@@ -1,18 +1,14 @@
1−{-# LANGUAGE DeriveDataTypeable #-}
1+{-# LANGUAGE DeriveDataTypeable, RecordWildCards, NamedFieldPuns #-}
2−{-# LANGUAGE NamedFieldPuns #-}
3−{-# LANGUAGE OverloadedStrings #-}
4−{-# LANGUAGE PatternGuards #-}
5−{-# LANGUAGE RecordWildCards #-}
6−{-# LANGUAGE ViewPatterns #-}
8------------------------------------------------------------------------------
3------------------------------------------------------------------------------
10-- Module: Database.PostgreSQL.Simple
5-- Module: Database.PostgreSQL.Simple
11-- Copyright: (c) 2011 MailRank, Inc.
6-- Copyright: (c) 2011 MailRank, Inc.
12−-- (c) 2011-2012 Leon P Smith
7+-- (c) 2011 Leon P Smith
13-- License: BSD3
8-- License: BSD3
14-- Maintainer: Leon P Smith <leon@melding-monads.com>
9-- Maintainer: Leon P Smith <leon@melding-monads.com>
15-- Stability: experimental
10-- Stability: experimental
11+-- Portability: portable
17-- A mid-level client library for the PostgreSQL database, aimed at ease of
13-- A mid-level client library for the PostgreSQL database, aimed at ease of
18-- use and high performance.
14-- use and high performance.
@@ -42,9 +38,6 @@ module Database.PostgreSQL.Simple
42 -- ** Modifying multiple rows at once
38 -- ** Modifying multiple rows at once
45− -- ** @RETURNING@: modifications that return results
48 -- * Extracting results
41 -- * Extracting results
49 -- $result
42 -- $result
@@ -55,35 +48,26 @@ module Database.PostgreSQL.Simple
57 -- * Types
50 -- * Types
58− Connection
52+ , Connection
63 , Binary(..)
55 , Binary(..)
64 , Only(..)
56 , Only(..)
66 -- ** Exceptions
57 -- ** Exceptions
67− , SomePostgreSqlException(..)
68 , SqlError(..)
58 , SqlError(..)
70− , FormatError(..)
59+ , FormatError(fmtMessage, fmtQuery, fmtParams)
71− , QueryError(..)
60+ , QueryError(qeMessage, qeQuery)
72− , ResultError(..)
61+ , ResultError(errSQLType, errHaskellType, errMessage)
73 -- * Connection management
62 -- * Connection management
74− , Base.connectPostgreSQL
76 , Base.connect
63 , Base.connect
77− , Base.withConnect
64+ , Base.connectPostgreSQL
78− , Base.ConnectInfo(..)
79− , Base.defaultConnectInfo
80 , Base.postgreSQLConnectionString
65 , Base.postgreSQLConnectionString
66+ , Base.defaultConnectInfo
81 -- * Queries that return results
68 -- * Queries that return results
84− -- ** Queries taking parser as argument
87 -- * Queries that stream results
71 -- * Queries that stream results
88 , FoldOptions(..)
72 , FoldOptions(..)
89 , FetchQuantity(..)
73 , FetchQuantity(..)
@@ -94,15 +78,6 @@ module Database.PostgreSQL.Simple
94 , foldWithOptions_
78 , foldWithOptions_
96 , forEach_
80 , forEach_
98− -- ** Queries that stream results taking a parser as an argument
100− , foldWithOptionsAndParser
102− , foldWithOptionsAndParser_
106 -- * Statements that do not return results
81 -- * Statements that do not return results
107 , execute
82 , execute
108 , execute_
83 , execute_
@@ -110,9 +85,18 @@ module Database.PostgreSQL.Simple
110-- , Base.insertID
85-- , Base.insertID
111 -- * Transaction handling
86 -- * Transaction handling
112 , withTransaction
87 , withTransaction
113− , withSavepoint
88+ , TransactionMode(..)
91+ , defaultTransactionMode
92+ , defaultIsolationLevel
93+ , defaultReadWriteMode
94+ , withTransactionLevel
95+ , withTransactionMode
114-- , Base.autocommit
96-- , Base.autocommit
117 , rollback
101 , rollback
118 -- * Helper functions
102 -- * Helper functions
@@ -120,27 +104,58 @@ module Database.PostgreSQL.Simple
120 , formatQuery
104 , formatQuery
123−import Data.ByteString.Builder (Builder, byteString, char8)
107+import Blaze.ByteString.Builder
108+ ( Builder, fromByteString, toByteString )
109+import Blaze.ByteString.Builder.Char8 (fromChar)
124−import Control.Applicative ((<$>))
110+import Control.Applicative ((<$>), pure)
125−import Control.Exception as E
111+import Control.Concurrent.MVar
112+import Control.Exception
113+ ( Exception, onException, throw, throwIO, finally )
114+import Control.Monad (foldM)
126import Data.ByteString (ByteString)
115import Data.ByteString (ByteString)
116+import Data.Char(ord)
127import Data.Int (Int64)
117import Data.Int (Int64)
118+import qualified Data.IntMap as IntMap
128import Data.List (intersperse)
119import Data.List (intersperse)
129−import Data.Monoid (mconcat)
120+import Data.Monoid (mappend, mconcat)
121+import Data.Typeable (Typeable)
122+import Database.PostgreSQL.Simple.BuiltinTypes
123+ ( oid2builtin, builtin2typname )
130−import Database.PostgreSQL.Simple.Compat ((<>), toByteString)
124+import Database.PostgreSQL.Simple.Compat ( mask )
131−import Database.PostgreSQL.Simple.Cursor
132import Database.PostgreSQL.Simple.FromField (ResultError(..))
125import Database.PostgreSQL.Simple.FromField (ResultError(..))
133import Database.PostgreSQL.Simple.FromRow (FromRow(..))
126import Database.PostgreSQL.Simple.FromRow (FromRow(..))
