postgresql-orm (empty) → 0.1
raw patch · 20 files changed
+4571/−0 lines, 20 filesdep +basedep +blaze-builderdep +bytestringsetup-changed
Dependencies added: base, blaze-builder, bytestring, directory, filepath, ghc-prim, mtl, postgresql-simple, process, text, time, transformers, unix, vector
Files
- Data/GetField.hs +240/−0
- Data/RequireSelector.hs +24/−0
- Database/PostgreSQL/Describe.hs +86/−0
- Database/PostgreSQL/Devel.hs +206/−0
- Database/PostgreSQL/Escape.hs +257/−0
- Database/PostgreSQL/Migrate.hs +154/−0
- Database/PostgreSQL/Migrations.hs +415/−0
- Database/PostgreSQL/ORM.hs +29/−0
- Database/PostgreSQL/ORM/Association.hs +540/−0
- Database/PostgreSQL/ORM/CreateTable.hs +104/−0
- Database/PostgreSQL/ORM/DBSelect.hs +383/−0
- Database/PostgreSQL/ORM/Model.hs +1083/−0
- Database/PostgreSQL/ORM/SqlType.hs +108/−0
- Database/PostgreSQL/ORM/Validations.hs +34/−0
- LICENSE +675/−0
- Setup.hs +2/−0
- man/man1/pg_migrate.1 +90/−0
- man/man5/pg_migrate.5 +44/−0
- pg_migrate.hs +28/−0
- postgresql-orm.cabal +69/−0
+ Data/GetField.hs view
@@ -0,0 +1,240 @@+{-# LANGUAGE Safe #-}+{-# LANGUAGE DefaultSignatures #-}+{-# LANGUAGE FlexibleContexts #-}+{-# LANGUAGE FlexibleInstances #-}+{-# LANGUAGE FunctionalDependencies #-}+{-# LANGUAGE MultiParamTypeClasses #-}+{-# LANGUAGE OverlappingInstances #-}+{-# LANGUAGE TypeOperators #-}+{-# LANGUAGE UndecidableInstances #-}++-- | Functions to extract a field of a particular type from a+-- 'Generic' data structure, when the data structure contains exactly+-- one field of the given type. Only works for types with exactly one+-- constructor (not variant types).+--+-- An example of usage:+--+-- > data MyType = MyType { myString :: String -- position 0+-- > , myInt :: Int -- position 1+-- > , myBool :: Bool -- position 2+-- > , myMaybeChar :: Maybe Char -- position 3+-- > , myMaybeString :: Maybe String -- position 4+-- > } deriving (Show, Generic)+-- > +-- > myType :: MyType+-- > myType = MyType "my type" 21 True Nothing (Just "maybe string")+--+-- >>> getFieldVal ExtractId myType :: String+-- "my type"+-- >>> getFieldVal ExtractId myType :: Int+-- 21+-- >>> getFieldVal ExtractMaybe myType :: Maybe Char+-- Nothing+-- >>> getFieldVal ExtractMaybe myType :: Maybe Int+-- Just 21+-- >>> getFieldVal ExtractMaybe myType :: Maybe String -- ambiguous+-- <interactive>:5:1: Couldn't match type `THasMany' with `THasOne'+-- >>> getFieldPos' ExtractId (undefined :: MyType) (undefined :: Bool)+-- 2+-- >>> getFieldPos' ExtractMaybe (undefined :: MyType) (undefined :: Maybe Bool)+-- 2+-- >>> getFieldPos' ExtractMaybe myType () -- No field has type ()+-- <interactive>:8:1: Couldn't match type `THasNone' with `THasOne'+module Data.GetField (+ GetField(..), ExtractId(..), ExtractMaybe(..), getFieldPos'+ -- * Internals+ , THasOne(..), THasNone(..), THasMany(..), Extractor(..), GGetField(..)+ ) where++import GHC.Generics++-- | Dirty trick to construct "less specific" overlapping instances by+-- making a class argument a simple type variable, but constraining+-- that variable to be a particular type. E.g., neither of the+-- following two instances is more specific than the other, because+-- @NO@ is not more general than @YES@:+--+-- > class MyClass a b c | a b -> c where myClass :: a -> b -> c ()+-- > instance MyClass a a YES where myClass _ _ = YES ()+-- > instance MyClass a b NO where myClass _ _ = NO ()+--+-- Hence, attempting to use the first instance will generate a+-- compilation error rather than inferring the type of c as YES. On+-- the other hand, of the following two instances, the first is more+-- specific than the second:+--+-- > instance MyClass a a YES where+-- > myClass _ _ = YES ()+-- > instance (TypeGCast NO c) => MyClass a b c where+-- > myClass _ _ = typeGCast $ NO ()+--+-- That's because @c@ is more general than @YES@. The key to this+-- working is that an instance context--i.e., @(TypeGCast NO c)@--is+-- never consulted during instance selection, only to validate an+-- already-selected most-specific instance.