULL OUTER JOIN" <+> renderSQL right
948+ <+> "ON" <+> renderSQL on
687949
688950{-----------------------------------------
689951Grouping
690952-----------------------------------------}
691953
692−-- | `By`s are used in `group` to reference a list of columns which are then
954+-- | `By`s are used in `groupBy` to reference a list of columns which are then
693955-- used to group together those rows in a table that have the same values
694956-- in all the columns listed. @By \#col@ will reference an unambiguous
695957-- column @col@; otherwise @By2 (\#tab \! \#col)@ will reference a table
696958-- qualified column @tab.col@.
697959data By
698− (tables :: RelationsType)
960+ (from :: FromType)
699961 (by :: (Symbol,Symbol)) where
700− By
701− :: (HasUnique table tables columns, Has column columns ty)
962+ By1
963+ :: (HasUnique table from columns, Has column columns ty)
702964 => Alias column
703− -> By tables '(table, column)
965+ -> By from '(table, column)
704966 By2
705− :: (Has table tables columns, Has column columns ty)
706− => (Alias table, Alias column)
707− -> By tables '(table, column)
708−deriving instance Show (By tables by)
709−deriving instance Eq (By tables by)
710−deriving instance Ord (By tables by)
711−
712−-- | Renders a `By`.
713−renderBy :: By tables tabcolty -> ByteString
714−renderBy = \case
715− By column -> renderAlias column
716− By2 (table, column) -> renderAlias table <> "." <> renderAlias column
967+ :: (Has table from columns, Has column columns ty)
968+ => Alias table
969+ -> Alias column
970+ -> By from '(table, column)
971+deriving instance Show (By from by)
972+deriving instance Eq (By from by)
973+deriving instance Ord (By from by)
974+instance RenderSQL (By from by) where
975+ renderSQL = \case
976+ By1 column -> renderSQL column
977+ By2 rel column -> renderSQL rel <> "." <> renderSQL column
978+
979+instance (HasUnique rel rels cols, Has col cols ty, by ~ '(rel, col))
980+ => IsLabel col (By rels by) where fromLabel = By1 fromLabel
981+instance (HasUnique rel rels cols, Has col cols ty, bys ~ '[ '(rel, col)])
982+ => IsLabel col (NP (By rels) bys) where fromLabel = By1 fromLabel :* Nil
983+instance (Has rel rels cols, Has col cols ty, by ~ '(rel, col))
984+ => IsQualified rel col (By rels by) where (!) = By2
985+instance (Has rel rels cols, Has col cols ty, bys ~ '[ '(rel, col)])
986+ => IsQualified rel col (NP (By rels) bys) where
987+ rel ! col = By2 rel col :* Nil
717988
718989-- | A `GroupByClause` indicates the `Grouping` of a `TableExpression`.
719990-- A `NoGroups` indicates `Ungrouped` while a `Group` indicates `Grouped`.
720991-- @NoGroups@ is distinguised from @Group Nil@ since no aggregation can be
721992-- done on @NoGroups@ while all output `Expression`s must be aggregated
722−-- in @Group Nil@.
723−data GroupByClause tables grouping where
724− NoGroups :: GroupByClause tables 'Ungrouped
725− Group
726− :: SListI bys
727− => NP (By tables) bys
728− -> GroupByClause tables ('Grouped bys)
729−
730−-- | Renders a `GroupByClause`.
731−renderGroupByClause :: GroupByClause tables grouping -> ByteString
732−renderGroupByClause = \case
733− NoGroups -> ""
734− Group Nil -> ""
735− Group bys -> " GROUP BY" <+> renderCommaSeparated renderBy bys
993+-- in @Group Nil@. In general, all output `Expression`s in the
994+-- complement of @bys@ must be aggregated in @Group bys@.
995+newtype GroupByClause grp from = UnsafeGroupByClause
996+ { renderGroupByClause :: ByteString }
997+ deriving (GHC.Generic,Show,Eq,Ord,NFData)
998+instance RenderSQL (GroupByClause grp from) where
999+ renderSQL = renderGroupByClause
1000+noGroups :: GroupByClause 'Ungrouped from
1001+noGroups = UnsafeGroupByClause ""
1002+group
1003+ :: SListI bys
1004+ => NP (By from) bys
1005+ -> GroupByClause ('Grouped bys) from
1006+group bys = UnsafeGroupByClause $ case bys of
1007+ Nil -> ""
1008+ bys' -> " GROUP BY" <+> renderCommaSeparated renderSQL bys'
7361009
7371010-- | A `HavingClause` is used to eliminate groups that are not of interest.
7381011-- An `Ungrouped` `TableExpression` may only use `NoHaving` while a `Grouped`
7391012-- `TableExpression` must use `Having` whose conditions are combined with
7401013-- `.&&`.
741−data HavingClause tables grouping params where
742− NoHaving :: HavingClause tables 'Ungrouped params
1014+data HavingClause outer commons grp schemas params from where
1015+ NoHaving :: HavingClause outer commons 'Ungrouped schemas params from
7431016 Having
744− :: [Condition tables ('Grouped bys) params]
745− -> HavingClause tables ('Grouped bys) params
746−deriving instance Show (HavingClause tables grouping params)
747−deriving instance Eq (HavingClause tables grouping params)
748−deriving instance Ord (HavingClause tables grouping params)
1017+ :: [Condition outer commons ('Grouped bys) schemas params from]
1018+ -> HavingClause outer commons ('Grouped bys) schemas params from
1019+deriving instance Show (HavingClause outer commons grp schemas params from)
1020+deriving instance Eq (HavingClause outer commons grp schemas params from)
1021+deriving instance Ord (HavingClause outer commons grp schemas params from)
7491022
7501023-- | Render a `HavingClause`.
751−renderHavingClause :: HavingClause tables grouping params -> ByteString
752−renderHavingClause = \case
753− NoHaving -> ""
754− Having [] -> ""
755− Having conditions ->
756− " HAVING" <+> commaSeparated (renderExpression <$> conditions)
757−
758−{-----------------------------------------
759−Sorting
760−-----------------------------------------}
1024+instance RenderSQL (HavingClause outer commons grp schemas params from) where
1025+ renderSQL = \case
1026+ NoHaving -> ""
1027+ Having [] -> ""
1028+ Having conditions ->
1029+ " HAVING" <+> commaSeparated (renderSQL <$> conditions)
1030+
1031+-- | A `CommonTableExpression` is an auxiliary statement in a `with` clause.
1032+data CommonTableExpression statement
1033+ (schemas :: SchemasType)
1034+ (params :: [NullityType])
1035+ (commons0 :: FromType)
1036+ (commons1 :: FromType) where
1037+ CommonTableExpression
1038+ :: Aliased (statement commons schemas params) (cte ::: common)
1039+ -> CommonTableExpression statement schemas params commons (cte ::: common ': commons)
1040+instance
1041+ ( KnownSymbol cte
1042+ , commons1 ~ (cte ::: common ': commons)
1043+ ) => Aliasable cte
1044+ (statement commons schemas params common)
1045+ (CommonTableExpression statement schemas params commons commons1) where
1046+ statement `as` cte = CommonTableExpression (statement `as` cte)
1047+instance
1048+ ( KnownSymbol cte
1049+ , commons1 ~ (cte ::: common ': commons)
1050+ ) => Aliasable cte
1051+ (statement commons schemas params common)
1052+ (Path (CommonTableExpression statement schemas params) commons commons1) where
1053+ statement `as` cte = csingleton (statement `as` cte)
1054+
1055+instance (forall c s p r. RenderSQL (statement c s p r)) => RenderSQL
1056+ (CommonTableExpression statement schemas params commons0 commons1) where
1057+ renderSQL (CommonTableExpression (statement `As` cte)) =
1058+ renderSQL cte <+> "AS" <+> parenthesized (renderSQL statement)
1059+
1060+-- | `with` provides a way to write auxiliary statements for use in a larger query.
1061+-- These statements, referred to as `CommonTableExpression`s, can be thought of as
1062+-- defining temporary tables that exist just for one query.
1063+class With statement where
1064+ with
1065+ :: Path (CommonTableExpression statement schemas params) commons0 commons1
1066+ -- ^ common table expressions
1067+ -> statement commons1 schemas params row
1068+ -- ^ larger query
1069+ -> statement commons0 schemas params row
1070+instance With (Query outer) where
1071+ with Done query = query
1072+ with ctes query = UnsafeQuery $
1073+ "WITH" <+> commaSeparated (ctoList renderSQL ctes) <+> renderSQL query
7611074
762−-- | `SortExpression`s are used by `sortBy` to optionally sort the results
763−-- of a `Query`. `Asc` or `Desc` set the sort direction of a `NotNull` result
764−-- column to ascending or descending. Ascending order puts smaller values
765−-- first, where "smaller" is defined in terms of the `.<` operator. Similarly,
766−-- descending order is determined with the `.>` operator. `AscNullsFirst`,
767−-- `AscNullsLast`, `DescNullsFirst` and `DescNullsLast` options are used to
768−-- determine whether nulls appear before or after non-null values in the sort
769−-- ordering of a `Null` result column.
770−data SortExpression tables grouping params where
771− Asc
772− :: Expression tables grouping params ('NotNull ty)
773− -> SortExpression tables grouping params
774− Desc
775− :: Expression tables grouping params ('NotNull ty)
776− -> SortExpression tables grouping params
777− AscNullsFirst
778− :: Expression tables grouping params ('Null ty)
779− -> SortExpression tables grouping params
780− AscNullsLast
781− :: Expression tables grouping params ('Null ty)
782− -> SortExpression tables grouping params
783− DescNullsFirst
784− :: Expression tables grouping params ('Null ty)
785− -> SortExpression tables grouping params
786− DescNullsLast
787− :: Expression tables grouping params ('Null ty)
788− -> SortExpression tables grouping params
789−deriving instance Show (SortExpression tables grouping params)
790−
791−-- | Render a `SortExpression`.
792−renderSortExpression :: SortExpression tables grouping params -> ByteString
793−renderSortExpression = \case
794− Asc expression -> renderExpression expression <+> "ASC"
795− Desc expression -> renderExpression expression <+> "DESC"
796− AscNullsFirst expression -> renderExpression expression
797− <+> "ASC NULLS FIRST"
798− DescNullsFirst expression -> renderExpression expression
799− <+> "DESC NULLS FIRST"
800− AscNullsLast expression -> renderExpression expression <+> "ASC NULLS LAST"
801− DescNullsLast expression -> renderExpression expression <+> "DESC NULLS LAST"
1075+{- |
1076+>>> import Data.Monoid (Sum (..))
1077+>>> import Data.Int (Int64)
1078+>>> :{
1079+ let
1080+ query :: Query_ schema () (Sum Int64)
1081+ query = withRecursive
1082+ ( values_ ((1 & astype int) `as` #n)
1083+ `unionAll`
1084+ select_ ((#n + 1) `as` #n)
1085+ (from (common #t) & where_ (#n .< 100)) `as` #t )
1086+ ( select_ (fromNull 0 (sum_ (All #n)) `as` #getSum) (from (common #t) & groupBy Nil))
1087+ in printSQL query
1088+:}
1089+WITH RECURSIVE "t" AS ((SELECT * FROM (VALUES ((1 :: int))) AS t ("n")) UNION ALL (SELECT ("n" + 1) AS "n" FROM "t" AS "t" WHERE ("n" < 100))) SELECT COALESCE(sum(ALL "n"), 0) AS "getSum" FROM "t" AS "t"
1090+-}
1091+withRecursive
1092+ :: Aliased (Query outer (recursive ': commons) schemas params) recursive
1093+ -> Query outer (recursive ': commons) schemas params row
1094+ -> Query outer commons schemas params row
1095+withRecursive (recursive `As` cte) query = UnsafeQuery $
1096+ "WITH RECURSIVE" <+> renderSQL cte
1097+ <+> "AS" <+> parenthesized (renderSQL recursive)
1098+ <+> renderSQL query
squeal-postgresql/src/Squeal/PostgreSQL/Render.hsnew file+145
@@ -0,0 +1,145 @@
1+{-|
2+Module: Squeal.PostgreSQL.Render
3+Description: Rendering helper functions
4+Copyright: (c) Eitan Chatav, 2017
5+Maintainer: eitan@morphism.tech
6+Stability: experimental
7+
8+Rendering helper functions.
9+-}
10+
11+{-# LANGUAGE
12+ AllowAmbiguousTypes
13+ , ConstraintKinds
14+ , FlexibleContexts
15+ , LambdaCase
16+ , MagicHash
17+ , OverloadedStrings
18+ , PolyKinds
19+ , RankNTypes
20+ , ScopedTypeVariables
21+ , TypeApplications
22+#-}
23+
24+module Squeal.PostgreSQL.Render
25+ ( -- * Render
26+ RenderSQL (..)
27+ , printSQL
28+ , escape
29+ , parenthesized
30+ , bracketed
31+ , (<+>)
32+ , commaSeparated
33+ , doubleQuoted
34+ , singleQuotedText
35+ , singleQuotedUtf8
36+ , renderCommaSeparated
37+ , renderCommaSeparatedConstraint
38+ , renderCommaSeparatedMaybe
39+ , renderNat
40+ , renderSymbol
41+ ) where
42+
43+import Control.Monad.IO.Class (MonadIO (..))
44+import Data.ByteString (ByteString)
45+import Data.Maybe (catMaybes)
46+import Data.Monoid ((<>))
47+import Data.Text (Text)
48+import Generics.SOP
49+import GHC.Exts
50+import GHC.TypeLits hiding (Text)
51+
52+import qualified Data.Text as Text
53+import qualified Data.Text.Encoding as Text
54+import qualified Data.ByteString as ByteString
55+import qualified Data.ByteString.Char8 as Char8
56+
57+-- | Parenthesize a `ByteString`.
58+parenthesized :: ByteString -> ByteString
59+parenthesized str = "(" <> str <> ")"
60+
61+-- | Square bracket a `ByteString`
62+bracketed :: ByteString -> ByteString
63+bracketed str = "[" <> str <> "]"
64+
65+-- | Concatenate two `ByteString`s with a space between.
66+(<+>) :: ByteString -> ByteString -> ByteString
67+infixr 7 <+>
68+str1 <+> str2 = str1 <> " " <> str2
69+
70+-- | Comma separate a list of `ByteString`s.
71+commaSeparated :: [ByteString] -> ByteString
72+commaSeparated = ByteString.intercalate ", "
73+
74+-- | Add double quotes around a `ByteString`.
75+doubleQuoted :: ByteString -> ByteString
76+doubleQuoted str = "\"" <> str <> "\""
77+
78+-- | Add single quotes around a `Text` and escape single quotes within it.
79+singleQuotedText :: Text -> ByteString
80+singleQuotedText str =
81+ "'" <> Text.encodeUtf8 (Text.replace "'" "''" str) <> "'"
82+
83+-- | Add single quotes around a `ByteString` and escape single quotes within it.
84+singleQuotedUtf8 :: ByteString -> ByteString
85+singleQuotedUtf8 = singleQuotedText . Text.decodeUtf8
86+
87+-- | Comma separate the renderings of a heterogeneous list.
88+renderCommaSeparated
89+ :: SListI xs
90+ => (forall x. expression x -> ByteString)
91+ -> NP expression xs -> ByteString
92+renderCommaSeparated render
93+ = commaSeparated
94+ . hcollapse
95+ . hmap (K . render)
96+
97+-- | Comma separate the renderings of a heterogeneous list.
98+renderCommaSeparatedConstraint
99+ :: forall c xs expression. (All c xs, SListI xs)
100+ => (forall x. c x => expression x -> ByteString)
101+ -> NP expression xs -> ByteString
102+renderCommaSeparatedConstraint render
103+ = commaSeparated
104+ . hcollapse
105+ . hcmap (Proxy @c) (K . render)
106+
107+-- | Comma separate the `Maybe` renderings of a heterogeneous list, dropping
108+-- `Nothing`s.
109+renderCommaSeparatedMaybe
110+ :: SListI xs
111+ => (forall x. expression x -> Maybe ByteString)
112+ -> NP expression xs -> ByteString
113+renderCommaSeparatedMaybe render
114+ = commaSeparated
115+ . catMaybes
116+ . hcollapse
117+ . hmap (K . render)
118+
119+-- | Render a promoted `Nat`.