134−import Database.PostgreSQL.Simple.ToField (Action(..))
127+import Database.PostgreSQL.Simple.Ok
128+import Database.PostgreSQL.Simple.ToField (Action(..), inQuotes)
135import Database.PostgreSQL.Simple.ToRow (ToRow(..))
129import Database.PostgreSQL.Simple.ToRow (ToRow(..))
136import Database.PostgreSQL.Simple.Types
130import Database.PostgreSQL.Simple.Types
137− ( Binary(..), In(..), Only(..), Query(..), (:.)(..) )
131+ ( Binary(..), In(..), Only(..), Query(..) )
138import Database.PostgreSQL.Simple.Internal as Base
132import Database.PostgreSQL.Simple.Internal as Base
139−import Database.PostgreSQL.Simple.Internal.PQResultUtils
140−import Database.PostgreSQL.Simple.Transaction
141import qualified Database.PostgreSQL.LibPQ as PQ
133import qualified Database.PostgreSQL.LibPQ as PQ
134+import Text.Regex.PCRE.Light (compile, caseless, match)
142import qualified Data.ByteString.Char8 as B
135import qualified Data.ByteString.Char8 as B
143−
136+import qualified Data.Vector as V
137+import Control.Monad.Trans.Reader
138+import Control.Monad.Trans.State.Strict
140+-- | Exception thrown if a 'Query' could not be formatted correctly.
141+-- This may occur if the number of \'@?@\' characters in the query
142+-- string does not match the number of parameters provided.
143+data FormatError = FormatError {
144+ fmtMessage :: String
146+ , fmtParams :: [ByteString]
147+ } deriving (Eq, Show, Typeable)
149+instance Exception FormatError
151+-- | Exception thrown if 'query' is used to perform an @INSERT@-like
152+-- operation, or 'execute' is used to perform a @SELECT@-like operation.
153+data QueryError = QueryError {
156+ } deriving (Eq, Show, Typeable)
158+instance Exception QueryError
145-- | Format a query string.
160-- | Format a query string.
@@ -174,205 +189,103 @@ formatQuery conn q@(Query template) qs
174formatMany :: (ToRow q) => Connection -> Query -> [q] -> IO ByteString
189formatMany :: (ToRow q) => Connection -> Query -> [q] -> IO ByteString
175formatMany _ q [] = fmtError "no rows supplied" q []
190formatMany _ q [] = fmtError "no rows supplied" q []
176formatMany conn q@(Query template) qs = do
191formatMany conn q@(Query template) qs = do
177− case parseTemplate template of
192+ case match re template [] of
178− Just (before, qbits, after) -> do
193+ Just [_,before,qbits,after] -> do
179 bs <- mapM (buildQuery conn q qbits . toRow) qs
194 bs <- mapM (buildQuery conn q qbits . toRow) qs
180− return . toByteString . mconcat $ byteString before :
195+ return . toByteString . mconcat $ fromByteString before :
181− intersperse (char8 ',') bs ++
196+ intersperse (fromChar ',') bs ++
182− [byteString after]
197+ [fromByteString after]
183− Nothing -> fmtError "syntax error in multi-row template" q []
198+ _ -> error "foo"
185−-- Split the input string into three pieces, @before@, @qbits@, and @after@,
186−-- following this grammar:
188−-- start: ^ before qbits after $
189−-- before: ([^?]* [^?\w])? 'VALUES' \s*
190−-- qbits: '(' \s* '?' \s* (',' \s* '?' \s*)* ')'
194−-- \w: [A-Z] | [a-z] | [\x80-\xFF] | '_' | '$' | [0-9]
196−-- This would be much more concise with some sort of regex engine.
197−-- 'formatMany' used to use pcre-light instead of this hand-written parser,
198−-- but pcre is a hassle to install on Windows.
199−parseTemplate :: ByteString -> Maybe (ByteString, ByteString, ByteString)
200−parseTemplate template =
201− -- Convert input string to uppercase, to facilitate searching.
202− search $ B.map toUpper_ascii template
204− -- Search for the next occurrence of "VALUES"
200+ re = compile "^([^?]+\\bvalues\\s*)\
205− search bs =
201+ \(\\(\\s*[?](?:\\s*,\\s*[?])*\\s*\\))\
206− case B.breakSubstring "VALUES" bs of
202+ \([^?]*)$"
207− (x, y)
203+ [caseless]
208− -- If "VALUES" is not present in the string, or any '?' characters
209− -- were encountered prior to it, fail.
210− | B.null y || ('?' `B.elem` x)
213− -- If "VALUES" is preceded by an identifier character (a.k.a. \w),
214− -- try the next occurrence.
215− | not (B.null x) && isIdent (B.last x)
216− -> search $ B.drop 6 y
218− -- Otherwise, we have a legitimate "VALUES" token.
220− -> parseQueryBits $ skipSpace $ B.drop 6 y
222− -- Parse '(' \s* '?' \s* . If this doesn't match
223− -- (and we don't consume a '?'), look for another "VALUES".
225− -- qb points to the open paren (if present), meaning it points to the
226− -- beginning of the "qbits" production described above. This is why we
227− -- pass it down to finishQueryBits.
229− | Just ('(', skipSpace -> bs1) <- B.uncons qb
230− , Just ('?', skipSpace -> bs2) <- B.uncons bs1
231− = finishQueryBits qb bs2
235− -- Parse (',' \s* '?' \s*)* ')' [^?]* .
237− -- Since we've already consumed at least one '?', there's no turning back.
238− -- The parse has to succeed here, or the whole thing fails
239− -- (because we don't allow '?' to appear outside of the VALUES list).
