b6520e9 · squeal · git.iko.soy

squeal-postgresql/exe/Example.hs+23−11

compare with dev

unifiedsplit

@@ -1,15 +1,17 @@

1{-# LANGUAGE

2 DataKinds

3 , DeriveGeneric

4+ , FlexibleContexts

4 , OverloadedLabels

5 , OverloadedLabels

5 , OverloadedStrings

6 , OverloadedStrings

6 , TypeApplications

7 , TypeApplications

7 , TypeOperators

8 , TypeOperators

8#-}

9#-}

9

10

10−module Main (main) where

11+module Main (main, main2) where

11

12

12−import Control.Monad.Base (liftBase)

13+import Control.Monad (void)

14+import Control.Monad.Base (liftBase, MonadBase)

13import Data.Int (Int32)

15import Data.Int (Int32)

14import Data.Monoid ((<>))

16import Data.Monoid ((<>))

15import Data.Text (Text)

17import Data.Text (Text)

@@ -86,6 +88,17 @@ users =

86 , User "Carole" (Just "carole@hotmail.com")

88 , User "Carole" (Just "carole@hotmail.com")

87 ]

89 ]

88

90

91+session :: (MonadBase IO pq, MonadPQ Schema pq) => pq ()

92+session = do

93+ liftBase $ Char8.putStrLn "manipulating"

94+ idResults <- traversePrepared insertUser (Only . userName <$> users)

95+ ids <- traverse (fmap fromOnly . getRow (RowNumber 0)) idResults

96+ traversePrepared_ insertEmail (zip (ids :: [Int32]) (userEmail <$> users))

97+ liftBase $ Char8.putStrLn "querying"

98+ usersResult <- runQuery getUsers

99+ usersRows <- getRows usersResult

100+ liftBase $ print (usersRows :: [User])

101+

89main :: IO ()

102main :: IO ()

90main = do

103main = do

91 Char8.putStrLn "squeal"

104 Char8.putStrLn "squeal"

@@ -95,15 +108,14 @@ main = do

95 connection0 <- connectdb connectionString

108 connection0 <- connectdb connectionString

96 Char8.putStrLn "setting up schema"

109 Char8.putStrLn "setting up schema"

97 connection1 <- execPQ (define setup) connection0

110 connection1 <- execPQ (define setup) connection0

98− connection2 <- flip execPQ connection1 $ do

111+ connection2 <- execPQ session connection1

99− liftBase $ Char8.putStrLn "manipulating"

100− idResults <- traversePrepared insertUser (Only . userName <$> users)

101− ids <- traverse (fmap fromOnly . getRow (RowNumber 0)) idResults

102− traversePrepared_ insertEmail (zip (ids :: [Int32]) (userEmail <$> users))

103− liftBase $ Char8.putStrLn "querying"

104− usersResult <- runQuery getUsers

105− usersRows <- getRows usersResult

106− liftBase $ print (usersRows :: [User])

107 Char8.putStrLn "tearing down schema"

112 Char8.putStrLn "tearing down schema"

108 connection3 <- execPQ (define teardown) connection2

113 connection3 <- execPQ (define teardown) connection2

109 finish connection3

114 finish connection3

115+

116+main2 :: IO ()

117+main2 = void $

118+ withConnection "host=localhost port=5432 dbname=exampledb" . runPQ $

119+ define setup

120+ & pqThen session

121+ & thenDefine teardown

squeal-postgresql/squeal-postgresql.cabal+1−1

@@ -1,5 +1,5 @@

1name: squeal-postgresql

2−version: 0.1.0.0

2+version: 0.1.1.0

3synopsis: Squeal PostgreSQL Library

4description: Squeal is a type-safe embedding of PostgreSQL in Haskell

5homepage: https://github.com/morphismtech/squeal

squeal-postgresql/src/Squeal/PostgreSQL.hs+17−15

@@ -147,23 +147,25 @@

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. Since the

150+-- data and prints it out and finally closes the connection. We can thread

151−-- `Connection` tracks the schema of the database, we get a new one

151+-- the changing schema information through by using the indexed `PQ` monad

152−-- when we execute our statements.

152+-- transformer and when the schema doesn't change we can use `Monad` and

153+-- `MonadPQ` functionality.

153--

154--

154-- > main :: IO ()

155-- > main :: IO ()

155−-- > main = do

156+-- > main = void $

156−-- > connection0 <- connectdb "host=localhost port=5432 dbname=exampledb"

157+-- > withConnection "host=localhost port=5432 dbname=exampledb" . runPQ $

157−-- > connection1 <- execPQ (define setup) connection0

158+-- > define setup

158−-- > connection2 <- flip execPQ connection1 $ do

159+-- > & pqThen session

160+-- > & thenDefine teardown

161+-- > where

162+-- > session = do

159−-- > idResults <- traversePrepared insertUser (Only . userName <$> users)

163+-- > idResults <- traversePrepared insertUser (Only . userName <$> users)

160−-- > ids <- traverse (fmap fromOnly . getRow (RowNumber 0)) idResults

164+-- > ids <- traverse (fmap fromOnly . getRow (RowNumber 0)) idResults

161−-- > traversePrepared_ insertEmail (zip (ids :: [Int32]) (userEmail <$> users))

165+-- > traversePrepared_ insertEmail (zip (ids :: [Int32]) (userEmail <$> users))

162−-- > usersResult <- runQuery getUsers

166+-- > usersResult <- runQuery getUsers

163−-- > usersRows <- getRows usersResult

167+-- > usersRows <- getRows usersResult

164−-- > liftBase $ print (usersRows :: [User])

168+-- > liftBase $ print (usersRows :: [User])

165−-- > connection3 <- execPQ (define teardown) connection2

166−-- > finish connection3

167

169

168module Squeal.PostgreSQL

170module Squeal.PostgreSQL

169 ( module Squeal.PostgreSQL.Binary

171 ( module Squeal.PostgreSQL.Binary

squeal-postgresql/src/Squeal/PostgreSQL/Definition.hs+1−1

@@ -569,5 +569,5 @@ dropNotNull = UnsafeAlterColumn $ "DROP NOT NULL"

569-- in renderDefinition definition

570-- :}

571-- "ALTER TABLE tab ALTER COLUMN col TYPE numeric NOT NULL;"

572−alterType :: TypeExpression ty -> AlterColumn ty0 ty1

572+alterType :: TypeExpression ty -> AlterColumn ty0 ty

573alterType ty = UnsafeAlterColumn $ "TYPE" <+> renderTypeExpression ty

squeal-postgresql/src/Squeal/PostgreSQL/PQ.hs+5−4

@@ -141,13 +141,14 @@ finish = liftBase . LibPQ.finish . unConnection

141

142-- | Do `connectdb` and `finish` before and after a computation.

143withConnection

144− :: forall schema io x

144+ :: forall schema0 schema1 io x

145 . MonadBaseControl IO io

146 => ByteString

147− -> (Connection schema -> io x)

147+ -> (Connection schema0 -> io (x, Connection schema1))

148 -> io x

149+withConnection connString action = do

149−withConnection connString = bracket (connectdb connString) finish

150+ (x, _conn) <- bracket (connectdb connString) finish action

150−

151+ return x

151

152

152-- | We keep track of the schema via an Atkey indexed state monad transformer,

153-- | We keep track of the schema via an Atkey indexed state monad transformer,

153-- `PQ`.

154-- `PQ`.