120+renderNat :: forall n. KnownNat n => ByteString
121+renderNat = fromString (show (natVal' (proxy# :: Proxy# n)))
122+
123+-- | Render a promoted `Symbol`.
124+renderSymbol :: forall s. KnownSymbol s => ByteString
125+renderSymbol = fromString (symbolVal' (proxy# :: Proxy# s))
126+
127+-- | A class for rendering SQL
128+class RenderSQL sql where renderSQL :: sql -> ByteString
129+
130+-- | Print SQL.
131+printSQL :: (RenderSQL sql, MonadIO io) => sql -> io ()
132+printSQL = liftIO . Char8.putStrLn . renderSQL
133+
134+-- | `escape` a character to prevent injection
135+escape :: Char -> String
136+escape = \case
137+ '\NUL' -> "\\0"
138+ '\'' -> "''"
139+ '"' -> "\\\""
140+ '\b' -> "\\b"
141+ '\n' -> "\\n"
142+ '\r' -> "\\r"
143+ '\t' -> "\\t"
144+ '\\' -> "\\\\"
145+ c -> [c]
squeal-postgresql/src/Squeal/PostgreSQL/Schema.hs+448−262
@@ -1,103 +1,120 @@
11{-|
22Module: Squeal.PostgreSQL.Schema
33Description: Embedding of PostgreSQL type and alias system
4−Copyright: (c) Eitan Chatav, 2017
4+Copyright: (c) Eitan Chatav, 2019
55Maintainer: eitan@morphism.tech
66Stability: experimental
77
8−Embedding of PostgreSQL type and alias system
8+`Squeal.PostgreSQL.Schema` provides a type-level DSL for kinds of Postgres types,
9+tables, schema, constraints, aliases, enumerated labels, and groupings.
10+It also defines useful type families to operate on these. Finally,
11+it defines an embedding of Haskell types into Postgres types.
912-}
10−
1113{-# LANGUAGE
12− ConstraintKinds
13− , DataKinds
14+ AllowAmbiguousTypes
15+ , ConstraintKinds
1416 , DeriveAnyClass
15− , DeriveDataTypeable
1617 , DeriveGeneric
1718 , FlexibleContexts
1819 , FlexibleInstances
1920 , FunctionalDependencies
2021 , GADTs
21− , MagicHash
22− , MultiParamTypeClasses
22+ , LambdaCase
2323 , OverloadedStrings
24− , PolyKinds
24+ , QuantifiedConstraints
2525 , RankNTypes
2626 , ScopedTypeVariables
2727 , StandaloneDeriving
2828 , TypeApplications
29− , TypeFamilies
29+ , TypeFamilyDependencies
3030 , TypeInType
3131 , TypeOperators
3232 , UndecidableInstances
33+ , UndecidableSuperClasses
3334#-}
3435
3536module Squeal.PostgreSQL.Schema
36− ( -- * Kinds
37+ ( -- * Postgres Types
3738 PGType (..)
3839 , NullityType (..)
40+ , RowType
41+ , FromType
42+ -- * Schema Types
3943 , ColumnType
4044 , ColumnsType
41− , RelationType
42− , RelationsType
4345 , TableType
44− , TablesType
45− , Grouping (..)
46− -- * PostgreSQL Constraints
46+ , SchemumType (..)
47+ , IndexType (..)
48+ , FunctionType
49+ , OperatorType (..)
50+ , ReturnsType (..)
51+ , SchemaType
52+ , SchemasType
53+ , Public
54+ -- * Constraints
4755 , (:=>)
48− , ColumnsToRelation
49− , TableToColumns
50− , TablesToRelations
5156 , ColumnConstraint (..)
5257 , TableConstraint (..)
53− -- * AliasesOf
54− , (:::)
55− , Alias (Alias)
56− , renderAlias
57− , Aliased (As)
58− , renderAliasedAs
59− , AliasesOf
60− , Has
61− , HasUnique
62− , IsLabel (..)
63− , IsTableColumn (..)
64− -- * Type Families
65− , In
58+ , TableConstraints
59+ , Uniquely
60+ -- * Enumerated Labels
61+ , IsPGlabel (..)
62+ , PGlabel (..)
63+ -- * Data Definitions
64+ , Create
65+ , CreateIfNotExists
66+ , CreateOrReplace
67+ , Drop
68+ , DropSchemum
69+ , DropIfExists
70+ , DropSchemumIfExists
71+ , Alter
72+ , AlterIfExists
73+ , Rename
74+ , RenameIfExists
75+ , ConstraintInvolves
76+ , DropIfConstraintsInvolve
77+ , IsNotElem
78+ , AllUnique
79+ -- * Type Classifications
6680 , PGNum
6781 , PGIntegral
6882 , PGFloating
6983 , PGTypeOf
70− , SameTypes
84+ , PGJsonType
85+ , PGJsonKey
86+ , SamePGType
7187 , AllNotNull
7288 , NotAllNull
89+ -- * Nullifications
7390 , NullifyType
74− , NullifyColumns
75− , NullifyTables
76− , Join
77− , Create
78− , AddColumn
79− , AddConstraint
80− , Drop
81− , Alter
82− , Rename
83− -- * Generics
84− , SameField
85− , SameFields
91+ , NullifyRow
92+ , NullifyFrom
93+ -- * Table Conversions
94+ , TableToColumns
95+ , ColumnsToRow
96+ , TableToRow
8697 ) where
8798
88−import Control.DeepSeq
89−import Data.ByteString
90−import Data.Monoid
91−import Data.String
92−import Generics.SOP (AllZip)
93−import GHC.Generics (Generic)
94−import GHC.Exts
95−import GHC.OverloadedLabels
99+import Control.Category
100+import Data.Kind
101+import Data.Monoid hiding (All)
102+import Data.Type.Bool
103+import Generics.SOP
96104import GHC.TypeLits
105+import Prelude hiding (id, (.))
106+
107+import Squeal.PostgreSQL.Alias
108+import Squeal.PostgreSQL.List
109+import Squeal.PostgreSQL.Render
97110
98−import qualified Generics.SOP.Type.Metadata as Type
111+-- $setup
112+-- >>> import Squeal.PostgreSQL
99113
100114-- | `PGType` is the promoted datakind of PostgreSQL types.
115+--
116+-- >>> :kind 'PGbool
117+-- 'PGbool :: PGType
101118data PGType
102119 = PGbool -- ^ logical Boolean (true/false)
103120 | PGint2 -- ^ signed two-byte integer
@@ -106,6 +123,7 @@ data PGType
106123 | PGnumeric -- ^ arbitrary precision numeric type
107124 | PGfloat4 -- ^ single precision floating-point number (4 bytes)
108125 | PGfloat8 -- ^ double precision floating-point number (8 bytes)
126+ | PGmoney -- ^ currency amount
109127 | PGchar Nat -- ^ fixed-length character string
110128 | PGvarchar Nat -- ^ variable-length character string
111129 | PGtext -- ^ variable-length character string
@@ -120,291 +138,459 @@ data PGType
120138 | PGinet -- ^ IPv4 or IPv6 host address
121139 | PGjson -- ^ textual JSON data
122140 | PGjsonb -- ^ binary JSON data, decomposed
141+ | PGvararray NullityType -- ^ variable length array
142+ | PGfixarray [Nat] NullityType -- ^ fixed length array
143+ | PGenum [Symbol] -- ^ enumerated (enum) types are data types that comprise a static, ordered set of values.
144+ | PGcomposite RowType -- ^ a composite type represents the structure of a row or record; it is essentially just a list of field names and their data types.
145+ | PGtsvector -- ^ A tsvector value is a sorted list of distinct lexemes, which are words that have been normalized to merge different variants of the same word.
146+ | PGtsquery -- ^ A tsquery value stores lexemes that are to be searched for.
147+ | PGoid -- Object identifiers (OIDs) are used internally by PostgreSQL as primary keys for various system tables.
148+ | PGrange PGType -- ^ Range types are data types representing a range of values of some element type (called the range's subtype).
123149 | UnsafePGType Symbol -- ^ an escape hatch for unsupported PostgreSQL types
124150
125151-- | `NullityType` encodes the potential presence or definite absence of a
126152-- @NULL@ allowing operations which are sensitive to such to be well typed.
153+--
154+-- >>> :kind 'Null 'PGint4
155+-- 'Null 'PGint4 :: NullityType
156+-- >>> :kind 'NotNull ('PGvarchar 50)
157+-- 'NotNull ('PGvarchar 50) :: NullityType
127158data NullityType
128159 = Null PGType -- ^ @NULL@ may be present
129160 | NotNull PGType -- ^ @NULL@ is absent
130161
131−-- | `:=>` is a type level pair between an "constraint" and some type,
132−-- either a `ColumnConstraint` and a `NullityType` or a row of
133−-- `TableConstraint`s and a `TableType`.
162+-- | The constraint operator, `:=>` is a type level pair
163+-- between a "constraint" and some type, for use in pairing
164+-- a `ColumnConstraint` with a `NullityType` to produce a `ColumnType`
165+-- or a `TableConstraints` and a `ColumnsType` to produce a `TableType`.
134166type (:=>) constraint ty = '(constraint,ty)
135167infixr 7 :=>
136168
137−-- | `:::` is like a promoted version of `As`, a type level pair between
138−-- an alias and some type, like a column alias and either a `ColumnType` or
139−-- `NullityType` or a table alias and either a `TableType` or a `RelationType`
140−-- or a constraint alias and a `TableConstraint`.
141−type (:::) (alias :: Symbol) ty = '(alias,ty)
142−infixr 6 :::
143−
144−-- | `ColumnConstraint` encodes the allowance of @DEFAULT@.
169+-- | `ColumnConstraint` encodes the availability of @DEFAULT@ for inserts and updates.
170+-- A column can be assigned a default value.
171+-- A data `Squeal.PostgreSQL.Manipulations.Manipulation` command can also
172+-- request explicitly that a column be set to its default value,
173+-- without having to know what that value is.
145174data ColumnConstraint
146175 = Def -- ^ @DEFAULT@ is available for inserts and updates
147176 | NoDef -- ^ @DEFAULT@ is unavailable for inserts and updates
148177
149178-- | `ColumnType` encodes the allowance of @DEFAULT@ and @NULL@ and the
150179-- base `PGType` for a column.
180+--
181+-- >>> :set -XTypeFamilies -XTypeInType
182+-- >>> import GHC.TypeLits
183+-- >>> type family IdColumn :: ColumnType where IdColumn = 'Def :=> 'NotNull 'PGint4
184+-- >>> type family EmailColumn :: ColumnType where EmailColumn = 'NoDef :=> 'Null 'PGtext
151185type ColumnType = (ColumnConstraint,NullityType)
152186
153187-- | `ColumnsType` is a row of `ColumnType`s.
188+--
189+-- >>> :{
190+-- type family UsersColumns :: ColumnsType where
191+-- UsersColumns =
192+-- '[ "name" ::: 'NoDef :=> 'NotNull 'PGtext
193+-- , "id" ::: 'Def :=> 'NotNull 'PGint4
194+-- ]
195+-- :}
154196type ColumnsType = [(Symbol,ColumnType)]
155197
156198-- | `TableConstraint` encodes various forms of data constraints
157199-- of columns in a table.
200+-- `TableConstraint`s give you as much control over the data in your tables
201+-- as you wish. If a user attempts to store data in a column that would
202+-- violate a constraint, an error is raised. This applies
203+-- even if the value came from the default value definition.
158204data TableConstraint
159− = Check
205+ = Check [Symbol]
160206 | Unique [Symbol]
161207 | PrimaryKey [Symbol]
162208 | ForeignKey [Symbol] Symbol [Symbol]
163209
164−-- | `TableType` encodes a row of constraints on a table as well as the types
165−-- of its columns.
166−type TableType = ([(Symbol,TableConstraint)],ColumnsType)
210+{- | A `TableConstraints` is a row of `TableConstraint`s.
167211
168−-- | `TablesType` is a row of `TableType`s, thought of as a union.
169−type TablesType = [(Symbol,TableType)]
212+>>> :{
213+type family UsersConstraints :: TableConstraints where
214+ UsersConstraints = '[ "pk_users" ::: 'PrimaryKey '["id"] ]
215+:}
216+-}
217+type TableConstraints = [(Symbol,TableConstraint)]
170218
171−-- | `RelationType` is a row of `NullityType`
172−type RelationType = [(Symbol,NullityType)]
219+-- | A `ForeignKey` must reference columns that either are
220+-- a `PrimaryKey` or form a `Unique` constraint.
221+type family Uniquely
222+ (key :: [Symbol])
223+ (constraints :: TableConstraints) :: Constraint where
224+ Uniquely key (uq ::: 'Unique key ': constraints) = ()
225+ Uniquely key (pk ::: 'PrimaryKey key ': constraints) = ()
226+ Uniquely key (_ ': constraints) = Uniquely key constraints
173227
174−-- | `RelationsType` is a row of `RelationType`s, thought of as a product.
175−type RelationsType = [(Symbol,RelationType)]
228+-- | `TableType` encodes a row of constraints on a table as well as the types
229+-- of its columns.
230+--
231+-- >>> :{
232+-- type family UsersTable :: TableType where
233+-- UsersTable =
234+-- '[ "pk_users" ::: 'PrimaryKey '["id"] ] :=>
235+-- '[ "id" ::: 'Def :=> 'NotNull 'PGint4
236+-- , "name" ::: 'NoDef :=> 'NotNull 'PGtext
237+-- ]
238+-- :}
239+type TableType = (TableConstraints,ColumnsType)
240+
241+{- | A `RowType` is a row of `NullityType`. They correspond to Haskell
242+record types by means of `Squeal.PostgreSQL.Binary.RowPG` and are used in many places.
243+
244+>>> :{
245+type family PersonRow :: RowType where
246+ PersonRow =
247+ '[ "name" ::: 'NotNull 'PGtext
248+ , "age" ::: 'NotNull 'PGint4
249+ , "dateOfBirth" ::: 'Null 'PGdate
250+ ]
251+:}
252+-}
253+type RowType = [(Symbol,NullityType)]
176254
177−-- | `ColumnsToRelation` removes column constraints.
178−type family ColumnsToRelation (columns :: ColumnsType) :: RelationType where
179− ColumnsToRelation '[] = '[]
180− ColumnsToRelation (column ::: constraint :=> ty ': columns) =
181− column ::: ty ': ColumnsToRelation columns
255+{- | `FromType` is a row of `RowType`s. It can be thought of as
256+a product, or horizontal gluing and is used in `Squeal.PostgreSQL.Query.FromClause`s
257+and `Squeal.PostgreSQL.Query.TableExpression`s.
258+-}
259+type FromType = [(Symbol,RowType)]
260+
261+-- | `ColumnsToRow` removes column constraints.
262+type family ColumnsToRow (columns :: ColumnsType) :: RowType where
263+ ColumnsToRow (column ::: _ :=> ty ': column1 ::: _ :=> ty1 ': column2 ::: _ :=> ty2 ': column3 ::: _ :=> ty3 ': column4 ::: _ :=> ty4 ': column5 ::: _ :=> ty5 ': columns) =
264+ column ::: ty ': column1 ::: ty1 ': column2 ::: ty2 ': column3 ::: ty3 ': column4 ::: ty4 ': column5 ::: ty5 ': ColumnsToRow columns
265+ ColumnsToRow (column ::: _ :=> ty ': column1 ::: _ :=> ty1 ': column2 ::: _ :=> ty2 ': column3 ::: _ :=> ty3 ': column4 ::: _ :=> ty4 ': columns) =
266+ column ::: ty ': column1 ::: ty1 ': column2 ::: ty2 ': column3 ::: ty3 ': column4 ::: ty4 ': ColumnsToRow columns
267+ ColumnsToRow (column ::: _ :=> ty ': column1 ::: _ :=> ty1 ': column2 ::: _ :=> ty2 ': column3 ::: _ :=> ty3 ': columns) =
268+ column ::: ty ': column1 ::: ty1 ': column2 ::: ty2 ': column3 ::: ty3 ': ColumnsToRow columns
269+ ColumnsToRow (column ::: _ :=> ty ': column1 ::: _ :=> ty1 ': column2 ::: _ :=> ty2 ': columns) =
270+ column ::: ty ': column1 ::: ty1 ': column2 ::: ty2 ': ColumnsToRow columns
271+ ColumnsToRow (column ::: _ :=> ty ': column1 ::: _ :=> ty1 ': columns) =
272+ column ::: ty ': column1 ::: ty1 ': ColumnsToRow columns
273+ ColumnsToRow (column ::: _ :=> ty ': columns) =
274+ column ::: ty ': ColumnsToRow columns
275+ ColumnsToRow '[] = '[]
182276
183277-- | `TableToColumns` removes table constraints.