240− finishQueryBits qb bs0
241− | Just (')', bs1) <- B.uncons bs0
242− = if '?' `B.elem` bs1
244− else Just $ slice3 template qb bs1
245− | Just (',', skipSpace -> bs1) <- B.uncons bs0
246− , Just ('?', skipSpace -> bs2) <- B.uncons bs1
247− = finishQueryBits qb bs2
251− -- Slice a string into three pieces, given the start offset of the second
252− -- and third pieces. Each "offset" is actually a tail of the uppercase
253− -- version of the template string. Its length is used to infer the offset.
255− -- It is important to note that we only slice the original template.
256− -- We don't want our all-caps trick messing up the actual query string.
257− slice3 source p1 p2 =
260− (s1, source') = B.splitAt (B.length source - B.length p1) source
261− (s2, source'') = B.splitAt (B.length p1 - B.length p2) source'
263− toUpper_ascii c | c >= 'a' && c <= 'z' = toEnum (fromEnum c - 32)
266− -- Based on the definition of {ident_cont} in src/backend/parser/scan.l
267− -- in the PostgreSQL source. No need to check [a-z], since we converted
268− -- the whole string to uppercase.
269− isIdent c = (c >= '0' && c <= '9')
270− || (c >= 'A' && c <= 'Z')
271− || (c >= '\x80' && c <= '\xFF')
275− -- Based on {space} in scan.l
276− isSpace_ascii c = (c == ' ') || (c >= '\t' && c <= '\r')
278− skipSpace = B.dropWhile isSpace_ascii
205+escapeStringConn :: Connection -> ByteString -> IO (Maybe ByteString)
206+escapeStringConn conn s = withConnection conn $ \c -> do
207+ PQ.escapeStringConn c s
281buildQuery :: Connection -> Query -> ByteString -> [Action] -> IO Builder
209buildQuery :: Connection -> Query -> ByteString -> [Action] -> IO Builder
282−buildQuery conn q template xs =
210+buildQuery conn q template xs = zipParams (split template) <$> mapM sub xs
283− zipParams (split template) <$> mapM (buildAction conn q xs) xs
211+ where quote = inQuotes . fromByteString . maybe undefined id
284− where split s =
212+ sub (Plain b) = pure b
285− -- This part escapes double '??'s to make literal '?'s possible
213+ sub (Escape s) = quote <$> escapeStringConn conn s
286− -- in PostgreSQL queries using the JSON operators: @?@, @?|@ and @?&@
214+ sub (Many ys) = mconcat <$> mapM sub ys
287− let (h,t) = breakOnSingleQuestionMark s
291− else split (B.tail t)
215+ split s = fromByteString h : if B.null t then [] else split (B.tail t)
216+ where (h,t) = B.break (=='?') s
292− zipParams (t:ts) (p:ps) = t <> p <> zipParams ts ps
217+ zipParams (t:ts) (p:ps) = t `mappend` p `mappend` zipParams ts ps
293 zipParams [t] [] = t
218 zipParams [t] [] = t
294− zipParams _ _ = fmtError (show countSingleQs ++
219+ zipParams _ _ = fmtError (show (B.count '?' template) ++
295− " single '?' characters, but " ++
220+ " '?' characters, but " ++
296 show (length xs) ++ " parameters") q xs
221 show (length xs) ++ " parameters") q xs
297− countSingleQs = go 0 template
298− where go i "" = (i :: Int)
299− go i bs = case qms of
300− ("?","?") -> go i nextQMBS
301− ("?",_) -> go (i+1) nextQMBS
303− where qms = B.splitAt 1 qmBS
304− (qmBS,nextQMBS) = B.splitAt 2 qmBS'
305− qmBS' = B.dropWhile (/= '?') bs
307-- | Execute an @INSERT@, @UPDATE@, or other SQL query that is not
223-- | Execute an @INSERT@, @UPDATE@, or other SQL query that is not
308-- expected to return results.
224-- expected to return results.
310-- Returns the number of rows affected.
226-- Returns the number of rows affected.
312−-- Throws 'FormatError' if the query could not be formatted correctly, or
228+-- Throws 'FormatError' if the query could not be formatted correctly.
313−-- a 'SqlError' exception if the backend returns an error.
314execute :: (ToRow q) => Connection -> Query -> q -> IO Int64
229execute :: (ToRow q) => Connection -> Query -> q -> IO Int64
315execute conn template qs = do
230execute conn template qs = do
316 result <- exec conn =<< formatQuery conn template qs
231 result <- exec conn =<< formatQuery conn template qs
317 finishExecute conn template result
232 finishExecute conn template result
234+-- | A version of 'execute' that does not perform query substitution.
235+execute_ :: Connection -> Query -> IO Int64
236+execute_ conn q@(Query stmt) = do
237+ result <- exec conn stmt
238+ finishExecute conn q result
319-- | Execute a multi-row @INSERT@, @UPDATE@, or other SQL query that is not
240-- | Execute a multi-row @INSERT@, @UPDATE@, or other SQL query that is not
320-- expected to return results.
241-- expected to return results.
322−-- Returns the number of rows affected. If the list of parameters is empty,
243+-- Returns the number of rows affected.
323−-- this function will simply return 0 without issuing the query to the backend.
324−-- If this is not desired, consider using the 'Values' constructor instead.
326−-- Throws 'FormatError' if the query could not be formatted correctly, or
327−-- a 'SqlError' exception if the backend returns an error.
329−-- For example, here's a command that inserts two rows into a table
333−-- executeMany c [sql|
334−-- INSERT INTO sometable VALUES (?,?)
335−-- |] [(1, \"hello\"),(2, \"world\")]
338−-- Here's an canonical example of a multi-row update command:
340−-- @
245+-- Throws 'FormatError' if the query could not be formatted correctly.