+--+-- Note that @YES@ and @NO@ in these examples have kind @* -> *@.+-- Hence the @G@ in @TypeGCast@. The same trick is equally applicable+-- to types of kind @*@, we just don't happen to need that in this+-- module.+class TypeGCast f g | f -> g where+ typeGCast :: f p -> g p+instance TypeGCast f f where+ typeGCast = id++-- | Exactly one matching field has been found.+newtype THasOne a = THasOne { fromTHasOne :: a } deriving (Show)+-- | Zero matching fields have been found.+data THasNone a = THasNone deriving (Show)+-- | More than one matching field has been found.+newtype THasMany a = THasMany { fromTHasMany :: [a] } deriving (Show)++class GCombine a b c | a b -> c where+ gCombine :: a p -> b p -> c p+instance GCombine THasOne THasNone THasOne where+ {-# INLINE gCombine #-}+ gCombine j _ = j+instance GCombine THasNone THasOne THasOne where+ {-# INLINE gCombine #-}+ gCombine _ j = j+instance GCombine THasNone THasNone THasNone where+ -- Should never be evaluated, so no need to inline it+ gCombine _ _ = THasNone+instance GCombine THasOne THasOne THasMany where+ {-# INLINE gCombine #-}+ gCombine (THasOne a) (THasOne b) = THasMany [a,b]+instance GCombine THasMany THasMany THasMany where+ {-# INLINE gCombine #-}+ gCombine (THasMany as) (THasMany bs) = THasMany (as ++ bs)+instance GCombine THasNone THasMany THasMany where+ {-# INLINE gCombine #-}+ gCombine _ hm = hm+instance GCombine THasMany THasNone THasMany where+ {-# INLINE gCombine #-}+ gCombine hm _ = hm+instance GCombine THasOne THasMany THasMany where+ {-# INLINE gCombine #-}+ gCombine (THasOne a) (THasMany as) = THasMany (a:as)+instance GCombine THasMany THasOne THasMany where+ {-# INLINE gCombine #-}+ gCombine (THasMany as) (THasOne a) = THasMany (as++[a])++class GCount f where gCount :: f p -> (Int, [Int])+instance GCount THasOne where gCount _ = (1, [0])+instance GCount THasMany where gCount _ = (1, [0])+instance GCount THasNone where gCount _ = (1, [])++-- | Class of types used as tag arguments to 'gGetFieldVal' and+-- 'gGetFieldPos'. @f@ should be a new unit type of kind @* -> *@,+-- used to designate the type of extraction you want. Then instances+-- should be defined to transform each type @a@ you want to extract to+-- some type @r@, with @g@ set to 'THasOne'.+--+-- For example, 'ExtractMaybe' is a type to convert types @a@ and+-- @Maybe a@ both to type @Maybe a@ (i.e., type argument @r@ is @Maybe+-- a@).+--+-- > data ExtractMaybe a = ExtractMaybe+-- > instance Extractor ExtractMaybe a (Maybe a) THasOne where+-- > extract _ = THasOne . Just+-- > instance Extractor ExtractMaybe (Maybe a) (Maybe a) THasOne where+-- > extract _ = THasOne+--+-- Note that there is already a default general instance returning+-- 'THasNone'. Hence, you do not need to define one. Otherwise, you+-- would have to define an overlapping instance such as:+--+-- > instance Extractor ExtractMaybe a b THasZero where -- Incorrect+-- > extract _ = THasNone+--+-- (Except the above wouldn't quite work anyway given the rules for+-- overlapping instances.) So just assume that any instance you don't+-- explicitly define for your 'Extractor' will automatically fall back+-- to 'THasNone'.