184278type family TableToColumns (table :: TableType) :: ColumnsType where
185279 TableToColumns (constraints :=> columns) = columns
186280
187−-- | `TablesToRelations` removes both table and column constraints.
188−type family TablesToRelations (tables :: TablesType) :: RelationsType where
189− TablesToRelations '[] = '[]
190− TablesToRelations (alias ::: constraint :=> columns ': tables) =
191− alias ::: ColumnsToRelation columns ': TablesToRelations tables
192−
193−-- | `Grouping` is an auxiliary namespace, created by
194−-- @GROUP BY@ clauses (`Squeal.PostgreSQL.Query.group`), and used
195−-- for typesafe aggregation
196−data Grouping
197− = Ungrouped -- ^ no aggregation permitted
198− | Grouped [(Symbol,Symbol)] -- ^ aggregation required for any column which is not grouped
199−
200−-- | `Alias`es are proxies for a type level string or `Symbol`
201−-- and have an `IsLabel` instance so that with @-XOverloadedLabels@
202−--
203−-- >>> :set -XOverloadedLabels
204−-- >>> #foobar :: Alias "foobar"
205−-- Alias
206−data Alias (alias :: Symbol) = Alias
207− deriving (Eq,Generic,Ord,Show,NFData)
208−instance alias1 ~ alias2 => IsLabel alias1 (Alias alias2) where
209− fromLabel = Alias
210−
211−-- | >>> renderAlias #jimbob
212−-- "jimbob"
213−renderAlias :: KnownSymbol alias => Alias alias -> ByteString
214−renderAlias = fromString . symbolVal
215−
216−-- | The `As` operator is used to name an expression. `As` is like a demoted
217−-- version of `:::`.
218−--
219−-- >>> Just "hello" `As` #hi :: Aliased Maybe ("hi" ::: String)
220−-- As (Just "hello") Alias
221−data Aliased expression aliased where
222− As
223− :: KnownSymbol alias
224− => expression ty
225− -> Alias alias
226− -> Aliased expression (alias ::: ty)
227−deriving instance Show (expression ty)
228− => Show (Aliased expression (alias ::: ty))
229−deriving instance Eq (expression ty)
230− => Eq (Aliased expression (alias ::: ty))
231−deriving instance Ord (expression ty)
232− => Ord (Aliased expression (alias ::: ty))
233−instance KnownSymbol alias
234− => IsLabel alias (expression ty -> Aliased expression (alias ::: ty))
235− where fromLabel expression = expression `As` Alias @alias
236−
237−-- | >>> let renderMaybe = fromString . maybe "Nothing" (const "Just")
238−-- >>> renderAliasedAs renderMaybe (Just (3::Int) `As` #an_int)
239−-- "Just AS an_int"
240−renderAliasedAs
241− :: (forall ty. expression ty -> ByteString)
242− -> Aliased expression aliased
243− -> ByteString
244−renderAliasedAs render (expression `As` alias) =
245− render expression <> " AS " <> renderAlias alias
246−
247−-- | `AliasesOf` retains the AliasesOf in a row.
248−type family AliasesOf aliaseds where
249− AliasesOf '[] = '[]
250− AliasesOf (alias ::: ty ': tys) = alias ': AliasesOf tys
251−
252−-- | @HasUnique alias xs x@ is a constraint that proves that @xs@ is a singleton
253−-- of @alias ::: x@.
254−type HasUnique alias xs x = xs ~ '[alias ::: x]
255−
256−-- | @Has alias xs x@ is a constraint that proves that @xs@ has a field
257−-- of @alias ::: x@.
258−class KnownSymbol alias =>
259− Has (alias :: Symbol) (fields :: [(Symbol,kind)]) (field :: kind)
260− | alias fields -> field where
261−instance {-# OVERLAPPING #-} KnownSymbol alias
262− => Has alias (alias ::: field ': fields) field
263−instance {-# OVERLAPPABLE #-} (KnownSymbol alias, Has alias fields field)
264− => Has alias (field' ': fields) field
265−
266−-- | Analagous to `IsLabel`, the constraint
267−-- `IsTableColumn` defines `!` for a column alias qualified
268−-- by a table alias.
269−class IsTableColumn table column expression where
270− (!) :: Alias table -> Alias column -> expression
271− infixl 9 !
272−instance IsTableColumn table column (Alias table, Alias column) where (!) = (,)
273−
274−-- | @In x xs@ is a constraint that proves that @x@ is in @xs@.
275−type family In x xs :: Constraint where
276− In x (x ': xs) = ()
277− In x (y ': xs) = In x xs
278−
279−-- | `PGNum` is a constraint on `PGType` whose
280−-- `Squeal.PostgreSQL.Expression.Expression`s have a `Num` constraint.
281−type PGNum ty =
282− In ty '[ 'PGint2, 'PGint4, 'PGint8, 'PGnumeric, 'PGfloat4, 'PGfloat8]
283−
284−-- | `PGFloating` is a constraint on `PGType` whose
285−-- `Squeal.PostgreSQL.Expression.Expression`s
286−-- have `Fractional` and `Floating` constraints.
287−type PGFloating ty = In ty '[ 'PGfloat4, 'PGfloat8, 'PGnumeric]
288−
289−-- | `PGIntegral` is a constraint on `PGType` whose
290−-- `Squeal.PostgreSQL.Expression.Expression`s
291−-- have `Squeal.PostgreSQL.Expression.div_` and
292−-- `Squeal.PostgreSQL.Expression.mod_` functions.
293−type PGIntegral ty = In ty '[ 'PGint2, 'PGint4, 'PGint8]
281+-- | Convert a table to a row type.
282+type family TableToRow (table :: TableType) :: RowType where
283+ TableToRow tab = ColumnsToRow (TableToColumns tab)
284+
285+-- | Numeric Postgres types.
286+type PGNum =
287+ '[ 'PGint2, 'PGint4, 'PGint8, 'PGnumeric, 'PGfloat4, 'PGfloat8]
288+
289+-- | Floating Postgres types.
290+type PGFloating = '[ 'PGfloat4, 'PGfloat8, 'PGnumeric]
291+
292+-- | Integral Postgres types.
293+type PGIntegral = '[ 'PGint2, 'PGint4, 'PGint8]
294294
295295-- | `PGTypeOf` forgets about @NULL@ and any column constraints.
296296type family PGTypeOf (ty :: NullityType) :: PGType where
297297 PGTypeOf (nullity pg) = pg
298298
299−-- | `SameTypes` is a constraint that proves two `ColumnsType`s have the same
300−-- length and the same `ColumnType`s.
301−type family SameTypes (columns0 :: ColumnsType) (columns1 :: ColumnsType)
302− :: Constraint where
303− SameTypes '[] '[] = ()
304− SameTypes (column0 ::: def0 :=> ty0 ': columns0) (column1 ::: def1 :=> ty1 ': columns1)
305− = (ty0 ~ ty1, SameTypes columns0 columns1)
299+-- | Equality constraint on the underlying `PGType` of two columns.
300+class SamePGType
301+ (ty0 :: (Symbol,ColumnType)) (ty1 :: (Symbol,ColumnType)) where
302+instance ty0 ~ ty1 => SamePGType
303+ (alias0 ::: def0 :=> nullity0 ty0)
304+ (alias1 ::: def1 :=> nullity1 ty1)
306305
307306-- | `AllNotNull` is a constraint that proves a `ColumnsType` has no @NULL@s.
308307type family AllNotNull (columns :: ColumnsType) :: Constraint where
308+ AllNotNull (_ ::: _ :=> 'NotNull _ ': _ ::: _ :=> 'NotNull _ ': _ ::: _ :=> 'NotNull _ ': _ ::: _ :=> 'NotNull _ ': _ ::: _ :=> 'NotNull _ ': _ ::: _ :=> 'NotNull _ ': columns) = AllNotNull columns
309+ AllNotNull (_ ::: _ :=> 'NotNull _ ': _ ::: _ :=> 'NotNull _ ': _ ::: _ :=> 'NotNull _ ': _ ::: _ :=> 'NotNull _ ': _ ::: _ :=> 'NotNull _ ': columns) = AllNotNull columns
310+ AllNotNull (_ ::: _ :=> 'NotNull _ ': _ ::: _ :=> 'NotNull _ ': _ ::: _ :=> 'NotNull _ ': _ ::: _ :=> 'NotNull _ ': columns) = AllNotNull columns
311+ AllNotNull (_ ::: _ :=> 'NotNull _ ': _ ::: _ :=> 'NotNull _ ': _ ::: _ :=> 'NotNull _ ': columns) = AllNotNull columns
312+ AllNotNull (_ ::: _ :=> 'NotNull _ ': _ ::: _ :=> 'NotNull _ ': columns) = AllNotNull columns
313+ AllNotNull (_ ::: _ :=> 'NotNull _ ': columns) = AllNotNull columns
309314 AllNotNull '[] = ()
310− AllNotNull (column ::: def :=> 'NotNull ty ': columns) = AllNotNull columns
311315
312316-- | `NotAllNull` is a constraint that proves a `ColumnsType` has some
313317-- @NOT NULL@.
314318type family NotAllNull (columns :: ColumnsType) :: Constraint where
315− NotAllNull (column ::: def :=> 'NotNull ty ': columns) = ()
316− NotAllNull (column ::: def :=> 'Null ty ': columns) = NotAllNull columns
317−
318−-- | `NullifyType` is an idempotent that nullifies a `ColumnType`.
319+ NotAllNull (_ ::: _ :=> _ _ ': _ ::: _ :=> _ _ ': _ ::: _ :=> _ _ ': _ ::: _ :=> _ _ ': _ ::: _ :=> _ _ ': _ ::: _ :=> 'NotNull _ ': _) = ()
320+ NotAllNull (_ ::: _ :=> _ _ ': _ ::: _ :=> _ _ ': _ ::: _ :=> _ _ ': _ ::: _ :=> _ _ ': _ ::: _ :=> 'NotNull _ ': _) = ()
321+ NotAllNull (_ ::: _ :=> _ _ ': _ ::: _ :=> _ _ ': _ ::: _ :=> _ _ ': _ ::: _ :=> 'NotNull _ ': _) = ()
322+ NotAllNull (_ ::: _ :=> _ _ ': _ ::: _ :=> _ _ ': _ ::: _ :=> 'NotNull _ ': _) = ()
323+ NotAllNull (_ ::: _ :=> _ _ ': _ ::: _ :=> 'NotNull _ ': _) = ()
324+ NotAllNull (_ ::: _ :=> 'NotNull _ ': _) = ()
325+ NotAllNull (_ ::: _ :=> 'Null _ ': columns) = NotAllNull columns
326+
327+-- | `NullifyType` is an idempotent that nullifies a `NullityType`.
319328type family NullifyType (ty :: NullityType) :: NullityType where
320329 NullifyType ('Null ty) = 'Null ty
321330 NullifyType ('NotNull ty) = 'Null ty
322331
323−-- | `NullifyColumns` is an idempotent that nullifies a `ColumnsType`.
324−type family NullifyColumns (columns :: RelationType) :: RelationType where
325− NullifyColumns '[] = '[]
326− NullifyColumns (column ::: ty ': columns) =
327− column ::: NullifyType ty ': NullifyColumns columns
328−
329−-- | `NullifyTables` is an idempotent that nullifies a `RelationsType`
332+-- | `NullifyRow` is an idempotent that nullifies a `RowType`.
333+type family NullifyRow (columns :: RowType) :: RowType where
334+ NullifyRow (column ::: ty ': column1 ::: ty1 ': column2 ::: ty2 ': column3 ::: ty3 ': column4 ::: ty4 ': column5 ::: ty5 ': columns) =
335+ column ::: NullifyType ty ': column1 ::: NullifyType ty1 ': column2 ::: NullifyType ty2 ': column3 ::: NullifyType ty3 ': column4 ::: NullifyType ty4 ': column5 ::: NullifyType ty5 ': NullifyRow columns
336+ NullifyRow (column ::: ty ': column1 ::: ty1 ': column2 ::: ty2 ': column3 ::: ty3 ': column4 ::: ty4 ': columns) =
337+ column ::: NullifyType ty ': column1 ::: NullifyType ty1 ': column2 ::: NullifyType ty2 ': column3 ::: NullifyType ty3 ': column4 ::: NullifyType ty4 ': NullifyRow columns
338+ NullifyRow (column ::: ty ': column1 ::: ty1 ': column2 ::: ty2 ': column3 ::: ty3 ': columns) =
339+ column ::: NullifyType ty ': column1 ::: NullifyType ty1 ': column2 ::: NullifyType ty2 ': column3 ::: NullifyType ty3 ': NullifyRow columns
340+ NullifyRow (column ::: ty ': column1 ::: ty1 ': column2 ::: ty2 ': columns) =
341+ column ::: NullifyType ty ': column1 ::: NullifyType ty1 ': column2 ::: NullifyType ty2 ': NullifyRow columns
342+ NullifyRow (column ::: ty ': column1 ::: ty1 ': columns) =
343+ column ::: NullifyType ty ': column1 ::: NullifyType ty1 ': NullifyRow columns
344+ NullifyRow (column ::: ty ': columns) =
345+ column ::: NullifyType ty ': NullifyRow columns
346+ NullifyRow '[] = '[]
347+
348+-- | `NullifyFrom` is an idempotent that nullifies a `FromType`
330349-- used to nullify the left or right hand side of an outer join
331350-- in a `Squeal.PostgreSQL.Query.FromClause`.
332−type family NullifyTables (tables :: RelationsType) :: RelationsType where
333− NullifyTables '[] = '[]
334− NullifyTables (table ::: columns ': tables) =
335− table ::: NullifyColumns columns ': NullifyTables tables
336−
337−-- | `Join` is simply promoted `++` and is used in @JOIN@s in
338−-- `Squeal.PostgreSQL.Query.FromClause`s.
339−type family Join xs ys where
340− Join '[] ys = ys
341− Join (x ': xs) ys = x ': Join xs ys
351+type family NullifyFrom (tables :: FromType) :: FromType where
352+ NullifyFrom (table ::: columns ': table1 ::: columns1 ': table2 ::: columns2 ': table3 ::: columns3 ': table4 ::: columns4 ': table5 ::: columns5 ': tables) =
353+ table ::: NullifyRow columns ': table1 ::: NullifyRow columns1 ': table2 ::: NullifyRow columns2 ': table3 ::: NullifyRow columns3 ': table4 ::: NullifyRow columns5 ': table5 ::: NullifyRow columns4 ': NullifyFrom tables
354+ NullifyFrom (table ::: columns ': table1 ::: columns1 ': table2 ::: columns2 ': table3 ::: columns3 ': table4 ::: columns4 ': tables) =
355+ table ::: NullifyRow columns ': table1 ::: NullifyRow columns1 ': table2 ::: NullifyRow columns2 ': table3 ::: NullifyRow columns3 ': table4 ::: NullifyRow columns4 ': NullifyFrom tables
356+ NullifyFrom (table ::: columns ': table1 ::: columns1 ': table2 ::: columns2 ': table3 ::: columns3 ': tables) =
357+ table ::: NullifyRow columns ': table1 ::: NullifyRow columns1 ': table2 ::: NullifyRow columns2 ': table3 ::: NullifyRow columns3 ': NullifyFrom tables
358+ NullifyFrom (table ::: columns ': table1 ::: columns1 ': table2 ::: columns2 ': tables) =
359+ table ::: NullifyRow columns ': table1 ::: NullifyRow columns1 ': table2 ::: NullifyRow columns2 ': NullifyFrom tables
360+ NullifyFrom (table ::: columns ': table1 ::: columns1 ': tables) =
361+ table ::: NullifyRow columns ': table1 ::: NullifyRow columns1 ': NullifyFrom tables
362+ NullifyFrom (table ::: columns ': tables) =
363+ table ::: NullifyRow columns ': NullifyFrom tables
364+ NullifyFrom '[] = '[]
342365
343366-- | @Create alias x xs@ adds @alias ::: x@ to the end of @xs@ and is used in
344367-- `Squeal.PostgreSQL.Definition.createTable` statements and in @ALTER TABLE@
345−-- `Squeal.PostgreSQL.Definition.addColumnDefault` and
346−-- `Squeal.PostgreSQL.Definition.addColumnNull` statements.