341−-- executeMany c [sql|
344−-- FROM (VALUES (?,?)) as upd(x,y)
345−-- WHERE sometable.x = upd.x
346−-- |] [(1, \"hello\"),(2, \"world\")]
349executeMany :: (ToRow q) => Connection -> Query -> [q] -> IO Int64
246executeMany :: (ToRow q) => Connection -> Query -> [q] -> IO Int64
350executeMany _ _ [] = return 0
247executeMany _ _ [] = return 0
351executeMany conn q qs = do
248executeMany conn q qs = do
352 result <- exec conn =<< formatMany conn q qs
249 result <- exec conn =<< formatMany conn q qs
353 finishExecute conn q result
250 finishExecute conn q result
355−-- | Execute @INSERT ... RETURNING@, @UPDATE ... RETURNING@, or other SQL
356−-- query that accepts multi-row input and is expected to return results.
357−-- Note that it is possible to write
358−-- @'query' conn "INSERT ... RETURNING ..." ...@
359−-- in cases where you are only inserting a single row, and do not need
360−-- functionality analogous to 'executeMany'.
362−-- If the list of parameters is empty, this function will simply return @[]@
363−-- without issuing the query to the backend. If this is not desired,
364−-- consider using the 'Values' constructor instead.
366−-- Throws 'FormatError' if the query could not be formatted correctly.
367−returning :: (ToRow q, FromRow r) => Connection -> Query -> [q] -> IO [r]
252+finishExecute :: Connection -> Query -> PQ.Result -> IO Int64
368−returning = returningWith fromRow
253+finishExecute _conn q result = do
254+ status <- PQ.resultStatus result
257+ ncols <- PQ.nfields result
259+ then throwIO $ QueryError ("execute resulted in " ++ show ncols ++
262+ nstr <- PQ.cmdTuples result
263+ return $ case nstr of
264+ Nothing -> 0 -- is this appropriate?
265+ Just str -> toInteger str
267+ ncols <- PQ.nfields result
268+ throwIO $ QueryError ("execute resulted in " ++ show ncols ++
270+ PQ.CopyIn -> fail "FIXME: postgresql-simple does not currently support COPY IN"
271+ PQ.CopyOut -> fail "FIXME: postgresql-simple does not currently support COPY OUT"
273+ errormsg <- maybe "" id <$> PQ.resultErrorMessage result
274+ statusmsg <- PQ.resStatus status
275+ state <- maybe "" id <$> PQ.resultErrorField result PQ.DiagSqlstate
276+ throwIO $ SqlError { sqlState = state
277+ , sqlNativeError = fromEnum status
278+ , sqlErrorMsg = B.concat [ "execute: ", statusmsg
281+ toInteger str = B.foldl' delta 0 str
284+ if '0' <= c && c <= '9'
285+ then 10 * acc + fromIntegral (ord c - ord '0')
286+ else error ("finishExecute: not an int: " ++ B.unpack str)
370−-- | A version of 'returning' taking parser as argument
371−returningWith :: (ToRow q) => RowParser r -> Connection -> Query -> [q] -> IO [r]
372−returningWith _ _ _ [] = return []
373−returningWith parser conn q qs = do
374− result <- exec conn =<< formatMany conn q qs
375− finishQueryWith parser conn q result
377-- | Perform a @SELECT@ or other SQL query that is expected to return
290-- | Perform a @SELECT@ or other SQL query that is expected to return
378-- results. All results are retrieved and converted before this
291-- results. All results are retrieved and converted before this
@@ -389,27 +302,17 @@ returningWith parser conn q qs = do
389-- using 'execute' instead of 'query').
302-- using 'execute' instead of 'query').
391-- * 'ResultError': result conversion failed.
304-- * 'ResultError': result conversion failed.
393−-- * 'SqlError': the postgresql backend returned an error, e.g.
394−-- a syntax or type error, or an incorrect table or column name.
395−query :: (ToRow q, FromRow r) => Connection -> Query -> q -> IO [r]
305+query :: (ToRow q, FromRow r)
396−query = queryWith fromRow
306+ => Connection -> Query -> q -> IO [r]
307+query conn template qs = do
308+ result <- exec conn =<< formatQuery conn template qs
309+ finishQuery conn template result
398-- | A version of 'query' that does not perform query substitution.
311-- | A version of 'query' that does not perform query substitution.
399query_ :: (FromRow r) => Connection -> Query -> IO [r]
312query_ :: (FromRow r) => Connection -> Query -> IO [r]
400−query_ = queryWith_ fromRow
402−-- | A version of 'query' taking parser as argument
403−queryWith :: ToRow q => RowParser r -> Connection -> Query -> q -> IO [r]
404−queryWith parser conn template qs = do
405− result <- exec conn =<< formatQuery conn template qs
406− finishQueryWith parser conn template result
408−-- | A version of 'query_' taking parser as argument
409−queryWith_ :: RowParser r -> Connection -> Query -> IO [r]
410−queryWith_ parser conn q@(Query que) = do
313+query_ conn q@(Query que) = do
411 result <- exec conn que
314 result <- exec conn que
412− finishQueryWith parser conn q result
315+ finishQuery conn q result
414-- | Perform a @SELECT@ or other SQL query that is expected to return
317-- | Perform a @SELECT@ or other SQL query that is expected to return
415-- results. Results are streamed incrementally from the server, and
318-- results. Results are streamed incrementally from the server, and
@@ -421,12 +324,6 @@ queryWith_ parser conn q@(Query que) = do
421-- This fold is /not/ strict. The stream consumer is responsible for
324-- This fold is /not/ strict. The stream consumer is responsible for
422-- forcing the evaluation of its result to avoid space leaks.
325-- forcing the evaluation of its result to avoid space leaks.
424−-- This is implemented using a database cursor. As such, this requires
425−-- a transaction. This function will detect whether or not there is a
426−-- transaction in progress, and will create a 'ReadCommitted' 'ReadOnly'
427−-- transaction if needed. The cursor is given a unique temporary name,
428−-- so the consumer may itself call fold.
430-- Exceptions that may be thrown:
327-- Exceptions that may be thrown:
432-- * 'FormatError': the query string could not be formatted correctly.