+class Extractor f a r g | f a r -> g where+ extract :: f r -> a -> g r+ extractCount :: f r -> a -> (Int, [Int])+ default extractCount :: (GCount g) => f r -> a -> (Int, [Int])+ extractCount fr a = gCount (extract fr a)+instance (TypeGCast THasNone g) => Extractor f a r g where+ extract _ _ = typeGCast THasNone+ extractCount _ _ = gCount THasNone++-- | Generlized extraction of a field from a 'Generic' data structure.+-- Argument @rep@ should generally be the type @'Rep' t@ for some data+-- type @t@ whose fields you want to extract. @r@ is the result type+-- you want back from the extraction. @f@ should be defined such that+-- there is an instance of @'Extractor' f a r THasOne@ for each type+-- @a@ you want to convert to @r@ and extract.+class GGetField f rep r g | f rep r -> g where+ gGetFieldVal :: f r -> rep p -> g r+ -- ^ Returns zero, one, or multiple values of type @f@ wrapped in+ -- 'THasOne', 'THasNone', or 'THasMany' respectively.+ gGetFieldPos :: f r -> rep p -> (Int, [Int])+ -- ^ Returns @(total, positions)@ where @total@ is the total number+ -- of fields (matching or not) in the structure and @positions@ is a+ -- list of zero-based field numbers of the fields matching target+ -- type @f r@.+instance (Extractor f c r g) => GGetField f (K1 i c) r g where+ {-# INLINE gGetFieldVal #-}+ gGetFieldVal f (K1 c) = extract f c+ gGetFieldPos f (K1 c) = extractCount f c+instance (GGetField f a1 r g1, GGetField f a2 r g2, GCombine g1 g2 g) =>+ GGetField f (a1 :*: a2) r g where+ {-# INLINE gGetFieldVal #-}+ gGetFieldVal f (a1 :*: a2) =+ gCombine (gGetFieldVal f a1) (gGetFieldVal f a2)+ gGetFieldPos f ~(a1 :*: a2) = (n1 + n2, p1 ++ map (n1 +) p2)+ where (n1, p1) = gGetFieldPos f a1+ (n2, p2) = gGetFieldPos f a2+instance (GGetField f a r g) => GGetField f (M1 i c a) r g where+ {-# INLINE gGetFieldVal #-}+ gGetFieldVal f (M1 a) = gGetFieldVal f a+ gGetFieldPos f ~(M1 a) = gGetFieldPos f a+++class (Generic a, GGetField f (Rep a) r THasOne) => GetField f a r where+ -- | Extract the single field matching 'Extractor' @f r@ from a+ -- 'Generic' data structure @a@ with exactly one constructor.+ getFieldVal :: f r -> a -> r+ -- | Extract the 0-based position of the single field matching+ -- 'Extractor' @f r@ within 'Generic' data structure @a@.+ -- Non-strict in both arguments.+ getFieldPos :: f r -> a -> Int+instance (Generic a, GGetField f (Rep a) r THasOne) => GetField f a r where+ {-# INLINE getFieldVal #-}+ getFieldVal f a = fromTHasOne $ gGetFieldVal f (from a)+ getFieldPos f a = head $ snd $ gGetFieldPos f (from a)++-- | A variant of 'getFieldPos' in which the type of the field is+-- supplied as a non-strict argument. This may be easier than+-- typecasting the extractor argument. For example, to extract the+-- 'Int' from a structure with a single 'Int' field:+--+-- @+-- getFieldPos' 'ExtractId' myStruct ('undefined' :: 'Int')+-- @+getFieldPos' :: (Generic a, GGetField f (Rep a) r THasOne) =>+ (f ()) -> a -> r -> Int+getFieldPos' f a r = getFieldPos (fixType f r) a+ where fixType :: f () -> r -> f r+ fixType _ _ = undefined++-- | An extractor that matches an exact field type.+data ExtractId r = ExtractId deriving (Show)+instance Extractor ExtractId a a THasOne where+ {-# INLINE extract #-}+ extract _ = THasOne++-- | An extractor that matches either type @r@ or type @Maybe r@, and,+-- in the former case, wraps @Just@ around the value so as always to+-- return type @Maybe r@.+data ExtractMaybe r = ExtractMaybe+instance Extractor ExtractMaybe a (Maybe a) THasOne where+ {-# INLINE extract #-}+ extract _ = THasOne . Just+instance Extractor ExtractMaybe (Maybe a) (Maybe a) THasOne where+ {-# INLINE extract #-}+ extract _ = THasOne+
+ Data/RequireSelector.hs view