368+-- `Squeal.PostgreSQL.Definition.addColumn`.
347369type family Create alias x xs where
348370 Create alias x '[] = '[alias ::: x]
371+ Create alias x (alias ::: y ': xs) = TypeError
372+ ('Text "Create: alias "
373+ ':<>: 'ShowType alias
374+ ':<>: 'Text "already exists")
349375 Create alias y (x ': xs) = x ': Create alias y xs
350376
351−type family AddColumn alias x y where
352− AddColumn alias x (constraints :=> xs) = constraints :=> Create alias x xs
353−
354−type family AddConstraint alias x y where
355− AddConstraint alias x (constraints :=> xs) = Create alias x constraints :=> xs
377+type family CreateIfNotExists alias x xs where
378+ CreateIfNotExists alias x '[] = '[alias ::: x]
379+ CreateIfNotExists alias x (alias ::: y ': xs) = alias ::: y ': xs
380+ CreateIfNotExists alias y (x ': xs) = x ': CreateIfNotExists alias y xs
381+
382+type family CreateOrReplace alias x xs where
383+ CreateOrReplace alias x '[] = '[alias ::: x]
384+ CreateOrReplace alias x (alias ::: x ': xs) = alias ::: x ': xs
385+ CreateOrReplace alias x (alias ::: y ': xs) = TypeError
386+ ('Text "CreateOrReplace: expected type "
387+ ':<>: 'ShowType x
388+ ':<>: 'Text " but alias "
389+ ':<>: 'ShowType alias
390+ ':<>: 'Text " has type "
391+ ':<>: 'ShowType y)
392+ CreateOrReplace alias y (x ': xs) = x ': CreateOrReplace alias y xs
356393
357394-- | @Drop alias xs@ removes the type associated with @alias@ in @xs@
358395-- and is used in `Squeal.PostgreSQL.Definition.dropTable` statements
359396-- and in @ALTER TABLE@ `Squeal.PostgreSQL.Definition.dropColumn` statements.
360397type family Drop alias xs where
361− Drop alias ((alias ::: x) ': xs) = xs
398+ Drop alias '[] = TypeError
399+ ('Text "Drop: alias "
400+ ':<>: 'ShowType alias
401+ ':<>: 'Text " does not exist" )
402+ Drop alias (alias ::: x ': xs) = xs
362403 Drop alias (x ': xs) = x ': Drop alias xs
363404
364−-- | @Alter alias xs x@ replaces the type associated with an @alias@ in @xs@
365−-- with the type `x` and is used in `Squeal.PostgreSQL.Definition.alterTable`
405+type family DropSchemum alias sch xs where
406+ DropSchemum alias sch '[] = TypeError
407+ ('Text "DropSchemum: alias "
408+ ':<>: 'ShowType alias
409+ ':<>: 'Text " does not exist" )
410+ DropSchemum alias sch (alias ::: sch x ': xs) = xs
411+ DropSchemum alias sch0 (alias ::: sch1 x ': xs) = TypeError
412+ ('Text "DropSchemum: expected schemum "
413+ ':<>: 'ShowType sch0
414+ ':<>: 'Text " but alias "
415+ ':<>: 'ShowType alias
416+ ':<>: 'Text " has schemum "
417+ ':<>: 'ShowType sch1)
418+ DropSchemum alias sch (x ': xs) = x ': DropSchemum alias sch xs
419+
420+type family DropIfExists alias xs where
421+ DropIfExists alias '[] = '[]
422+ DropIfExists alias (alias ::: x ': xs) = xs
423+ DropIfExists alias (x ': xs) = x ': DropIfExists alias xs
424+
425+type family DropSchemumIfExists alias sch xs where
426+ DropSchemumIfExists alias sch '[] = '[]
427+ DropSchemumIfExists alias sch (alias ::: sch x ': xs) = xs
428+ DropSchemumIfExists alias sch0 (alias ::: sch1 x ': xs) = TypeError
429+ ('Text "DropSchemumIfExists: expected schemum "
430+ ':<>: 'ShowType sch1
431+ ':<>: 'Text " but alias "
432+ ':<>: 'ShowType alias
433+ ':<>: 'Text " has schemum "
434+ ':<>: 'ShowType sch0)
435+ DropSchemumIfExists alias sch (x ': xs) = x ': DropSchemumIfExists alias sch xs
436+
437+-- | @Alter alias x xs@ replaces the type associated with an @alias@ in @xs@
438+-- with the type @x@ and is used in `Squeal.PostgreSQL.Definition.alterTable`
366439-- and `Squeal.PostgreSQL.Definition.alterColumn`.
367−type family Alter alias xs x where
368− Alter alias ((alias ::: x0) ': xs) x1 = (alias ::: x1) ': xs
369− Alter alias (x0 ': xs) x1 = x0 ': Alter alias xs x1
370−
371−-- type family AddConstraint constraint ty where
372−-- AddConstraint constraint (constraints :=> ty)
373−-- = AsSet (constraint ': constraints) :=> ty
374−
375−-- type family DeleteFromList (e :: elem) (list :: [elem]) where
376−-- DeleteFromList elem '[] = '[]
377−-- DeleteFromList elem (x ': xs) =
378−-- If (Cmp elem x == 'EQ) xs (x ': DeleteFromList elem xs)
379−
380−-- type family DropConstraint constraint ty where
381−-- DropConstraint constraint (constraints :=> ty)
382−-- = (AsSet (DeleteFromList constraint constraints)) :=> ty
440+type family Alter alias x xs where
441+ Alter alias x '[] = TypeError
442+ ('Text "Alter: alias "
443+ ':<>: 'ShowType alias
444+ ':<>: 'Text " does not exist" )
445+ Alter alias x1 (alias ::: x0 ': xs) = alias ::: x1 ': xs
446+ Alter alias x1 (x0 ': xs) = x0 ': Alter alias x1 xs
447+
448+type family AlterIfExists alias x xs where
449+ AlterIfExists alias x '[] = '[]
450+ AlterIfExists alias x1 (alias ::: x0 ': xs) = alias ::: x1 ': xs
451+ AlterIfExists alias x1 (x0 ': xs) = x0 ': AlterIfExists alias x1 xs
383452
384453-- | @Rename alias0 alias1 xs@ replaces the alias @alias0@ by @alias1@ in @xs@
385454-- and is used in `Squeal.PostgreSQL.Definition.alterTableRename` and
386455-- `Squeal.PostgreSQL.Definition.renameColumn`.
387456type family Rename alias0 alias1 xs where
457+ Rename alias0 alias1 '[] = TypeError
458+ ('Text "Rename: alias "
459+ ':<>: 'ShowType alias0
460+ ':<>: 'Text " does not exist" )
388461 Rename alias0 alias1 ((alias0 ::: x0) ': xs) = (alias1 ::: x0) ': xs
389462 Rename alias0 alias1 (x ': xs) = x ': Rename alias0 alias1 xs
390463
391−-- | A `SameField` constraint is an equality constraint on a
392−-- `Generics.SOP.Type.Metadata.FieldInfo` and the column alias in a `:::` pair.
393−class SameField
394− (fieldInfo :: Type.FieldInfo) (fieldty :: (Symbol,NullityType)) where
395−instance field ~ column => SameField ('Type.FieldInfo field) (column ::: ty)
396−
397−-- | A `SameFields` constraint proves that a
398−-- `Generics.SOP.Type.Metadata.DatatypeInfo` of a record type has the same
399−-- field names as the column AliasesOf of a `ColumnsType`.
400−type family SameFields
401− (datatypeInfo :: Type.DatatypeInfo) (columns :: RelationType)
402− :: Constraint where
403− SameFields
404− ('Type.ADT _module _datatype '[ 'Type.Record _constructor fields])
405− columns
406− = AllZip SameField fields columns
407− SameFields
408− ('Type.Newtype _module _datatype ('Type.Record _constructor fields))
409− columns
410− = AllZip SameField fields columns
464+type family RenameIfExists alias0 alias1 xs where
465+ RenameIfExists alias x '[] = '[]
466+ RenameIfExists alias0 alias1 ((alias0 ::: x0) ': xs) = (alias1 ::: x0) ': xs
467+ RenameIfExists alias0 alias1 (x ': xs) = x ': RenameIfExists alias0 alias1 xs
468+
469+-- | Check if a `TableConstraint` involves a column
470+type family ConstraintInvolves column constraint where
471+ ConstraintInvolves column ('Check columns) = column `Elem` columns
472+ ConstraintInvolves column ('Unique columns) = column `Elem` columns
473+ ConstraintInvolves column ('PrimaryKey columns) = column `Elem` columns
474+ ConstraintInvolves column ('ForeignKey columns tab refcolumns)
475+ = column `Elem` columns
476+
477+-- | Drop all `TableConstraint`s that involve a column
478+type family DropIfConstraintsInvolve column constraints where
479+ DropIfConstraintsInvolve column '[] = '[]
480+ DropIfConstraintsInvolve column (alias ::: constraint ': constraints)
481+ = If (ConstraintInvolves column constraint)
482+ (DropIfConstraintsInvolve column constraints)
483+ (alias ::: constraint ': DropIfConstraintsInvolve column constraints)
484+
485+-- | A `SchemumType` is a user-defined type, either a `Table`,
486+-- `View` or `Typedef`.
487+data SchemumType
488+ = Table TableType
489+ | View RowType
490+ | Typedef PGType
491+ | Index IndexType
492+ | Function FunctionType
493+ | Operator OperatorType
494+ | UnsafeSchemum Symbol
495+
496+type FunctionType = ([NullityType], ReturnsType)
497+
498+data IndexType
499+ = Btree
500+ | Hash
501+ | Gist
502+ | Spgist
503+ | Gin
504+ | Brin
505+
506+data ReturnsType
507+ = Returns NullityType
508+ | ReturnsTable RowType
509+
510+data OperatorType
511+ = BinaryOp NullityType NullityType NullityType
512+ | LeftOp NullityType NullityType
513+ | RightOp NullityType NullityType
514+
515+{- | The schema of a database consists of a list of aliased,
516+user-defined `SchemumType`s.
517+
518+>>> :{
519+type family Schema :: SchemaType where
520+ Schema =
521+ '[ "users" ::: 'Table (
522+ '[ "pk_users" ::: 'PrimaryKey '["id"] ] :=>
523+ '[ "id" ::: 'Def :=> 'NotNull 'PGint4
524+ , "name" ::: 'NoDef :=> 'NotNull 'PGtext
525+ ])
526+ , "emails" ::: 'Table (
527+ '[ "pk_emails" ::: 'PrimaryKey '["id"]
528+ , "fk_user_id" ::: 'ForeignKey '["user_id"] "users" '["id"]
529+ ] :=>
530+ '[ "id" ::: 'Def :=> 'NotNull 'PGint4
531+ , "user_id" ::: 'NoDef :=> 'NotNull 'PGint4
532+ , "email" ::: 'NoDef :=> 'Null 'PGtext
533+ ])
534+ ]
535+:}
536+-}
537+type SchemaType = [(Symbol,SchemumType)]
538+
539+{- |
540+A database contains one or more named schemas, which in turn contain tables.
541+The same object name can be used in different schemas without conflict;
542+for example, both schema1 and myschema can contain tables named mytable.
543+Unlike databases, schemas are not rigidly separated:
544+a user can access objects in any of the schemas in the database they are connected to,
545+if they have privileges to do so.
546+
547+There are several reasons why one might want to use schemas:
548+
549+ * To allow many users to use one database without interfering with each other.
550+ * To organize database objects into logical groups to make them more manageable.
551+ * Third-party applications can be put into separate schemas
552+ so they do not collide with the names of other objects.
553+-}
554+type SchemasType = [(Symbol,SchemaType)]
555+
556+-- | A type family to use for a single schema database.
557+type family Public (schema :: SchemaType) :: SchemasType
558+ where Public schema = '["public" ::: schema]
559+
560+-- | `IsPGlabel` looks very much like the `IsLabel` class. Whereas
561+-- the overloaded label, `fromLabel` is used for column references,
562+-- `label`s are used for enum terms. A `label` is called with
563+-- type application like `label @"beef"`.
564+class IsPGlabel (label :: Symbol) expr where label :: expr
565+instance label ~ label1
566+ => IsPGlabel label (PGlabel label1) where label = PGlabel
567+instance labels ~ '[label]
568+ => IsPGlabel label (NP PGlabel labels) where label = PGlabel :* Nil
569+-- | A `PGlabel` unit type with an `IsPGlabel` instance
570+data PGlabel (label :: Symbol) = PGlabel
571+instance KnownSymbol label => RenderSQL (PGlabel label) where
572+ renderSQL _ = "\'" <> renderSymbol @label <> "\'"
573+instance All KnownSymbol labels => RenderSQL (NP PGlabel labels) where
574+ renderSQL
575+ = commaSeparated
576+ . hcollapse
577+ . hcmap (Proxy @KnownSymbol) (K . renderSQL)
578+
579+-- | Is a type a valid JSON key?
580+type PGJsonKey = '[ 'PGint2, 'PGint4, 'PGtext ]
581+
582+-- | Is a type a valid JSON type?
583+type PGJsonType = '[ 'PGjson, 'PGjsonb ]
584+
585+-- | Utility class for `AllUnique` to provide nicer error messages.
586+class IsNotElem x isElem where
587+instance IsNotElem x 'False where
588+instance (TypeError ( 'Text "Cannot assign to "
589+ ':<>: 'ShowType alias
590+ ':<>: 'Text " more than once"))
591+ => IsNotElem '(alias, a) 'True where
592+
593+-- | No elem of @xs@ appears more than once, in the context of assignment.
594+class AllUnique (xs :: [(Symbol, a)]) where
595+instance AllUnique '[] where
596+instance (IsNotElem x (Elem x xs), AllUnique xs) => AllUnique (x ': xs) where
squeal-postgresql/src/Squeal/PostgreSQL/Transaction.hsnew file+252
@@ -0,0 +1,252 @@
1+{-|
2+Module: Squeal.PostgreSQL.Transaction
3+Description: Squeal transaction control language
4+Copyright: (c) Eitan Chatav, 2019
5+Maintainer: eitan@morphism.tech
6+Stability: experimental
7+
8+Squeal transaction control language.
9+-}
10+
11+{-# LANGUAGE
12+ DataKinds
13+ , FlexibleContexts
14+ , LambdaCase
15+ , OverloadedStrings
16+ , TypeInType
17+#-}
18+
19+module Squeal.PostgreSQL.Transaction
20+ ( -- * Transaction
21+ transactionally
22+ , transactionally_
23+ , transactionallyRetry
24+ , ephemerally
25+ , ephemerally_
26+ , begin
27+ , commit
28+ , rollback
29+ -- * Transaction Mode
30+ , TransactionMode (..)
31+ , defaultMode
32+ , longRunningMode
33+ , IsolationLevel (..)
34+ , AccessMode (..)
35+ , DeferrableMode (..)
36+ ) where
37+
38+import UnliftIO
39+
40+import Squeal.PostgreSQL.Manipulation
41+import Squeal.PostgreSQL.Render
42+import Squeal.PostgreSQL.PQ
43+
44+{- | Run a computation `transactionally`;
45+first `begin`,
46+then run the computation,
47+`onException` `rollback` and rethrow the exception,
48+otherwise `commit` and `return` the result.
49+-}
50+transactionally
51+ :: (MonadUnliftIO tx, MonadPQ schemas tx)
52+ => TransactionMode
53+ -> tx x -- ^ run inside a transaction
54+ -> tx x
55+transactionally mode tx = mask $ \restore -> do
56+ manipulate_ $ begin mode
57+ result <- restore tx `onException` (manipulate_ rollback)
58+ manipulate_ commit
59+ return result
60+
61+-- | Run a computation `transactionally_`, in `defaultMode`.
62+transactionally_
63+ :: (MonadUnliftIO tx, MonadPQ schemas tx)
64+ => tx x -- ^ run inside a transaction
65+ -> tx x
66+transactionally_ = transactionally defaultMode
67+
68+{- |
69+`transactionallyRetry` a computation;
70+
71+* first `begin`,
72+* then `try` the computation,
73+ - if it raises a serialization failure then `rollback` and restart the transaction,
74+ - if it raises any other exception then `rollback` and rethrow the exception,
75+ - otherwise `commit` and `return` the result.