329-- * 'FormatError': the query string could not be formatted correctly.
@@ -435,9 +332,7 @@ queryWith_ parser conn q@(Query que) = do
435-- using 'execute' instead of 'query').
332-- using 'execute' instead of 'query').
437-- * 'ResultError': result conversion failed.
334-- * 'ResultError': result conversion failed.
439−-- * 'SqlError': the postgresql backend returned an error, e.g.
440−-- a syntax or type error, or an incorrect table or column name.
441fold :: ( FromRow row, ToRow params )
336fold :: ( FromRow row, ToRow params )
442 => Connection
337 => Connection
@@ -447,20 +342,6 @@ fold :: ( FromRow row, ToRow params )
448fold = foldWithOptions defaultFoldOptions
343fold = foldWithOptions defaultFoldOptions
450−-- | A version of 'fold' taking a parser as an argument
451−foldWith :: ( ToRow params )
457− -> (a -> row -> IO a)
459−foldWith = foldWithOptionsAndParser defaultFoldOptions
461−-- | Number of rows to fetch at a time. 'Automatic' currently defaults
462−-- to 256 rows, although it might be nice to make this more intelligent
463−-- based on e.g. the average size of the rows.
464data FetchQuantity
345data FetchQuantity
465 = Automatic
346 = Automatic
466 | Fixed !Int
347 | Fixed !Int
@@ -471,19 +352,12 @@ data FoldOptions
471 transactionMode :: !TransactionMode
352 transactionMode :: !TransactionMode
474−-- | defaults to 'Automatic', and 'TransactionMode' 'ReadCommitted' 'ReadOnly'
475defaultFoldOptions :: FoldOptions
355defaultFoldOptions :: FoldOptions
476defaultFoldOptions = FoldOptions {
356defaultFoldOptions = FoldOptions {
477 fetchQuantity = Automatic,
357 fetchQuantity = Automatic,
478 transactionMode = TransactionMode ReadCommitted ReadOnly
358 transactionMode = TransactionMode ReadCommitted ReadOnly
481−-- | The same as 'fold', but this provides a bit more control over
482−-- lower-level details. Currently, the number of rows fetched per
483−-- round-trip to the server and the transaction mode may be adjusted
484−-- accordingly. If the connection is already in a transaction,
485−-- then the existing transaction is used and thus the 'transactionMode'
486−-- option is ignored.
487foldWithOptions :: ( FromRow row, ToRow params )
361foldWithOptions :: ( FromRow row, ToRow params )
488 => FoldOptions
362 => FoldOptions
489 -> Connection
363 -> Connection
@@ -492,21 +366,9 @@ foldWithOptions :: ( FromRow row, ToRow params )
493 -> (a -> row -> IO a)
367 -> (a -> row -> IO a)
495−foldWithOptions opts = foldWithOptionsAndParser opts fromRow
369+foldWithOptions opts conn template qs a f = do
497−-- | A version of 'foldWithOptions' taking a parser as an argument
498−foldWithOptionsAndParser :: (ToRow params)
505− -> (a -> row -> IO a)
507−foldWithOptionsAndParser opts parser conn template qs a f = do
508 q <- formatQuery conn template qs
370 q <- formatQuery conn template qs
509− doFold opts parser conn template (Query q) a f
371+ doFold opts conn template (Query q) a f
511-- | A version of 'fold' that does not perform query substitution.
373-- | A version of 'fold' that does not perform query substitution.
512fold_ :: (FromRow r) =>
374fold_ :: (FromRow r) =>
@@ -517,14 +379,6 @@ fold_ :: (FromRow r) =>
518fold_ = foldWithOptions_ defaultFoldOptions
380fold_ = foldWithOptions_ defaultFoldOptions
520−-- | A version of 'fold_' taking a parser as an argument
521−foldWith_ :: RowParser r
527−foldWith_ = foldWithOptionsAndParser_ defaultFoldOptions
529foldWithOptions_ :: (FromRow r) =>
383foldWithOptions_ :: (FromRow r) =>
530 FoldOptions
384 FoldOptions
@@ -533,27 +387,18 @@ foldWithOptions_ :: (FromRow r) =>
533 -> a -- ^ Initial state for result consumer.
387 -> a -- ^ Initial state for result consumer.
534 -> (a -> r -> IO a) -- ^ Result consumer.
388 -> (a -> r -> IO a) -- ^ Result consumer.
536−foldWithOptions_ opts conn query' a f = doFold opts fromRow conn query' query' a f
390+foldWithOptions_ opts conn query a f = doFold opts conn query query a f
538−-- | A version of 'foldWithOptions_' taking a parser as an argument
392+
539−foldWithOptionsAndParser_ :: FoldOptions
393+doFold :: ( FromRow row )
540− -> RowParser r
394+ => FoldOptions
542− -> Query -- ^ Query.
543− -> a -- ^ Initial state for result consumer.
544− -> (a -> r -> IO a) -- ^ Result consumer.
546−foldWithOptionsAndParser_ opts parser conn query' a f = doFold opts parser conn query' query' a f
548−doFold :: FoldOptions
550 -> Connection
395 -> Connection
554 -> (a -> row -> IO a)
399 -> (a -> row -> IO a)
556−doFold FoldOptions{..} parser conn _template q a0 f = do
401+doFold FoldOptions{..} conn _template q a f = do
557 stat <- withConnection conn PQ.transactionStatus
402 stat <- withConnection conn PQ.transactionStatus
558 case stat of
403 case stat of
559 PQ.TransIdle -> withTransactionMode transactionMode conn go
404 PQ.TransIdle -> withTransactionMode transactionMode conn go
@@ -571,17 +416,11 @@ doFold FoldOptions{..} parser conn _template q a0 f = do
571 PQ.TransUnknown -> fail "foldWithOpts FIXME: PQ.TransUnknown"
416 PQ.TransUnknown -> fail "foldWithOpts FIXME: PQ.TransUnknown"
572 -- Not sure what this means.