@@ -0,0 +1,24 @@+{-# LANGUAGE FlexibleInstances, UndecidableInstances #-}++module Data.RequireSelector (RequireSelector) where++import GHC.Generics++-- | There are intentionally no members of this class, so that placing+-- it in a context will always cause an error.+class IntentionallyCauseError a++-- | The point of this class is to ensure that you are using data+-- types defined with record selectors (i.e., @data Foo = Foo { unFoo+-- :: Int }@ as opposed to @data Foo = Foo Int@).+--+-- Unfortunately, "GHC.Generics" makes the 'NoSelector' type a member+-- of the 'Selector' class. Hence, if you want to ensure a type @a@+-- is /not/ 'NoSelector', use the context @(RequireSelector a) =>@.+--+-- If you see a compilation error involving @RequireSelector@ or+-- @IntentionallyCauseError@, it means you failed to define one of+-- your datatypes using record selector syntax.+class RequireSelector a+instance (IntentionallyCauseError NoSelector) => RequireSelector NoSelector+instance RequireSelector a
+ Database/PostgreSQL/Describe.hs view
@@ -0,0 +1,86 @@+{-# LANGUAGE OverloadedStrings #-}++-- | Utility function for describing a table in the database.+module Database.PostgreSQL.Describe (+ ColumnInfo(..), describeTable+ ) where++import Control.Monad+import qualified Data.ByteString as S+import Data.Int+import qualified Data.Vector as V+import qualified Database.PostgreSQL.Simple.TypeInfo.Static as PG+import Database.PostgreSQL.Simple+import Database.PostgreSQL.Simple.TypeInfo+import Database.PostgreSQL.Simple.Types++data ColumnInfo = ColumnInfo {+ colNum :: !Int16+ -- ^ Internal column number used by PostgreSQL. Generally these+ -- will be consecutive starting from 1, but this may not be the+ -- case if you have altered a table to delete columns.+ , colName :: S.ByteString+ -- ^ Name of the column+ , colType :: !TypeInfo+ -- ^ Type of the column+ , colNotNull :: !Bool+ -- ^ If 'True', the database cannot contain null. (This+ -- constraint should always be accurate.)+ , colPrimary :: !Bool+ -- ^ 'True' if this column (and only this column) constitutes the+ -- primary key of the table. Always 'False' if the primary key+ -- comprises multiple columns (even if this is one of those+ -- columns).+ , colUnique :: !Bool+ -- ^ 'True' if there is a uniqueness constraint on this column.+ -- Not 'True' if this column is part of a uniqueness constraint+ -- involving multiple columns. (Such multi-column uniqueness+ -- constraints are not reported by this interface.)+ , colReferences :: !(Maybe S.ByteString)+ -- ^ If this there is a foreign key constraint on this column (and+ -- the constraint does not span multiple columns), report the+ -- table referenced by this column.+ } deriving (Show)++defColInfo :: ColumnInfo+defColInfo = ColumnInfo {+ colNum = 0+ , colName = S.empty+ , colType = PG.void+ , colNotNull = False+ , colPrimary = False+ , colUnique = False+ , colReferences = Nothing+ }++-- | Returns a list of 'ColumnInfo' structures for a particular table.+-- Not all information about a table is returned. In particular,+-- constraints that span columns are ignored.+describeTable :: Connection -> S.ByteString -> IO [ColumnInfo]+describeTable cn t = do+ [(Only tbloid)] <- query cn "select oid from pg_class where relname = ?"+ (Only t)+ cs0 <- query cn "select attnum, attname, atttypid, attnotnull\+ \ from pg_attribute\+ \ where attrelid = ? and attisdropped = 'f' and attnum > 0\+ \ order by attnum"+ (Only (tbloid :: Oid))+ cs1 <- forM cs0 $ \ (num, name, typ, notnull) -> do+ ti <- getTypeInfo cn typ+ return defColInfo {+ colNum = num, colName = name, colType = ti, colNotNull = notnull+ }+ constraints <- query cn "select contype, conkey, relname\+ \ from pg_constraint left join pg_class\+ \ on confrelid = pg_class.oid\+ \ where conrelid = ?"