76+-}
77+transactionallyRetry
78+ :: (MonadUnliftIO tx, MonadPQ schemas tx)
79+ => TransactionMode
80+ -> tx x -- ^ run inside a transaction
81+ -> tx x
82+transactionallyRetry mode tx = mask $ \restore ->
83+ loop . try $ do
84+ x <- restore tx
85+ manipulate_ commit
86+ return x
87+ where
88+ loop attempt = do
89+ manipulate_ $ begin mode
90+ attempt >>= \case
91+ Left (PQException (PQState _ (Just "40001") _)) -> do
92+ manipulate_ rollback
93+ loop attempt
94+ Left err -> do
95+ manipulate_ rollback
96+ throwIO err
97+ Right x -> return x
98+
99+{- | Run a computation `ephemerally`;
100+Like `transactionally` but always `rollback`, useful in testing.
101+-}
102+ephemerally
103+ :: (MonadUnliftIO tx, MonadPQ schemas tx)
104+ => TransactionMode
105+ -> tx x -- ^ run inside an ephemeral transaction
106+ -> tx x
107+ephemerally mode tx = mask $ \restore -> do
108+ manipulate_ $ begin mode
109+ result <- restore tx `onException` (manipulate_ rollback)
110+ manipulate_ rollback
111+ return result
112+
113+{- | Run a computation `ephemerally` in `defaultMode`. -}
114+ephemerally_
115+ :: (MonadUnliftIO tx, MonadPQ schemas tx)
116+ => tx x -- ^ run inside an ephemeral transaction
117+ -> tx x
118+ephemerally_ = ephemerally defaultMode
119+
120+-- | @BEGIN@ a transaction.
121+begin :: TransactionMode -> Manipulation_ schemas () ()
122+begin mode = UnsafeManipulation $ "BEGIN" <+> renderSQL mode
123+
124+-- | @COMMIT@ a transaction.
125+commit :: Manipulation_ schemas () ()
126+commit = UnsafeManipulation "COMMIT"
127+
128+-- | @ROLLBACK@ a transaction.
129+rollback :: Manipulation_ schemas () ()
130+rollback = UnsafeManipulation "ROLLBACK"
131+
132+-- | The available transaction characteristics are the transaction `IsolationLevel`,
133+-- the transaction `AccessMode` (`ReadWrite` or `ReadOnly`), and the `DeferrableMode`.
134+data TransactionMode = TransactionMode
135+ { isolationLevel :: IsolationLevel
136+ , accessMode :: AccessMode
137+ , deferrableMode :: DeferrableMode
138+ } deriving (Show, Eq)
139+
140+-- | `TransactionMode` with a `Serializable` `IsolationLevel`,
141+-- `ReadWrite` `AccessMode` and `NotDeferrable` `DeferrableMode`.
142+defaultMode :: TransactionMode
143+defaultMode = TransactionMode ReadCommitted ReadWrite NotDeferrable
144+
145+-- | `TransactionMode` with a `Serializable` `IsolationLevel`,
146+-- `ReadOnly` `AccessMode` and `Deferrable` `DeferrableMode`.
147+-- This mode is well suited for long-running reports or backups.
148+longRunningMode :: TransactionMode
149+longRunningMode = TransactionMode Serializable ReadOnly Deferrable
150+
151+-- | Render a `TransactionMode`.
152+instance RenderSQL TransactionMode where
153+ renderSQL mode =
154+ "ISOLATION LEVEL"
155+ <+> renderSQL (isolationLevel mode)
156+ <+> renderSQL (accessMode mode)
157+ <+> renderSQL (deferrableMode mode)
158+
159+-- | The SQL standard defines four levels of transaction isolation.
160+-- The most strict is `Serializable`, which is defined by the standard in a paragraph
161+-- which says that any concurrent execution of a set of `Serializable` transactions is
162+-- guaranteed to produce the same effect as running them one at a time in some order.
163+-- The other three levels are defined in terms of phenomena, resulting from interaction
164+-- between concurrent transactions, which must not occur at each level.
165+-- The phenomena which are prohibited at various levels are:
166+--
167+-- __Dirty read__: A transaction reads data written by a concurrent uncommitted transaction.
168+--
169+-- __Nonrepeatable read__: A transaction re-reads data it has previously read and finds that data
170+-- has been modified by another transaction (that committed since the initial read).
171+--
172+-- __Phantom read__: A transaction re-executes a query returning a set of rows that satisfy
173+-- a search condition and finds that the set of rows satisfying the condition
174+-- has changed due to another recently-committed transaction.
175+--
176+-- __Serialization anomaly__: The result of successfully committing a group of transactions is inconsistent
177+-- with all possible orderings of running those transactions one at a time.
178+--
179+-- In PostgreSQL, you can request any of the four standard transaction
180+-- isolation levels, but internally only three distinct isolation levels are implemented,
181+-- i.e. PostgreSQL's `ReadUncommitted` mode behaves like `ReadCommitted`.
182+-- This is because it is the only sensible way to map the standard isolation levels to
183+-- PostgreSQL's multiversion concurrency control architecture.
184+data IsolationLevel
185+ = Serializable
186+ -- ^ Dirty read is not possible.
187+ -- Nonrepeatable read is not possible.
188+ -- Phantom read is not possible.
189+ -- Serialization anomaly is not possible.
190+ | RepeatableRead
191+ -- ^ Dirty read is not possible.
192+ -- Nonrepeatable read is not possible.
193+ -- Phantom read is not possible.
194+ -- Serialization anomaly is possible.
195+ | ReadCommitted
196+ -- ^ Dirty read is not possible.
197+ -- Nonrepeatable read is possible.
198+ -- Phantom read is possible.
199+ -- Serialization anomaly is possible.
200+ | ReadUncommitted
201+ -- ^ Dirty read is not possible.
202+ -- Nonrepeatable read is possible.
203+ -- Phantom read is possible.
204+ -- Serialization anomaly is possible.
205+ deriving (Show, Eq)
206+
207+-- | Render an `IsolationLevel`.
208+instance RenderSQL IsolationLevel where
209+ renderSQL = \case
210+ Serializable -> "SERIALIZABLE"
211+ ReadCommitted -> "READ COMMITTED"
212+ ReadUncommitted -> "READ UNCOMMITTED"
213+ RepeatableRead -> "REPEATABLE READ"
214+
215+-- | The transaction access mode determines whether the transaction is `ReadWrite` or `ReadOnly`.
216+-- `ReadWrite` is the default. When a transaction is `ReadOnly`,
217+-- the following SQL commands are disallowed:
218+-- @INSERT@, @UPDATE@, @DELETE@, and @COPY FROM@
219+-- if the table they would write to is not a temporary table;
220+-- all @CREATE@, @ALTER@, and @DROP@ commands;
221+-- @COMMENT@, @GRANT@, @REVOKE@, @TRUNCATE@;
222+-- and @EXPLAIN ANALYZE@ and @EXECUTE@ if the command they would execute is among those listed.
223+-- This is a high-level notion of `ReadOnly` that does not prevent all writes to disk.
224+data AccessMode
225+ = ReadWrite
226+ | ReadOnly
227+ deriving (Show, Eq)
228+
229+-- | Render an `AccessMode`.
230+instance RenderSQL AccessMode where
231+ renderSQL = \case
232+ ReadWrite -> "READ WRITE"
233+ ReadOnly -> "READ ONLY"
234+
235+-- | The `Deferrable` transaction property has no effect
236+-- unless the transaction is also `Serializable` and `ReadOnly`.
237+-- When all three of these properties are selected for a transaction,
238+-- the transaction may block when first acquiring its snapshot,
239+-- after which it is able to run without the normal overhead of a
240+-- `Serializable` transaction and without any risk of contributing
241+-- to or being canceled by a serialization failure.
242+-- This `longRunningMode` is well suited for long-running reports or backups.
243+data DeferrableMode
244+ = Deferrable
245+ | NotDeferrable
246+ deriving (Show, Eq)
247+
248+-- | Render a `DeferrableMode`.
249+instance RenderSQL DeferrableMode where
250+ renderSQL = \case
251+ Deferrable -> "DEFERRABLE"
252+ NotDeferrable -> "NOT DEFERRABLE"
squeal-postgresql/test/Doc.hsnew file+6
@@ -0,0 +1,6 @@
1+module Main (main) where
2+
3+import Test.DocTest
4+
5+main :: IO ()
6+main = doctest [ "-isrc", "src" ]
squeal-postgresql/test/DocTest.hsdeleted−14
@@ -1,14 +0,0 @@
1−module Main (main) where
2−
3−import Test.DocTest
4−
5−main :: IO ()
6−main = doctest
7− [ "-isrc"
8− , "src/Squeal/PostgreSQL/Binary.hs"
9− , "src/Squeal/PostgreSQL/Definition.hs"
10− , "src/Squeal/PostgreSQL/Manipulation.hs"
11− , "src/Squeal/PostgreSQL/Query.hs"
12− , "src/Squeal/PostgreSQL/Expression.hs"
13− , "src/Squeal/PostgreSQL/PQ.hs"
14− ]
squeal-postgresql/test/Property.hsnew file+166
@@ -0,0 +1,166 @@
1+{-# LANGUAGE
2+ DataKinds
3+ , GADTs
4+ , LambdaCase
5+ , OverloadedLabels
6+ , OverloadedStrings
7+ , TypeApplications
8+ , TypeOperators
9+#-}
10+
11+module Main (main) where
12+
13+import Control.Monad.Trans
14+import Data.ByteString (ByteString)
15+import Data.ByteString.Char8 (unpack)
16+import Data.Scientific (fromFloatDigits)
17+import Data.Fixed (Fixed(MkFixed), Micro, Pico)
18+import Data.String (IsString(fromString))
19+import Data.Time
20+import Squeal.PostgreSQL hiding (check, defaultMain, Group)
21+import Hedgehog hiding (Range)
22+import qualified Hedgehog.Gen as Gen
23+import qualified Hedgehog.Main as Main
24+import qualified Hedgehog.Range as Range
25+
26+main :: IO ()
27+main = Main.defaultMain [checkSequential roundtrips]
28+
29+roundtrips :: Group
30+roundtrips = Group "roundtrips"
31+ [ roundtrip int2 genInt16
32+ , roundtrip int4 genInt32
33+ , roundtrip int8 genInt64
34+ , roundtrip bool Gen.bool
35+ , roundtrip numeric genScientific
36+ , roundtrip float4 genFloat
37+ , roundtrip float8 genDouble
38+ , roundtripOn normalizeTimeOfDay time genTimeOfDay
39+ -- , roundtrip timetz genTimeWithZone normalizeTimeWithZone
40+ , roundtripOn normalizeLocalTime timestamp genLocalTime
41+ , roundtrip timestamptz genUTCTime
42+ , roundtrip date genDay
43+ , roundtrip interval genDiffTime
44+ , roundtripOn normalizeIntRange int4range (genRange genInt32)
45+ , roundtripOn normalizeIntRange int8range (genRange genInt64)
46+ , roundtrip numrange (genRange genScientific)
47+ , roundtripOn (fmap normalizeLocalTime) tsrange (genRange genLocalTime)
48+ , roundtrip tstzrange (genRange genUTCTime)
49+ , roundtripOn normalizeIntRange daterange (genRange genDay)
50+ ]
51+ where
52+ genInt16 = Gen.int16 Range.exponentialBounded
53+ genInt32 = Gen.int32 Range.exponentialBounded
54+ genInt64 = Gen.int64 Range.exponentialBounded
55+ genScientific = fromFloatDigits <$> genFloat
56+ genPosFloat = Gen.float
57+ (Range.exponentialFloatFrom 1 minPosFloat maxPosFloat)
58+ genFloat = Gen.prune $ Gen.choice
59+ [ genPosFloat
60+ , negate <$> genPosFloat
61+ , Gen.element [0,1/0] ]
62+ genPosDouble = Gen.double
63+ (Range.exponentialFloatFrom 1 minPosFloat maxPosFloat)
64+ genDouble = Gen.prune $ Gen.choice
65+ [ genPosDouble
66+ , negate <$> genPosDouble
67+ , Gen.element [0,1/0] ]
68+ genRange gen = do
69+ lb <- gen
70+ ub <- Gen.filter (lb <) gen
71+ Gen.element
72+ [ Empty, singleton lb, whole
73+ , lb <=..<= ub , lb <=..< ub, lb <..<= ub, lb <..< ub
74+ , atLeast lb, moreThan lb, atMost ub, lessThan ub ]
75+ genDay = do
76+ y <- toInteger <$> Gen.int (Range.constant 2000 2019)
77+ m <- Gen.int (Range.constant 1 12)
78+ d <- Gen.int (Range.constant 1 28)
79+ return $ fromGregorian y m d
80+ genDiffTime = secondsToDiffTime . toInteger <$>
81+ Gen.int (Range.constant 0 86401)
82+ genUTCTime = UTCTime <$> genDay <*> genDiffTime
83+ genTimeOfDay = do
84+ h <- Gen.int (Range.constant 0 23)
85+ m <- Gen.int (Range.constant 0 59)
86+ s <- MkFixed . toInteger <$> Gen.int (Range.constant 0 59)
87+ return $ TimeOfDay h m s
88+ genLocalTime = LocalTime <$> genDay <*> genTimeOfDay
89+ -- genTimeZone = Gen.element $ map (read @TimeZone)
90+ -- [ "UTC", "UT", "GMT", "EST", "EDT", "CST"
91+ -- , "CDT", "MST", "MDT", "PST", "PDT" ]
92+ -- genTimeWithZone = (,) <$> genTimeOfDay <*> genTimeZone
93+
94+roundtrip
95+ :: (OidOf ty, ToParam x ty, FromValue ty x, Show x, Eq x)
96+ => TypeExpression schemas ('NotNull ty)
97+ -> Gen x
98+ -> (PropertyName, Property)
99+roundtrip = roundtripOn id
100+
101+roundtripOn
102+ :: (OidOf ty, ToParam x ty, FromValue ty x, Show x, Eq x)
103+ => (x -> x)
104+ -> TypeExpression schemas ('NotNull ty)
105+ -> Gen x
106+ -> (PropertyName, Property)
107+roundtripOn norm ty gen = propertyWithName $ do
108+ x <- forAll gen
109+ Just (Only y) <- lift . withConnection connectionString $
110+ firstRow =<< runQueryParams
111+ (values_ (parameter @1 ty `as` #fromOnly)) (Only x)
112+ norm x === y
113+ where
114+ propertyWithName prop =
115+ (fromString (unpack (renderSQL ty)), property prop)
116+
117+maxPosFloat :: RealFloat a => a
118+maxPosFloat = x
119+ where
120+ n = floatDigits x
121+ b = floatRadix x
122+ (_, u) = floatRange x
123+ x = encodeFloat (b^n - 1) (u - n)
124+
125+minPosFloat :: RealFloat a => a
126+minPosFloat = x
127+ where
128+ n = floatDigits x
129+ b = floatRadix x
130+ (l, _) = floatRange x
131+ x = encodeFloat (b^n - 1) (l - n - 1)
132+
133+connectionString :: ByteString
134+connectionString = "host=localhost port=5432 dbname=exampledb"
135+
136+normalizeIntRange :: (Enum int, Ord int) => Range int -> Range int
137+normalizeIntRange = \case
138+ Empty -> Empty
139+ NonEmpty l u ->
140+ let
141+ l' = normalizeL l
142+ u' = normalizeU u
143+ in if emptyNormalized l' u' then Empty else NonEmpty l' u'
144+ where
145+ normalizeL = \case
146+ Open l -> Closed (succ l)
147+ normalized -> normalized
148+ normalizeU = \case
149+ Closed u -> Open (succ u)
150+ normalized -> normalized
151+ emptyNormalized (Closed l) (Open u) = l >= u
152+ emptyNormalized _ _ = False
153+
154+normalizeTimeOfDay :: TimeOfDay -> TimeOfDay
155+normalizeTimeOfDay (TimeOfDay h m s) = TimeOfDay h m
156+ . fromRational @Pico