417 -- Not sure what this means.
574− declare =
419+ go = do
575− declareCursor conn q
420+ -- FIXME: what about name clashes with already-declared cursors?
576− fetch cursor a =
421+ _ <- execute_ conn ("DECLARE fold NO SCROLL CURSOR FOR "
577− foldForwardWithParser cursor parser chunkSize f a
422+ `mappend` q)
578−
423+ loop a `finally` execute_ conn "CLOSE fold"
579− go = bracket declare closeCursor $ \cursor ->
580− let loop a = fetch cursor a >>=
586-- FIXME: choose the Automatic chunkSize more intelligently
425-- FIXME: choose the Automatic chunkSize more intelligently
587-- One possibility is to use the type of the results, although this
426-- One possibility is to use the type of the results, although this
@@ -592,6 +431,9 @@ doFold FoldOptions{..} parser conn _template q a0 f = do
592 chunkSize = case fetchQuantity of
431 chunkSize = case fetchQuantity of
593 Automatic -> 256
432 Automatic -> 256
594 Fixed n -> n
433 Fixed n -> n
435+ rs <- query conn "FETCH FORWARD ? FROM fold" (Only chunkSize)
436+ if null rs then return a else foldM f a rs >>= loop
596-- | A version of 'fold' that does not transform a state value.
438-- | A version of 'fold' that does not transform a state value.
597forEach :: (ToRow q, FromRow r) =>
439forEach :: (ToRow q, FromRow r) =>
@@ -600,37 +442,178 @@ forEach :: (ToRow q, FromRow r) =>
600 -> q -- ^ Query parameters.
442 -> q -- ^ Query parameters.
601 -> (r -> IO ()) -- ^ Result consumer.
443 -> (r -> IO ()) -- ^ Result consumer.
603−forEach = forEachWith fromRow
445+forEach conn template qs = fold conn template qs () . const
604{-# INLINE forEach #-}
446{-# INLINE forEach #-}
606−-- | A version of 'forEach' taking a parser as an argument
607−forEachWith :: ( ToRow q )
614−forEachWith parser conn template qs = foldWith parser conn template qs () . const
615−{-# INLINE forEachWith #-}
617-- | A version of 'forEach' that does not perform query substitution.
448-- | A version of 'forEach' that does not perform query substitution.
618forEach_ :: (FromRow r) =>
449forEach_ :: (FromRow r) =>
619 Connection
450 Connection
620 -> Query -- ^ Query template.
451 -> Query -- ^ Query template.
621 -> (r -> IO ()) -- ^ Result consumer.
452 -> (r -> IO ()) -- ^ Result consumer.
623−forEach_ = forEachWith_ fromRow
454+forEach_ conn template = fold_ conn template () . const
624{-# INLINE forEach_ #-}
455{-# INLINE forEach_ #-}
626−forEachWith_ :: RowParser r
457+forM' :: (Ord n, Num n) => n -> n -> (n -> IO a) -> IO [a]
627− -> Connection
458+forM' lo hi m = loop hi []
629− -> (r -> IO ())
460+ loop !n !as
630− -> IO ()
461+ | n < lo = return as
631−forEachWith_ parser conn template = foldWith_ parser conn template () . const
462+ | otherwise = do
632−{-# INLINE forEachWith_ #-}
463+ a <- m n
633−
464+ loop (n-1) (a:as)
466+finishQuery :: (FromRow r) => Connection -> Query -> PQ.Result -> IO [r]
467+finishQuery conn q result = do
468+ status <- PQ.resultStatus result
471+ throwIO $ QueryError "query resulted in a command response" q
473+ ncols <- PQ.nfields result
474+ let unCol (PQ.Col x) = fromIntegral x :: Int
475+ typenames <- V.generateM (unCol ncols)
476+ (\(PQ.Col . fromIntegral -> col) -> do
477+ getTypename conn =<< PQ.ftype result col)
478+ nrows <- PQ.ntuples result
479+ ncols <- PQ.nfields result
480+ forM' 0 (nrows-1) $ \row -> do
481+ let rw = Row row typenames result
482+ case runStateT (runReaderT (unRP fromRow) rw) 0 of
483+ Ok (val,col) | col == ncols -> return val
485+ vals <- forM' 0 (ncols-1) $ \c -> do
486+ v <- PQ.getvalue result row c
487+ return ( typenames V.! unCol c
489+ throw (ConversionFailed
490+ (show (unCol ncols) ++ " values: " ++ show vals)
491+ (show (unCol col) ++ " slots in target type")
492+ "mismatch between number of columns to \
493+ \convert and number in target type")
494+ Errors [] -> throwIO $ ConversionFailed "" "" "unknown error"
495+ Errors [x] -> throwIO x
496+ Errors xs -> throwIO $ ManyErrors xs
498+ellipsis :: ByteString -> ByteString
500+ | B.length bs > 15 = B.take 10 bs `B.append` "[...]"
504+-- | Of the four isolation levels defined by the SQL standard,
505+-- these are the three levels distinguished by PostgreSQL as of version 9.0.
506+-- See <http://www.postgresql.org/docs/9.1/static/transaction-iso.html>
507+-- for more information. Note that prior to PostgreSQL 9.0, 'RepeatableRead'
508+-- was equivalent to 'Serializable'.
511+ = DefaultIsolationLevel -- ^ the isolation level will be taken from
512+ -- PostgreSQL's per-connection
513+ -- @default_transaction_isolation@ variable,
514+ -- which is initialized according to the
515+ -- server's config. The default configuration
516+ -- is 'ReadCommitted'.