+ (Only tbloid)+ let _ = constraints :: [(String, V.Vector Int16, Maybe S.ByteString)]+ return $ map (\c -> foldl appConstr c constraints) cs1+ where appConstr ci (ct, ck, mn)+ | V.length ck == 1, colNum ci == ck V.! 0 = appConstr1 ci ct mn+ | otherwise = ci+ appConstr1 ci "p" _ = ci { colPrimary = True }+ appConstr1 ci "u" _ = ci { colUnique = True }+ appConstr1 ci "f" n@(Just _) = ci { colReferences = n }+ appConstr1 ci _ _ = ci
+ Database/PostgreSQL/Devel.hs view
@@ -0,0 +1,206 @@+{-# LANGUAGE OverloadedStrings #-}++-- | Functions for initializing self-contained local postgreSQL+-- database clusters (useful in development more than production).+module Database.PostgreSQL.Devel (+ createLocalDB, configLocalDB, startLocalDB+ , initLocalDB, stopLocalDB, setLocalDB+ , withTempDB+ , resetConnection+ ) where++import Control.Exception+import Control.Monad+import Data.Functor+import Data.List+import Database.PostgreSQL.Simple+import System.Directory+import System.Exit+import System.FilePath+import System.IO+import System.IO.Error+import System.Posix.Env+import System.Posix.Temp+import System.Process++isNonEmptyDir :: FilePath -> IO Bool+isNonEmptyDir dir =+ catchJust (\e -> if isDoesNotExistError e then Just () else Nothing)+ ((> 2) . length <$> getDirectoryContents dir)+ (const $ return False)++addDirectives :: [(String, String)] -> [String] -> [String]+addDirectives directives [] = map snd directives+addDirectives directives (cl:cls)+ | Just l <- lookup directive directives =+ (if comment then [l, cl] else [l]) +++ addDirectives (directives \\ [(directive,l)]) cls+ | otherwise = cl : addDirectives directives cls+ where (comment, directive)+ | '#':clr <- cl, [(d,_)] <- lex clr = (True, d)+ | [(d,_)] <- lex cl = (False, d)+ | otherwise = (False, "")++-- | Set configuration parameters on a database by editing the+-- @postgresql.conf@ file. Takes the database directory and a list of+-- @(@/parameter/@,@ /full-line/@)@ pairs. For example, when creating+-- a throw-away database cluster you later intend to discard, you+-- might say:+--+-- > configLocalDB dbpath [("fsync", "fsync = off")]+--+-- Note that the second element of each pair is the complete+-- configuration line. It is not correct to say:+--+-- > configLocalDB dbpath [("fsync", "off")] -- INCORRECT+--+configLocalDB :: FilePath -> [(String, String)] -> IO ()+configLocalDB dir directives = do+ let confpath = dir </> "postgresql.conf"+ oldconf <- lines <$> readFile confpath+ let conf = unlines $ addDirectives directives oldconf+ length conf `seq` writeFile confpath conf++pgDirectives :: FilePath -> [(String, String)]+pgDirectives dir = [+ ("unix_socket_directory", "unix_socket_directory = '" ++ q dir ++ "'")+ , ("logging_collector", "logging_collector = yes")+ , ("listen_addresses", "listen_addresses = ''")]+ where q ('\'':t) = "''" ++ q t+ q (h:t) = h : q t+ q [] = ""++-- | Create a directory for a local database cluster entirely+-- self-contained within one directory. This is accomplished by+-- creating a new PostgreSQL database cluster in the directory and+-- setting the following configuration options in @postgresql.conf@:+--+-- * @unix_socket_directory@ is set to the database directory itself,+-- so that no permissions are required on global directories such as+-- @\/var\/run@.+--+-- * @listen_address@ is set to empty (i.e., @\'\'@), so that no TCP+-- socket is bound, avoiding conflicts with any other running instaces+-- of PostgreSQL.