157+ . toRational @Micro
158+ . fromRational @Micro
159+ . toRational @Pico
160+ $ s
161+
162+normalizeLocalTime :: LocalTime -> LocalTime
163+normalizeLocalTime (LocalTime d t) = LocalTime d (normalizeTimeOfDay t)
164+
165+-- normalizeTimeWithZone :: (TimeOfDay, TimeZone) -> (TimeOfDay, TimeZone)
166+-- normalizeTimeWithZone (t, z) = (normalizeTimeOfDay t, z)
squeal-postgresql/test/Spec.hs+136−1
@@ -1 +1,136 @@
1−{-# OPTIONS_GHC -F -pgmF hspec-discover #-}
1+{-# LANGUAGE
2+ DataKinds
3+ , DeriveAnyClass
4+ , DeriveGeneric
5+ , DerivingStrategies
6+ , DuplicateRecordFields
7+ , FlexibleContexts
8+ , OverloadedLabels
9+ , OverloadedLists
10+ , OverloadedStrings
11+ , TypeApplications
12+ , TypeFamilies
13+ , TypeInType
14+ , TypeOperators
15+#-}
16+
17+module Main (main) where
18+
19+import Control.Concurrent.Async (replicateConcurrently)
20+import Data.ByteString (ByteString)
21+import Data.Int (Int32)
22+import Data.Text (Text)
23+import Test.Hspec
24+
25+import qualified Generics.SOP as SOP
26+import qualified GHC.Generics as GHC
27+
28+import Squeal.PostgreSQL
29+
30+main :: IO ()
31+main = hspec spec
32+
33+type Schemas = Public
34+ '[ "users" ::: 'Table (
35+ '[ "pk_users" ::: 'PrimaryKey '["id"]
36+ , "unique_names" ::: 'Unique '["name"]
37+ ] :=>
38+ '[ "id" ::: 'Def :=> 'NotNull 'PGint4
39+ , "name" ::: 'NoDef :=> 'NotNull 'PGtext ] ) ]
40+
41+data User = User
42+ { userName :: Text
43+ } deriving stock (Eq, Show, GHC.Generic)
44+ deriving anyclass (SOP.Generic, SOP.HasDatatypeInfo)
45+
46+insertUser :: Manipulation_ Schemas User ()
47+insertUser = insertInto_ #users
48+ (Values_ (Default `as` #id :* Set (param @1) `as` #name))
49+
50+setup :: Definition (Public '[]) Schemas
51+setup =
52+ createTable #users
53+ ( serial `as` #id :*
54+ notNullable text `as` #name )
55+ ( primaryKey #id `as` #pk_users :*
56+ unique #name `as` #unique_names )
57+
58+teardown :: Definition Schemas (Public '[])
59+teardown = dropTable #users
60+
61+silence :: MonadPQ schemas pq => pq ()
62+silence = manipulate_ $
63+ UnsafeManipulation "SET client_min_messages TO WARNING;"
64+
65+setupDB :: IO ()
66+setupDB = withConnection connectionString $
67+ silence & pqThen (define setup)
68+
69+dropDB :: IO ()
70+dropDB = withConnection connectionString $
71+ silence & pqThen (define teardown)
72+
73+connectionString :: ByteString
74+connectionString = "host=localhost port=5432 dbname=exampledb"
75+
76+spec :: Spec
77+spec = before_ setupDB . after_ dropDB $ do
78+
79+ describe "Exceptions" $ do
80+
81+ let
82+ testUser = User "TestUser"
83+ newUser = manipulateParams_ insertUser
84+ insertUserTwice = newUser testUser >> newUser testUser
85+ err23505 = PQException $ PQState FatalError (Just "23505")
86+ (Just "ERROR: duplicate key value violates unique constraint \"unique_names\"\nDETAIL: Key (name)=(TestUser) already exists.\n")
87+
88+ it "should be thrown for constraint violation" $
89+ withConnection connectionString insertUserTwice
90+ `shouldThrow` (== err23505)
91+
92+ it "should be rethrown for constraint violation in a transaction" $
93+ withConnection connectionString (transactionally_ insertUserTwice)
94+ `shouldThrow` (== err23505)
95+
96+ describe "Pools" $
97+
98+ it "should manage concurrent transactions" $ do
99+ pool <- createConnectionPool
100+ "host=localhost port=5432 dbname=exampledb" 1 0.5 10
101+ let
102+ query :: Query_ (Public '[]) () (Only Char)
103+ query = values_ (literal 'a' `as` #fromOnly)
104+ session = usingConnectionPool pool . transactionally_ $ do
105+ result <- runQuery query
106+ Just (Only chr) <- firstRow result
107+ return chr
108+ chrs <- replicateConcurrently 10 session
109+ chrs `shouldSatisfy` all (== 'a')
110+
111+ describe "Ranges" $
112+
113+ it "should correctly decode ranges" $ do
114+
115+ rangesOut <- withConnection connectionString $ do
116+ let
117+ query :: Query_ (Public '[]) () (Only (Range Int32))
118+ query = values
119+ ( range int4range (atLeast 3) `as` #fromOnly )
120+ [ range int4range (3 <=..< 5) `as` #fromOnly
121+ , range int4range Empty `as` #fromOnly
122+ , range int4range whole `as` #fromOnly ]
123+ getRows =<< runQuery query
124+ (fromOnly <$> rangesOut :: [Range Int32]) `shouldBe`
125+ [ atLeast 3, 3 <=..< 5, Empty, whole ]
126+
127+ describe "Parameters" $ do
128+
129+ it "should run queries that don't reference all their parameters" $ do
130+
131+ out <- withConnection connectionString $ do
132+ let
133+ query :: Query_ (Public '[]) (Char,Int32) (Only Int32)
134+ query = values_ (param @2 `as` #fromOnly)
135+ firstRow =<< runQueryParams query ('a', 3 :: Int32)
136+ (fromOnly <$> out :: Maybe Int32) `shouldBe` Just 3
squeal-postgresql/test/Squeal/PostgreSQL/DefinitionSpec.hsdeleted−124
@@ -1,124 +0,0 @@
1−{-# LANGUAGE
2− DataKinds
3− , MagicHash
4− , OverloadedLabels
5− , OverloadedStrings
6− , TypeApplications
7− , TypeOperators
8−#-}
9−
10−module Squeal.PostgreSQL.DefinitionSpec where
11−
12−import Control.Category ((>>>))
13−import Data.Function
14−import Generics.SOP hiding (from)
15−import Test.Hspec
16−
17−import Squeal.PostgreSQL
18−
19−spec :: Spec
20−spec = do
21− let
22− definition `definitionRenders` str =
23− renderDefinition definition `shouldBe` str
24− it "should render CREATE TABLE statements" $ do
25− createTable #table1
26− ((int4 & notNull) `As` #col1 :* (int4 & notNull) `As` #col2 :* Nil)
27− [primaryKey (Column #col1 :* Column #col2 :* Nil)]
28− `definitionRenders`
29− "CREATE TABLE table1\
30− \ (col1 int4 NOT NULL, col2 int4 NOT NULL,\
31− \ PRIMARY KEY (col1, col2));"
32− createTable #table2
33− ( serial `As` #col1 :*
34− text `As` #col2 :*
35− (int8 & notNull & default_ 8) `As` #col3 :* Nil )
36− [check (#col3 .> 0)]
37− `definitionRenders`
38− "CREATE TABLE table2\
39− \ (col1 serial,\
40− \ col2 text,\
41− \ col3 int8 NOT NULL DEFAULT 8,\
42− \ CHECK ((col3 > 0)));"
43− let
44− statement :: Definition '[]
45− '[ "users" :::
46− '[ "id" ::: 'Optional ('NotNull 'PGint4)
47− , "username" ::: 'Required ('NotNull 'PGtext)
48− ]
49− , "emails" :::
50− '[ "id" ::: 'Optional ('NotNull 'PGint4)
51− , "userid" ::: 'Required ('NotNull 'PGint4)
52− , "email" ::: 'Required ('NotNull 'PGtext)
53− ]
54− ]
55− statement =
56− createTable #users
57− (serial `As` #id :* (text & notNull) `As` #username :* Nil)
58− [primaryKey (Column #id :* Nil)]
59− >>>
60− createTable #emails
61− ( serial `As` #id :*
62− (integer & notNull) `As` #userid :*
63− (text & notNull) `As` #email :* Nil )
64− [ primaryKey (Column #id :* Nil)
65− , foreignKey (Column #userid :* Nil) #users (Column #id :* Nil)
66− OnDeleteCascade OnUpdateRestrict
67− , unique (Column #email :* Nil)
68− , check (#email ./= "")
69− ]
70− statement `definitionRenders`
71− "CREATE TABLE users\
72− \ (id serial, username text NOT NULL,\
73− \ PRIMARY KEY (id));\
74− \ \
75− \CREATE TABLE emails\
76− \ (id serial,\
77− \ userid integer NOT NULL,\
78− \ email text NOT NULL,\
79− \ PRIMARY KEY (id),\
80− \ FOREIGN KEY (userid) REFERENCES users (id)\
81− \ ON DELETE CASCADE ON UPDATE RESTRICT,\
82− \ UNIQUE (email),\
83− \ CHECK ((email <> E'')));"
84− it "should render DROP TABLE statements" $ do
85− let
86− statement :: Definition Tables '[]
87− statement = dropTable #table1
88− statement `definitionRenders` "DROP TABLE table1;"
89−
90−type Columns =
91− '[ "col1" ::: 'Required ('NotNull 'PGint4)
92− , "col2" ::: 'Required ('NotNull 'PGint4)
93− ]
94−type Tables = '[ "table1" ::: Columns ]
95−type SumAndCol1 =
96− '[ "sum" ::: 'Required ('NotNull 'PGint4)
97− , "col1" ::: 'Required ('NotNull 'PGint4)
98− ]
99−type StudentsColumns = '["name" ::: 'Required ('NotNull 'PGtext)]
100−type StudentsTable = '["students" ::: StudentsColumns]
101−type OrderColumns =
102− '[ "orderID" ::: 'Required ('NotNull 'PGint4)
103− , "orderVal" ::: 'Required ('NotNull 'PGtext)
104− , "customerID" ::: 'Required ('NotNull 'PGint4)
105− , "shipperID" ::: 'Required ('NotNull 'PGint4)
106− ]
107−type CustomerColumns =
108− '[ "customerID" ::: 'Required ('NotNull 'PGint4)
109− , "customerVal" ::: 'Required ('NotNull 'PGfloat4)
110− ]
111−type ShipperColumns =
112− '[ "shipperID" ::: 'Required ('NotNull 'PGint4)
113− , "shipperVal" ::: 'Required ('NotNull 'PGbool)
114− ]
115−type JoinTables =
116− '[ "orders" ::: OrderColumns
117− , "customers" ::: CustomerColumns
118− , "shippers" ::: ShipperColumns
119− ]
120−type ValueColumns =
121− '[ "orderVal" ::: 'Required ('NotNull 'PGtext)
122− , "customerVal" ::: 'Required ('NotNull 'PGfloat4)
123− , "shipperVal" ::: 'Required ('NotNull 'PGbool)
124− ]
squeal-postgresql/test/Squeal/PostgreSQL/ManipulationSpec.hsdeleted−128
@@ -1,128 +0,0 @@
1−{-# LANGUAGE
2− DataKinds
3− , MagicHash
4− , OverloadedLabels
5− , OverloadedStrings
6− , TypeApplications
7− , TypeOperators
8−#-}
9−
10−module Squeal.PostgreSQL.ManipulationSpec where
11−
12−import Generics.SOP hiding (from)
13−import Test.Hspec
14−
15−import Squeal.PostgreSQL
16−
17−spec :: Spec
18−spec = do
19− let
20− manipulation `manipulationRenders` str =
21− renderManipulation manipulation `shouldBe` str
22− it "correctly renders returning INSERTs" $ do
23− let
24− statement :: Manipulation Tables '[] SumAndCol1
25− statement =
26− insertInto #table1 (Values (2 `As` #col1 :* 4 `As` #col2 :* Nil) [])
27− OnConflictDoRaise
28− (Returning $ (#col1 + #col2) `As` #sum :* #col1 `As` #col1 :* Nil)
29− statement `manipulationRenders`
30− "INSERT INTO table1 (col1, col2) VALUES (2, 4)\
31− \ RETURNING (col1 + col2) AS sum, col1 AS col1;"
32− it "correctly renders simple UPDATEs" $ do
33− let
34− statement :: Manipulation Tables '[] '[]
35− statement =
36− update #table1 (Set 2 `As` #col1 :* Same `As` #col2 :* Nil)
37− (#col1 ./= #col2) (Returning Nil)
38− statement `manipulationRenders`
39− "UPDATE table1 SET col1 = 2\
40− \ WHERE (col1 <> col2);"
41− it "correctly renders returning UPDATEs" $ do
42− let
43− statement :: Manipulation Tables '[] SumAndCol1
44− statement =
45− update #table1 (Set 2 `As` #col1 :* Same `As` #col2 :* Nil)
46− (#col1 ./= #col2)
47− (Returning $ (#col1 + #col2) `As` #sum :* #col1 `As` #col1 :* Nil)
48− statement `manipulationRenders`
49− "UPDATE table1 SET col1 = 2\
50− \ WHERE (col1 <> col2)\
51− \ RETURNING (col1 + col2) AS sum, col1 AS col1;"
52− it "correctly renders upsert INSERTs" $ do
53− let
54− statement :: Manipulation Tables '[] '[]
55− statement =
56− insertInto #table1 (Values (2 `As` #col1 :* 4 `As` #col2 :* Nil) [])
57− (OnConflictDoUpdate
58− (Set 2 `As` #col1 :* Same `As` #col2 :* Nil) Nothing)
59− (Returning Nil)
60− statement `manipulationRenders`
61− "INSERT INTO table1 (col1, col2) VALUES (2, 4)\
62− \ ON CONFLICT DO UPDATE\
63− \ SET col1 = 2;"
64− it "correctly renders returning upsert INSERTs" $ do
65− let
66− statement :: Manipulation Tables '[] SumAndCol1
67− statement =
68− insertInto #table1 (Values (2 `As` #col1 :* 4 `As` #col2 :* Nil) [])
69− (OnConflictDoUpdate
70− (Set 2 `As` #col1 :* Same `As` #col2 :* Nil)
71− (Just (#col1 ./= #col2)))
72− (Returning $ (#col1 + #col2) `As` #sum :* #col1 `As` #col1 :* Nil)
73− statement `manipulationRenders`
74− "INSERT INTO table1 (col1, col2) VALUES (2, 4)\
75− \ ON CONFLICT DO UPDATE\
76− \ SET col1 = 2\
77− \ WHERE (col1 <> col2)\
78− \ RETURNING (col1 + col2) AS sum, col1 AS col1;"
79− it "correctly renders DELETEs" $ do
80− let
81− statement :: Manipulation Tables '[] '[]
82− statement = deleteFrom #table1 (#col1 .== #col2) (Returning Nil)
83− statement `manipulationRenders`
84− "DELETE FROM table1 WHERE (col1 = col2);"
85− it "should be safe against SQL injection in literal text" $ do
86− let
87− statement :: Manipulation StudentsTable '[] '[]
88− statement = insertInto #students
89− (Values ("Robert'); DROP TABLE students;" `As` #name :* Nil) [])
90− OnConflictDoRaise (Returning Nil)
91− statement `manipulationRenders`
92− "INSERT INTO students (name) VALUES (E'Robert''); DROP TABLE students;');"
93−
94−type Columns =
95− '[ "col1" ::: 'Required ('NotNull 'PGint4)
96− , "col2" ::: 'Required ('NotNull 'PGint4)
97− ]
98−type Tables = '[ "table1" ::: Columns ]
99−type SumAndCol1 =
100− '[ "sum" ::: 'Required ('NotNull 'PGint4)
101− , "col1" ::: 'Required ('NotNull 'PGint4)
102− ]
103−type StudentsColumns = '["name" ::: 'Required ('NotNull 'PGtext)]
104−type StudentsTable = '["students" ::: StudentsColumns]
105−type OrderColumns =
106− '[ "orderID" ::: 'Required ('NotNull 'PGint4)
107− , "orderVal" ::: 'Required ('NotNull 'PGtext)
108− , "customerID" ::: 'Required ('NotNull 'PGint4)
109− , "shipperID" ::: 'Required ('NotNull 'PGint4)
110− ]
111−type CustomerColumns =
112− '[ "customerID" ::: 'Required ('NotNull 'PGint4)
113− , "customerVal" ::: 'Required ('NotNull 'PGfloat4)
114− ]
115−type ShipperColumns =
116− '[ "shipperID" ::: 'Required ('NotNull 'PGint4)
117− , "shipperVal" ::: 'Required ('NotNull 'PGbool)
118− ]
119−type JoinTables =
120− '[ "orders" ::: OrderColumns
121− , "customers" ::: CustomerColumns
122− , "shippers" ::: ShipperColumns
123− ]
124−type ValueColumns =
125− '[ "orderVal" ::: 'Required ('NotNull 'PGtext)
126− , "customerVal" ::: 'Required ('NotNull 'PGfloat4)
127− , "shipperVal" ::: 'Required ('NotNull 'PGbool)
128− ]