520+ deriving (Show, Eq, Ord, Enum, Bounded)
523+ = DefaultReadWriteMode -- ^ the read-write mode will be taken from
524+ -- PostgreSQL's per-connection
525+ -- @default_transaction_read_only@ variable,
526+ -- which is initialized according to the
527+ -- server's config. The default configuration
531+ deriving (Show, Eq, Ord, Enum, Bounded)
533+data TransactionMode = TransactionMode {
534+ isolationLevel :: !IsolationLevel,
535+ readWriteMode :: !ReadWriteMode
536+ } deriving (Show, Eq)
538+defaultTransactionMode :: TransactionMode
539+defaultTransactionMode = TransactionMode
540+ defaultIsolationLevel
541+ defaultReadWriteMode
543+defaultIsolationLevel :: IsolationLevel
544+defaultIsolationLevel = DefaultIsolationLevel
546+defaultReadWriteMode :: ReadWriteMode
547+defaultReadWriteMode = DefaultReadWriteMode
549+-- | Execute an action inside a SQL transaction.
551+-- This function initiates a transaction with a \"@begin
552+-- transaction@\" statement, then executes the supplied action. If
553+-- the action succeeds, the transaction will be completed with
554+-- 'Base.commit' before this function returns.
556+-- If the action throws /any/ kind of exception (not just a
557+-- PostgreSQL-related exception), the transaction will be rolled back using
558+-- 'rollback', then the exception will be rethrown.
559+withTransaction :: Connection -> IO a -> IO a
560+withTransaction = withTransactionMode defaultTransactionMode
562+-- | Execute an action inside a SQL transaction with a given isolation level.
563+withTransactionLevel :: IsolationLevel -> Connection -> IO a -> IO a
564+withTransactionLevel lvl
565+ = withTransactionMode defaultTransactionMode { isolationLevel = lvl }
567+-- | Execute an action inside a SQL transaction with a given transaction mode.
568+withTransactionMode :: TransactionMode -> Connection -> IO a -> IO a
569+withTransactionMode mode conn act =
570+ mask $ \restore -> do
572+ r <- restore act `onException` rollback conn
576+-- | Rollback a transaction.
577+rollback :: Connection -> IO ()
578+rollback conn = execute_ conn "ABORT" >> return ()
580+-- | Commit a transaction.
581+commit :: Connection -> IO ()
582+commit conn = execute_ conn "COMMIT" >> return ()
584+-- | Begin a transaction.
585+begin :: Connection -> IO ()
586+begin = beginMode defaultTransactionMode
588+-- | Begin a transaction with a given isolation level
589+beginLevel :: IsolationLevel -> Connection -> IO ()
590+beginLevel lvl = beginMode defaultTransactionMode { isolationLevel = lvl }
592+-- | Begin a transaction with a given transaction mode
593+beginMode :: TransactionMode -> Connection -> IO ()
594+beginMode mode conn = do
595+ _ <- execute_ conn $! Query (B.concat ["BEGIN", isolevel, readmode])
598+ isolevel = case isolationLevel mode of
599+ DefaultIsolationLevel -> ""
600+ ReadCommitted -> " ISOLATION LEVEL READ COMMITTED"
601+ RepeatableRead -> " ISOLATION LEVEL REPEATABLE READ"
602+ Serializable -> " ISOLATION LEVEL SERIALIZABLE"
603+ readmode = case readWriteMode mode of
604+ DefaultReadWriteMode -> ""
605+ ReadWrite -> " READ WRITE"
606+ ReadOnly -> " READ ONLY"
608+fmtError :: String -> Query -> [Action] -> a
609+fmtError msg q xs = throw FormatError {
612+ , fmtParams = map twiddle xs
614+ where twiddle (Plain b) = toByteString b
615+ twiddle (Escape s) = s
616+ twiddle (Many ys) = B.concat (map twiddle ys)
@@ -658,11 +641,9 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
659-- > import Database.PostgreSQL.Simple
642-- > import Database.PostgreSQL.Simple
662-- > hello = do
644-- > hello = do
663−-- > conn <- connectPostgreSQL ""
645+-- > conn <- connect defaultConnectInfo
664−-- > [Only i] <- query_ conn "select 2 + 2"
646+-- > query conn "select 2 + 2"
667-- A 'Query' value does not represent the actual query that will be
648-- A 'Query' value does not represent the actual query that will be
668-- executed, but is a template for constructing the final query.
649-- executed, but is a template for constructing the final query.
@@ -709,7 +690,7 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
709-- Automated type inference means that you will often be able to avoid
690-- Automated type inference means that you will often be able to avoid
710-- supplying explicit type signatures for the elements of a tuple.
691-- supplying explicit type signatures for the elements of a tuple.
711-- However, sometimes the compiler will not be able to infer your
692-- However, sometimes the compiler will not be able to infer your
712−-- types. Consider a case where you write a numeric literal in a
693+-- types. Consider a care where you write a numeric literal in a
713-- parameter tuple:
694-- parameter tuple:
715-- > query conn "select ? + ?" (40,2)
696-- > query conn "select ? + ?" (40,2)
@@ -723,30 +704,15 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
723-- The same kind of problem can arise with string literals if you have
704-- The same kind of problem can arise with string literals if you have
724-- the @OverloadedStrings@ language extension enabled. Again, just
705-- the @OverloadedStrings@ language extension enabled. Again, just
725-- use an explicit type signature if this happens.
706-- use an explicit type signature if this happens.
727−-- Finally, remember that the compiler must be able to infer the type
728−-- of a query's /results/ as well as its parameters. We might like
729−-- the following example to work:
731−-- > print =<< query_ conn "select 2 + 2"
733−-- Unfortunately, while a quick glance tells us that the result type
734−-- should be a single row containing a single numeric column, the
735−-- compiler has no way to infer what the types are. We can easily fix
736−-- this by providing an explicit type annotation:
738−-- > xs <- query_ conn "select 2 + 2"
739−-- > print (xs :: [Only Int])
741-- $only_param
708-- $only_param
743-- Haskell lacks a single-element tuple type, so if you have just one
710-- Haskell lacks a single-element tuple type, so if you have just one
744−-- value you want substituted into a query or a single-column result,
711+-- value you want substituted into a query, what should you do?