squeal-postgresql/test/Squeal/PostgreSQL/QuerySpec.hsdeleted−181
@@ -1,181 +0,0 @@
1−{-# LANGUAGE
2− DataKinds
3− , MagicHash
4− , OverloadedLabels
5− , OverloadedStrings
6− , TypeApplications
7− , TypeOperators
8−#-}
9−
10−module Squeal.PostgreSQL.QuerySpec where
11−
12−import Data.Function
13−import Generics.SOP hiding (from)
14−import Test.Hspec
15−
16−import Squeal.PostgreSQL
17−
18−spec :: Spec
19−spec = do
20− let
21− qry `queryRenders` str =
22− renderManipulation (queryStatement qry) `shouldBe` str
23− it "correctly renders a simple SELECT query" $ do
24− let
25− statement :: Query Tables '[] SumAndCol1
26− statement =
27− select ((#col1 + #col2) `As` #sum :* #col1 `As` #col1 :* Nil)
28− (from (Table (#table1 `As` #table1)) & where_ (#col1 .> #col2))
29− statement `queryRenders`
30− "SELECT (col1 + col2) AS sum, col1 AS col1\
31− \ FROM table1 AS table1 WHERE (col1 > col2);"
32− it "combines WHEREs using AND" $ do
33− let
34− statement :: Query Tables '[] SumAndCol1
35− statement =
36− select ((#col1 + #col2) `As` #sum :* #col1 `As` #col1 :* Nil)
37− (from (Table (#table1 `As` #table1)) & where_ true & where_ false)
38− statement `queryRenders`
39− "SELECT (col1 + col2) AS sum, col1 AS col1\
40− \ FROM table1 AS table1 WHERE (TRUE AND FALSE);"
41− it "performs sub SELECTs" $ do
42− let
43− statement :: Query Tables '[] SumAndCol1
44− statement =
45− selectStar (from (Subquery
46− (select ((#col1 + #col2) `As` #sum :* #col1 `As` #col1 :* Nil)
47− (from (Table (#table1 `As` #table1))) `As` #sub)))
48− statement `queryRenders`
49− "SELECT * FROM\
50− \ (SELECT (col1 + col2) AS sum, col1 AS col1\
51− \ FROM table1 AS table1) AS sub;"
52− it "does LIMIT clauses" $ do
53− let
54− statement :: Query Tables '[] Columns
55− statement = selectStar (from (Table (#table1 `As` #table1)) & limit 1)
56− statement `queryRenders` "SELECT * FROM table1 AS table1 LIMIT 1;"
57− it "should use the minimum of given LIMITs" $ do
58− let
59− statement :: Query Tables '[] Columns
60− statement =
61− selectStar (from (Table (#table1 `As` #table1)) & limit 1 & limit 2)
62− statement `queryRenders` "SELECT * FROM table1 AS table1 LIMIT 1;"
63− it "should render parameters using $ signs" $ do
64− let
65− statement :: Query Tables '[ 'Required ('NotNull 'PGbool)] Columns
66− statement = selectStar
67− (from (Table (#table1 `As` #table1)) & where_ (param @1))
68− statement `queryRenders`
69− "SELECT * FROM table1 AS table1 WHERE ($1 :: bool);"
70− it "does OFFSET clauses" $ do
71− let
72− statement :: Query Tables '[] Columns
73− statement =
74− selectStar (from (Table (#table1 `As` #table1)) & offset 1)
75− statement `queryRenders` "SELECT * FROM table1 AS table1 OFFSET 1;"
76− it "should use the sum of given OFFSETs" $ do
77− let
78− statement :: Query Tables '[] Columns
79− statement = selectStar
80− (from (Table (#table1 `As` #table1)) & offset 1 & offset 2)
81− statement `queryRenders` "SELECT * FROM table1 AS table1 OFFSET 3;"
82− it "should render GROUP BY and HAVING clauses" $ do
83− let
84− statement :: Query Tables '[] SumAndCol1
85− statement =
86− select (sum_ #col2 `As` #sum :* #col1 `As` #col1 :* Nil)
87− ( from (Table (#table1 `As` #table1))
88− & group (By #col1 :* Nil)
89− & having (#col1 + sum_ #col2 .> 1) )
90− statement `queryRenders`
91− "SELECT sum(col2) AS sum, col1 AS col1\
92− \ FROM table1 AS table1\
93− \ GROUP BY col1\
94− \ HAVING ((col1 + sum(col2)) > 1);"
95− describe "JOINs" $ do
96− it "should render CROSS JOINs" $ do
97− let
98− statement :: Query JoinTables '[] ValueColumns
99− statement = select
100− ( #orders ! #orderVal `As` #orderVal :*
101− #customers ! #customerVal `As` #customerVal :*
102− #shippers ! #shipperVal `As` #shipperVal :* Nil )
103− ( from (Table (#orders `As` #orders)
104− & CrossJoin (Table (#customers `As` #customers))
105− & CrossJoin (Table (#shippers `As` #shippers))) )
106− statement `queryRenders`
107− "SELECT\
108− \ orders.orderVal AS orderVal,\
109− \ customers.customerVal AS customerVal,\
110− \ shippers.shipperVal AS shipperVal\
111− \ FROM orders AS orders\
112− \ CROSS JOIN customers AS customers\
113− \ CROSS JOIN shippers AS shippers;"
114− it "should render INNER JOINs" $ do
115− let
116− statement :: Query JoinTables '[] ValueColumns
117− statement = select
118− ( (#orders ! #orderVal) `As` #orderVal
119− :* (#customers ! #customerVal) `As` #customerVal
120− :* (#shippers ! #shipperVal) `As` #shipperVal :* Nil)
121− ( from (Table (#orders `As` #orders)
122− & InnerJoin (Table (#customers `As` #customers))
123− ((#orders ! #customerID) .== (#customers ! #customerID))
124− & InnerJoin (Table (#shippers `As` #shippers))
125− ((#orders ! #shipperID) .== (#shippers ! #shipperID))))
126− statement `queryRenders`
127− "SELECT\
128− \ orders.orderVal AS orderVal,\
129− \ customers.customerVal AS customerVal,\
130− \ shippers.shipperVal AS shipperVal\
131− \ FROM orders AS orders\
132− \ INNER JOIN customers AS customers\
133− \ ON (orders.customerID = customers.customerID)\
134− \ INNER JOIN shippers AS shippers\
135− \ ON (orders.shipperID = shippers.shipperID);"
136− it "should render self JOINs" $ do
137− let
138− statement :: Query JoinTables '[] OrderColumns
139− statement = selectDotStar #orders1
140− (from (Table (#orders `As` #orders1)
141− & CrossJoin (Table (#orders `As` #orders2))))
142− statement `queryRenders`
143− "SELECT orders1.*\
144− \ FROM orders AS orders1\
145− \ CROSS JOIN orders AS orders2;"
146−
147−type Columns =
148− '[ "col1" ::: 'Required ('NotNull 'PGint4)
149− , "col2" ::: 'Required ('NotNull 'PGint4)
150− ]
151−type Tables = '[ "table1" ::: Columns ]
152−type SumAndCol1 =
153− '[ "sum" ::: 'Required ('NotNull 'PGint4)
154− , "col1" ::: 'Required ('NotNull 'PGint4)
155− ]
156−type StudentsColumns = '["name" ::: 'Required ('NotNull 'PGtext)]
157−type StudentsTable = '["students" ::: StudentsColumns]
158−type OrderColumns =
159− '[ "orderID" ::: 'Required ('NotNull 'PGint4)
160− , "orderVal" ::: 'Required ('NotNull 'PGtext)
161− , "customerID" ::: 'Required ('NotNull 'PGint4)
162− , "shipperID" ::: 'Required ('NotNull 'PGint4)
163− ]
164−type CustomerColumns =
165− '[ "customerID" ::: 'Required ('NotNull 'PGint4)
166− , "customerVal" ::: 'Required ('NotNull 'PGfloat4)
167− ]
168−type ShipperColumns =
169− '[ "shipperID" ::: 'Required ('NotNull 'PGint4)
170− , "shipperVal" ::: 'Required ('NotNull 'PGbool)
171− ]
172−type JoinTables =
173− '[ "orders" ::: OrderColumns
174− , "customers" ::: CustomerColumns
175− , "shippers" ::: ShipperColumns
176− ]
177−type ValueColumns =
178− '[ "orderVal" ::: 'Required ('NotNull 'PGtext)
179− , "customerVal" ::: 'Required ('NotNull 'PGfloat4)
180− , "shipperVal" ::: 'Required ('NotNull 'PGbool)
181− ]
squeal-presentation-raveline.mdnew file+794
@@ -0,0 +1,794 @@
1+# Squeal
2+
3+_A bridge between SQL and Haskell_
4+
5+by [@Raveline](https://github.com/raveline)
6+
7+---
8+
9+# Rationale
10+
11+Using `postgresql-simple` you have a typical "Trial, error, despair" workflow:
12+
13+- Write query manually or semi-automatically
14+
15+- Write haskell code using the query
16+
17+- Pray that the query syntax is correct
18+
19+- Pray that it returns what you want
20+
21+- Realize the inefficiency of prayer when it comes to SQL
22+
23+- Iterate till it works
24+
25+---
26+
27+![Can't take this anymore](http://gif.eraveline.eu/static/img/0x16e.gif)
28+
29+---
30+
31+# Use your best friend: GHC
32+
33+Squeal provides several eDSL to make your SQL typesafe:
34+
35+- Type level eDSL to express schema;
36+
37+- Value level eDSL to manipulate schema (plus migration, yeehaw !);
38+
39+- Type level eDSL to express queries;
40+
41+- Value level eDSL to perform queries
42+
43+However, it's not an ORM. There's no caching, lazy loading - you retain control over your memory. Also, joins - and mostly aggregation after joins - have to be handled manually.
44+
45+---
46+
47+# Part I. Schema & migration
48+
49+---
50+
51+# The Schema
52+
53+- The schema will be used to validate _everything_: migration, queries, etc.
54+
55+- A schema is mostly a collection of tables.
56+
57+- In this presentation, we will create a very basic database modeling a parliament. We will store _members of parliament_ and _parliamentary groups_.
58+
59+- A simple Schema to represent a Parliament could be:
60+
61+```haskell
62+type Schema = '[ "mp" ::: 'Table MemberOfParliament
63+ , "groupp" ::: 'Table ParliamentGroup ]
64+```
65+
66+---
67+
68+> _note_ We need the `DataKinds` extension to be able to express heterogenous lists containing
69+> specific types like this one.
70+
71+> You can perfectly call your table "group" and not "groupp" even though it is a
72+> keyword in SQL - Squeal queries will be properly escaped.
73+
74+---
75+
76+# A small example
77+
78+```haskell
79+type ParliamentaryGroup =
80+ '[ "pk_groupp" ::: 'PrimaryKey '["groupp_id"]]
81+ :=>
82+ '[ "groupp_id" ::: 'NoDef :=> 'NotNull 'PGuuid
83+ , "name" ::: 'NoDef :=> 'NotNull 'PGtext
84+ ]
85+```
86+
87+- That's a whole simple table defined in one go.
88+
89+- `:::` lets us define a column or a constraint.
90+
91+- `:=>` associates the constraints to the column.
92+
93+- Let's split constraints and column to study the syntax a bit more.
94+
95+---
96+
97+> _note_ We are using `:::` and `:=>` to quickly express associations when writing
98+> our schema. We need the `TypeOperators` extension.]
99+
100+---
101+
102+![What does this means ?!](http://gif.eraveline.eu/static/img/0x27e.gif)
103+
104+---
105+
106+# Defining a table
107+
108+```haskell
109+type MemberOfParliament =
110+ '[ "pk_mp" ::: 'PrimaryKey '["mp_id"]
111+ , "fk_mp_groupp" ::: 'ForeignKey '["mp_group"] "groupp" '["groupp_id"]
112+ ] :=> MpCols
113+```
114+
115+- A table is a collection of constraints associated to a collection of columns.
116+
117+- We defined a table named "mp".
118+
119+- It has a constraint named "pk_mp", defining its primary key on column "mp_id".
120+
121+- It has a constraint named "fk_mp_groupp" defining a foreign key on column "mg_group", connected to the column "groupp_id" of table "groupp".
122+
123+- These constraints will be associated to the columns defined in `MpCols`.
124+
125+---
126+
127+# Defining columns
128+
129+```haskell
130+type MpCols =
131+ '[ "mp_id" ::: 'NoDef :=> 'NotNull 'PGuuid
132+ , "first_name" ::: 'NoDef :=> 'NotNull 'PGtext
133+ , "last_name" ::: 'NoDef :=> 'NotNull 'PGtext
134+ ]
135+```
136+
137+- A listing of column associate, for each element:
138+
139+ * a name;
140+
141+ * the mention of an eventual default value;
142+
143+ * the nullability;
144+
145+ * the type (obviously).
146+
147+---
148+
149+> _note_ GHC is already helping. If I named the "mp_id" column differently,
150+> GHC would yell because I promised a primary key constraint on a column named `mp_id`, so there must be one.]
151+
152+---
153+
154+# Implementating the schema
155+
156+- We will carry this schema type pretty much everywhere.
157+
158+- But before we play with this schema, we need to implement it.
159+
160+---
161+
162+```haskell
163+setup :: Definition '[] Schema
164+setup =
165+ createTable #groupp
166+ ( notNullable uuid `as` #groupp_id
167+ :* notNullable text `as` #name)
168+ ( primaryKey #groupp_id `as` #pk_groupp )
169+ >>> createTable #mp
170+ ( notNullable uuid `as` #mp_id
171+ :* notNullable text `as` #first_name
172+ :* notNullable text `as` #last_name
173+ :* notNullable text `as` #mp_group)
174+ ( primaryKey #mp_id `as` #pk_mp
175+ :* foreignKey #mp_group #groupp #groupp_id
176+ OnDeleteCascade OnUpdateCascade
177+ `as` #fk_mp_groupp)
178+```
179+
180+---
181+
182+# Damn, that's verbose
183+
184+- Yes. But you need verbosity to get type safety.
185+
186+- On the plus side, it's fairly straightforward.
187+
188+- You use `:*` to compose the element of the heterogenous list of columns.
189+
190+- You use `>>>` to compose table creation.
191+
192+> _note_ The compiler will catch any mistype between Schema and
193+> definition; wrong nullability, wrong type, wrong name, etc.
194+
195+---
196+
197+> _note_ You'll also need `OverloadedLabels`, for naming stuff.
198+> This is mostly to avoid having to write manual proxies all
199+> the time and for convenience.
200+
201+---
202+
203+# Setting up the schema
204+
205+- Squeal comes with a very good migration manager, handling _upgrades_ AND
206+_downgrades_.
207+
208+- A migration is a simple type:
209+
210+```haskell
211+Migration io schema0 schema1
212+```
213+
214+- The first parameter is a BaseMonad (typically, IO).
215+
216+- The second parameter is "the current schema of your DB".
217+
218+- The last one is "what you will migrate to".
219+
220+- The `Definition` type used to define upgrade and downgrade functions use the
221+ same logic (from one schema to the other).
222+
223+---
224+
225+# Defining our first migration
226+
227+- We have the setup bit, we need the teardown:
228+
229+```haskell
230+tearDown :: Definition Schema '[]
231+tearDown = dropTable #mp >>> dropTable #groupp
232+```
233+
234+> _note_ GHC will also detect the _proper_ order of what you typed in
235+> downgrade and upgrade should there be any conflict (with foreign keys).