745−-- what should you do?
747-- The obvious approach would appear to be something like this:
713-- The obvious approach would appear to be something like this:
749−-- > instance (ToField a) => ToRow a where
715+-- > instance (Param a) => QueryParam a where
752-- Unfortunately, this wreaks havoc with type inference, so we take a
718-- Unfortunately, this wreaks havoc with type inference, so we take a
@@ -757,9 +723,6 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
758-- > execute conn "insert into users (first_name) values (?)"
724-- > execute conn "insert into users (first_name) values (?)"
759-- > ["Nuala"]
725-- > ["Nuala"]
761−-- A row of /n/ query results is represented using an /n/-tuple, so
762−-- you should use 'Only' to represent a single-column result.
@@ -777,7 +740,7 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
777-- Here's an example:
740-- Here's an example:
779-- > query conn "select * from users where first_name in ?" $
742-- > query conn "select * from users where first_name in ?" $
780−-- > Only $ In ["Anna", "Boris", "Carla"]
743+-- > In ["Anna", "Boris", "Carla"]
782-- If your 'In'-wrapped list is empty, the string @\"(null)\"@ will be
745-- If your 'In'-wrapped list is empty, the string @\"(null)\"@ will be
783-- substituted instead, to ensure that your clause remains
746-- substituted instead, to ensure that your clause remains
@@ -805,7 +768,7 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
805-- * There must be no other \"@?@\" characters anywhere in your
768-- * There must be no other \"@?@\" characters anywhere in your
806-- template.
769-- template.
808−-- * There must be one or more \"@?@\" in the parentheses.
771+-- * There must one or more \"@?@\" in the parentheses.
810-- * Extra white space is fine.
773-- * Extra white space is fine.
@@ -826,22 +789,6 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
826-- > insert into users (first_name,last_name) values
789-- > insert into users (first_name,last_name) values
827-- > ('Boris','Karloff'),('Ed','Wood')
790-- > ('Boris','Karloff'),('Ed','Wood')
831−-- PostgreSQL supports returning values from data manipulation statements
832−-- such as @INSERT@ and @UPDATE@. You can use these statements by
833−-- using 'query' instead of 'execute'. For multi-tuple inserts,
834−-- use 'returning' instead of 'executeMany'.
836−-- For example, were there an auto-incrementing @id@ column and
837−-- timestamp column @t@ that defaulted to the present time for the
838−-- @sales@ table, then the following query would insert two new
839−-- sales records and also return their new @id@s and timestamps.
841−-- > let q = "insert into sales (amount, label) values (?,?) returning id, t"
842−-- > xs :: [(Int, UTCTime)] <- query conn q (15,"Sawdust")
843−-- > ys :: [(Int, UTCTime)] <- returning conn q [(20,"Chips"),(300,"Wood")]
845-- $result
792-- $result
847-- The 'query' and 'query_' functions return a list of values in the
794-- The 'query' and 'query_' functions return a list of values in the
@@ -876,7 +823,7 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
877-- Although SQL can accommodate @NULL@ as a value for any of these
824-- Although SQL can accommodate @NULL@ as a value for any of these
878-- types, Haskell cannot. If your result contains columns that may be
825-- types, Haskell cannot. If your result contains columns that may be
879−-- @NULL@, be sure that you use 'Maybe' in those positions of your
826+-- @NULL@, be sure that you use 'Maybe' in those positions of of your
882-- > (Text, Maybe Int, Int)
829-- > (Text, Maybe Int, Int)
@@ -902,7 +849,7 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
902-- all values of the given PostgreSQL type is considered \"compatible\".
849-- all values of the given PostgreSQL type is considered \"compatible\".
903-- For instance, you can always extract a PostgreSQL 16-bit @SMALLINT@
850-- For instance, you can always extract a PostgreSQL 16-bit @SMALLINT@
904-- column to a Haskell 'Int'. The Haskell 'Float' type can accurately
851-- column to a Haskell 'Int'. The Haskell 'Float' type can accurately
905−-- represent a @SMALLINT@, so it is considered compatible with those types.
852+-- represent a @SMALLINT@, so it is considered compatble with those types.
907-- * A numeric compatibility check is based only on the type of a
854-- * A numeric compatibility check is based only on the type of a
908-- column, /not/ on its values. For instance, a PostgreSQL 64-bit
855-- column, /not/ on its values. For instance, a PostgreSQL 64-bit
@@ -916,3 +863,25 @@ forEachWith_ parser conn template = foldWith_ parser conn template () . const
916-- UTF-8. If you use some other encoding, decoding may fail or give
863-- UTF-8. If you use some other encoding, decoding may fail or give
917-- wrong results. In such cases, write a @newtype@ wrapper and a
864-- wrong results. In such cases, write a @newtype@ wrapper and a
918-- custom 'Result' instance to handle your encoding.
865-- custom 'Result' instance to handle your encoding.
867+getTypename :: Connection -> PQ.Oid -> IO ByteString
868+getTypename conn@Connection{..} oid =
869+ case oid2builtin oid of
870+ Just builtin -> return $! builtin2typname builtin
871+ Nothing -> modifyMVar connectionObjects $ \oidmap -> do
872+ case IntMap.lookup (oid2int oid) oidmap of
873+ Just name -> return (oidmap, name)
875+ names <- query conn "SELECT typname FROM pg_type WHERE oid=?"
877+ name <- case names of
878+ [] -> return $ throw SqlError {
879+ sqlNativeError = -1,
880+ sqlErrorMsg = "invalid type oid",
883+ [Only x] -> return x
884+ _ -> fail "typename query returned more than one result"
885+ -- oid is a primary key, so the query should
886+ -- never return more than one result
887+ return (IntMap.insert (oid2int oid) name oidmap, name)