236+
237+```haskell
238+initDB :: Migration IO '[] Schema
239+initDB =
240+ Migration { name = "Schema creation"
241+ , up = void $ define setup
242+ , down = void $ define tearDown }
243+```
244+
245+---
246+
247+# Simple migrator example
248+
249+```haskell
250+main :: IO ()
251+main = do
252+ printSQL setup
253+ void $ withConnection connectionString $
254+ migrateUp $ single initDB
255+```
256+
257+- We print the migration query; you can do this for all queries generated through Squeal.
258+
259+- We use `migrateUp` to perform the migration.
260+
261+- You can run several migration at the same time, to run only one use `single`.
262+
263+---
264+
265+![That was easy](http://gif.eraveline.eu/static/img/0x47f.gif)
266+
267+---
268+
269+# Part II. Insertions
270+
271+---
272+
273+# Manipulations & Queries
274+
275+Besides the specific case of migration, you will mostly perform:
276+
277+- `Manipulation` : inserting, updating and deleting data.
278+
279+- `Query` : fetching data.
280+
281+- Both types are parametric over the same things:
282+
283+ * A schema
284+
285+ * Input parameters
286+
287+ * Output
288+
289+- Simplified, they look like this:
290+
291+```haskell
292+Manipulation schema params columns
293+
294+Query schema params columns
295+```
296+
297+
298+---
299+
300+# Our Haskell model
301+
302+```haskell
303+type Parliament = [Group]
304+
305+data Group =
306+ Group { name :: Text
307+ , members :: [MemberOfParliament] }
308+
309+data MemberOfParliament =
310+ MemberOfParliament { firstName :: Text
311+ , lastName :: Text }
312+```
313+
314+> _note_ We didn't use anything from Squeal.
315+> The model can be entirely separated from the persistence layer.
316+
317+---
318+
319+# Inserting a Parliamentary Group
320+
321+- A group is very simple: it's a uuid and a name. Let's define our params:
322+
323+```haskell
324+type GroupInsertionParams = '[ 'NotNull 'PGuuid
325+ , 'NotNull 'PGtext ]
326+```
327+
328+- Params are not named, but they are indexed. You just need nullability and type.
329+
330+---
331+
332+```haskell
333+groupInsertion :: Manipulation Schema GroupInsertionParams '[]
334+groupInsertion =
335+ insertRow_ #groupp ( Set (param @1) `as` #groupp_id
336+ :* Set (param @2) `as` #name )
337+```
338+
339+---
340+
341+- `TypeApplication` lets us use the index of parameters (counting from 1).
342+
343+- Once again: all this is checked by the compiler. Wrong name, wrong type... you'll get a compile error.
344+
345+- `insertRow_` is a simplified version of `insertRow`. `insertRow` lets you express a `RETURNING` clause and the expected behaviour in case of conflict.
346+
347+---
348+
349+_Inserting a Member of Parliament_
350+# Doing an INSERT INTO ... SELECT
351+
352+- We could create a naive query that takes MP uuid, first name, last name and group uuid...
353+
354+---
355+
356+- But that's boring. So let's use the `INSERT INTO ... SELECT`.
357+
358+---
359+
360+- We will build a query that will return as constants our MP's uuid, first name and last name...
361+
362+---
363+
364+- ... and fetch the uuid of a group given the name of the group.
365+
366+---
367+
368+- There's a `insertQuery` utility function for that. All we have to do is write the `select` !
369+
370+```haskell
371+mpInsertion :: Manipulation Schema MpParams '[]
372+mpInsertion =
373+ insertQuery_ #mp selectGroup -- we just have to write selectGroup !
374+```
375+
376+---
377+
378+_Inserting a Member of Parliament_
379+# The query type
380+
381+- A query looks just like a `Manipulation`:
382+
383+```haskell
384+Query schema params returns
385+```
386+
387+- Returns use a special syntax, that demands names, nullability and types:
388+
389+```haskell
390+type ExampleReturnType = '[ "some_column" ::: 'NotNull 'PGuuid
391+ , "other_column" ::: 'Null 'PGtext ]
392+```
393+
394+- It is not the same as the column definition we used in the schema. That one also expects that you specify, for each column, an eventual default:
395+
396+```haskell
397+type ExampleSchemaCols =
398+ '[ "some_column" ::: 'NoDef :=> 'NotNull 'PGuuid
399+ , "other_column" ::: 'NoDef :=> 'Null 'PGtext ]
400+```
401+
402+---
403+
404+_Inserting a Member of Parliament_
405+# Don't rewrite column definitions
406+
407+- We want our return type to be "all columns from table MP expressed as return type".
408+
409+- But we cannot reuse our neat `MpCols` alias, since the type do not match as we've just seen.
410+
411+- Hopefully, there's a neat Type Family that will let you convert any table you defined to the type of the equivalent row: `TableToRow`.
412+
413+- We finally have the signature for our SELECT query.
414+
415+```haskell
416+selectGroup :: Query Schema MpParams (TableToRow MemberOfParliament)
417+```
418+
419+---
420+
421+_Inserting a Member of Parliament_
422+# Our final Select query
423+
424+- Our intermediate query looks like this:
425+
426+```haskell
427+selectGroup =
428+ select
429+ ( param @1 `as` #mp_id
430+ :* param @2 `as` #first_name
431+ :* param @3 `as` #last_name
432+ :* #groupp ! #groupp_id `as` #mp_group
433+ )
434+ ( from (table #groupp)
435+ & where_ ( #groupp ! #name .== param @4 )
436+ )
437+```
438+
439+- The first three columns are constant defined through our params;
440+
441+- ... we alias the column name using `as`...
442+
443+- ... and when we need the result from the table we use the `#table ! #column` syntax.
444+
445+- We'll go back to the "from" block later.
446+
447+---
448+
449+# Dealing with the connection context
450+
451+- Queries are runned in a connection context:
452+
453+ * When dealing with a single-connection context, use the type `PQ`.
454+
455+ * When dealing with a pool of connection, use the type `PoolPQ`.
456+
457+- Or get rid of the context and use `mtl` style, with the typeclass `MonadPQ`.
458+
459+- We'll use that to demonstrate how to actually run our queries.
460+
461+---
462+
463+# Inserting a whole group
464+
465+```haskell
466+insertGroup :: (MonadPQ Schema m, MonadBaseControl IO m) => Group -> m ()
467+insertGroup g@(Group name _) = do
468+ uuid' <- liftBase nextRandom
469+ void $ manipulateParams groupInsertion (uuid', name)
470+ insertMps g
471+```
472+
473+- Remember that we defined a group as a name and a list of MPs.
474+
475+- We are in `MonadBaseControl`, so we cannot use `liftIO`, we need `liftBase`.
476+
477+- To perform a simple insertion, use `manipulateParams`. It takes into parameter
478+instances of `ToParam`, but you will typically use tuples or Generic-SOP.
479+
480+---
481+
482+# Inserting a bunch of MPs
483+
484+```haskell
485+insertMps :: (MonadPQ Schema m, MonadBaseControl IO m) => Group -> m ()
486+insertMps (Group groupName mps) =
487+ let tuplify Mp{..} = (, firstName, lastName, groupName) <$> nextRandom
488+ params = traverse tuplify mps
489+ in void $ liftBase params >>= traversePrepared mpInsertion
490+```
491+
492+- This time, we want to do a `preparedStatement`. We'll use `traversePrepare`
493+which behaves like `manipulateParams`, but expect a list of `ToParam`
494+instances.
495+
496+- We build our tuple manually again, mostly because we want to generate UUID on
497+the fly and we don't want to have them in our model.
498+
499+---
500+
501+# Inserting a whole parliament
502+
503+```haskell
504+insertParliament ::
505+ (MonadPQ Schema m, MonadBaseControl IO m) => Parliament -> m ()
506+insertParliament = traverse_ insertGroup
507+```
508+
509+- That's simple enough !
510+
511+- If we want to be a bit safer, though, we can wrap this call in a
512+`transactionally_` function, which will put all that in a transaction.
513+
514+---
515+
516+![Very simple](https://media1.tenor.com/images/0188c63209aced59f1583e1ca94e509e/tenor.gif?itemid=3550689)
517+
518+
519+---
520+
521+# Part III. Selects
522+
523+---
524+
525+# Composable queries
526+
527+- Building basic queries is easy, and is well documented.
528+
529+- However, the real interest of a tool like Squeal is in DRYness, and the documentation is still lacking in "how-to" related to composability.
530+
531+- I'll build an example showing how column selections and from clause can be factorized.
532+
533+- We want to write two queries:
534+
535+ * One to get all members of a specific group.
536+
537+ * One to get all the parliament.
538+
539+---
540+
541+# Decomposing a `Query`
542+
543+- A query typically stars with `select` (variants are available).
544+
545+- It then takes:
546+
547+ * A heterogenous list of fields with a scary signature;
548+
549+ * A virtual table (the from clause and filter clauses), called a `TableExpression`.
550+
551+- And return fields. Ours will look like this:
552+
553+```haskell
554+type GroupRowResult =
555+ '[ "groupName" ::: 'NotNull 'PGtext
556+ , "firstName" ::: 'NotNull 'PGtext
557+ , "lastName" ::: 'NotNull 'PGtext ]
558+```
559+
560+---
561+
562+# The Table Expression
563+
564+- It necessarily contains a `fromClause` (table, view or subquery, plus optional joins).
565+
566+- You can add where, groups, "HAVING" clause, order, etc.
567+
568+- `from` creates a basic `TableExpression` that you extend through various function to add clauses.
569+
570+- For our queries, we will share a common `FromClause`.
571+
572+---
573+
574+# The From Clause
575+
576+```
577+FromClause schema params from
578+```
579+
580+- We need Schema, input parameters and a `FromType` giving the available fields of the expression.
581+
582+- In our case, we'll join the table `mp` and the table `groupp`, meaning the `from` will be all fields of these tables.
583+
584+- We can use `TableToRow` to be more DRY:
585+
586+```haskell
587+type BaseParliamentSelection =
588+ '[ "g" ::: TableToRow GroupCols
589+ , "m" ::: TableToRow MpCols ]
590+```
591+
592+> _note_ We've also put everything with table aliases: "g" and "m".
593+
594+---
595+
596+# Writing our from clause
597+
598+```haskell
599+baseParliamentTables ::
600+ FromClause Schema (param :: [NullityType]) BaseParliamentSelection
601+baseParliamentTables =
602+ table
603+ (#groupp `as` #g)
604+ & innerJoin
605+ (table (#mp `as` #m))
606+ (#m ! #mp_group .== #g ! #groupp_id)
607+```
608+
609+- When picking "from" something, you need to specify the type with a function: `table` for a table, `view` for a view, etc.
610+
611+- All joins are available. `innerJoin` is the most basic one. It takes the joined table and the joining condition.
612+
613+- We have to specifiy the type of `param` (current limitation of the lib), even though _any_ params will be compatible with this, so we can plug `where` clauses depending on params should we need to !
614+
615+---
616+
617+# Typing the common selection
618+
619+- Both our querie will need the same fields. This has to be factorized too.
620+
621+- The scary signature of selection fields:
622+
623+```haskell
624+NP (Aliased (Expression schema from grouping params)) cols
625+```
626+
627+- `NP` is for heterogenous lists ("n-ary product").
628+
629+- `from` is the virtual table type, so our `BaseParliamentSelection`.
630+
631+- `grouping` is there to make a distinction between aggregated / unaggregated queries.
632+
633+- And finally, cols is the return type.
634+
635+---
636+
637+# Our common selection
638+
639+```haskell
640+groupSelection ::
641+ NP (Aliased (Expression Schema BaseParliamentSelection 'Ungrouped param))
642+ GroupRowResult
643+groupSelection =
644+ #g ! #name `as` #groupName
645+ :* #m ! #first_name `as` #firstName
646+ :* #m ! #last_name `as` #lastName
647+```
648+
649+- I hope you like big signatures.
650+
651+- But it's what let GHC checks that all alias and columns are available.
652+
653+- And that you're returning what you really intend to return.
654+
655+---
656+
657+# Putting it all together
658+
659+```haskell
660+selectParliament :: Query Schema '[] GroupRowResult
661+selectParliament =
662+ select groupSelection (from baseParliamentTables)
663+```
664+
665+```haskell
666+selectGroupMembers :: Query Schema '[ 'NotNull 'PGtext] GroupRowResult
667+selectGroupMembers =
668+ select groupSelection
669+ (from baseParliamentTables
670+ & where_ (#g ! #name .== param @1))
671+```
672+
673+- That is fairly DRY. And _entirely typesafe_.
674+
675+---
676+
677+# Actually fetching the data
678+
679+- We'll build an intermediary datatype representing our rows.
680+
681+- We'll make it match our row.
682+
683+- And we'll add generic-SOP so that we can build them from query results.
684+
685+```haskell
686+type GroupRowResult =
687+ '[ "groupName" ::: 'NotNull 'PGtext
688+ , "firstName" ::: 'NotNull 'PGtext
689+ , "lastName" ::: 'NotNull 'PGtext ]
690+```
691+
692+```haskell
693+data GroupRow =
694+ GroupRow { groupName :: Text
695+ , firstName :: Text
696+ , lastName :: Text }
697+ deriving (Generic)
698+
699+instance SOP.Generic GroupRow
700+instance SOP.HasDatatypeInfo GroupRow
701+```
702+
703+---
704+
705+# Aggregate result logic
706+
707+- We will get tabular, SQL data.
708+
709+- Our results will be `[GroupRow]`.
710+
711+- We'll build `Groups` from this:
712+
713+```haskell
714+buildGroup :: NE.NonEmpty GroupRow -> Group
715+buildGroup grs =
716+ let buildMP (GroupRow _ f l) = Mp f l
717+ name = groupName . NE.head $ grs
718+ members = NE.toList (buildMP <$> grs)
719+ in Group{..}
720+
721+rowToGroups :: [GroupRow] -> [Group]
722+rowToGroups =
723+ let grouped = fmap NE.fromList . L.groupBy ((==) `on` groupName)
724+ in fmap buildGroup . grouped
725+```
726+
727+---
728+
729+# Finally calling our queries
730+
731+- Query with params will use `runQueryParams`.
732+
733+- Query without params will use `runQuery`.
734+
735+- Result is inside a `MonadPQ` and of type `K` from generic-sop.
736+
737+- You get your actual result using `getRows`. Exemple:
738+
739+```haskell
740+getParliament :: (MonadPQ Schema m, MonadBaseControl IO m) => m [Group]
741+getParliament = do
742+ res <- runQuery selectParliament
743+ rows <- getRows res
744+ pure $ rowToGroups rows
745+```
746+
747+- In real life of course you'll write:
748+
749+```haskell
750+getParliament =
751+ rowToGroups <$> (runQuery selectParliament >>= getRows)
752+```
753+
754+---
755+
756+# Our query with params
757+
758+```haskell
759+getGroupMembers ::
760+ (MonadPQ Schema m, MonadBaseControl IO m) => Text -> m (Maybe Group)
761+getGroupMembers =
762+ listToMaybe . rowToGroups <$>
763+ (runQueryParams selectGroupMembers (Only t) >>= getRows)
764+```
765+
766+- And that's it.
767+
768+---
769+
770+![Eazy](https://media.tenor.com/images/8fc7c4077efe11b4a3a3b9ae4e643e87/tenor.gif)
771+
772+---
773+
774+# Conclusion
775+
776+---
777+
778+# Pros & Cons
779+
780+- Not everything is included: some cool stuff like array_agg and window functions are not available yet.
781+
782+- But development is _very_ active. `IN` clauses were missing but were added in the 4.0 released recently.
783+
784+- It's bleeding edge. You need latest LTS to be comfortable and psql >= 9.5.
785+
786+- It's Postgres-only but I would say that's a feature. Multi-DB tools are even more complex.
787+
788+- The author & maintainer is <3.
789+
790+- Typesafe. 'nuff said.
791+
792+---
793+
794+# Thank you !
squeal-presentation.pdf

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stack.yaml+6−1
@@ -1,3 +1,8 @@
1−resolver: nightly-2017-08-25
1+resolver: nightly-2019-07-14
22packages:
33- squeal-postgresql
4+
5+extra-deps:
6+- unliftio-pool-0.2.1.0
7+- github: morphismtech/free-categories
8+ commit: c0e555fbefb5c21619e532264c4dfeac556d0630