+--+-- * @logging_collector@ is set to @yes@, so that all message logs are+-- kept in the @pg_log@ subdirectory of the directory you specified.+--+-- Note this function does /not/ start a postgres server after+-- creating the directory. You will seperately need to start the+-- server using 'startLocalDB' or 'initLocalDB'. (And note that+-- 'initLocalDB' already calls @createLocalDB@ if the directory does+-- not exist or is empty. Hence the primary use of this function is+-- if you want to call 'configLocalDB' between 'createLocalDB' and+-- 'startLocalDB'.)+createLocalDB :: FilePath -> IO ()+createLocalDB dir = do+ (exit, _, err) <- readProcessWithExitCode "pg_ctl"+ ["-D", dir, "-o", "--no-locale", "init"] ""+ when (exit /= ExitSuccess) $ fail err+ dir' <- canonicalizePath dir+ writeFile (dir </> "README_BEFORE_DELETING") $+ "## IMPORTANT: Run the following command before deleting this " +++ "directory ##\n\n" +++ "pg_ctl -D " ++ showCommandForUser dir' [] ++ " stop -m immediate\n\n"+ configLocalDB dir $ pgDirectives dir'++systemNoStdout :: String -> [String] -> IO ExitCode+systemNoStdout prog args =+ bracket (openFile "/dev/null" ReadWriteMode) hClose $ \devnull -> do+ let cp = (proc prog args) { std_in = UseHandle devnull+ , std_out = UseHandle devnull }+ (_,_,_,pid) <- createProcess cp+ waitForProcess pid++-- | Start a local database if the server is not already running.+-- Otherwise, does nothing, but returns a 'ConnectInfo' in either+-- case. The database server will continue running after the current+-- process exits (but see 'stopLocalDB').+startLocalDB :: FilePath -> IO ConnectInfo+startLocalDB dir0 = do+ dir <- canonicalizePath dir0+ (e0, _, _) <- readProcessWithExitCode "pg_ctl" ["status", "-D", dir] ""+ when (e0 /= ExitSuccess) $ do+ e1 <- systemNoStdout "pg_ctl" ["start", "-w", "-D", dir]+ when (e1 /= ExitSuccess) $ fail "could not start postgres"+ return defaultConnectInfo { connectHost = dir+ , connectUser = ""+ , connectDatabase = "postgres"+ }++-- | A combination of 'createLocalDB' and 'startLocalDB'.+--+-- The parameter is a PostgreSQL data directory. If the directory is+-- empty or does not exist, this function creates a new database+-- cluster (via 'createLocalDB'). Then, if a database server is not+-- already running for the directory, starts a server. No matter+-- what, returns a 'ConnectInfo' that will connect to the server+-- running on this local database.+--+-- Note that if @initLocalDB@ starts a postgres server, the server+-- process will continue running after the process that called+-- @initLocalDB@ exits. This is normally fine. Since multiple client+-- processes may access the same PostgreSQL database, it makes sense+-- for the first client to start the database and no one to stop it.+-- See 'stopLocalDB' if you wish to stop the server process (which you+-- should always do before deleting a test cluster). See also+-- 'withTempDB' to create a temporary cluster for the purposes of+-- running a test suite.+initLocalDB :: FilePath -> IO ConnectInfo+initLocalDB dir = do+ exists <- isNonEmptyDir dir+ unless exists $ createLocalDB dir+ startLocalDB dir++-- | Stop the server for a local database cluster entirely+-- self-contained within one directory. You must call this before+-- deleting the directory, or else stray postgres processes will+-- linger forever. If the argument is the empty string, looks for the+-- database directory in the @PGDATA@ environment variable.+stopLocalDB :: FilePath -> IO ()+stopLocalDB dir0 = do+ dir <- if not (null dir0) then return dir0 else do+ mpgd <- getEnv "PGDATA"+ case mpgd of Just pgd -> return pgd+ _ -> fail "stopLocalDB: must specify database"+ e <- systemNoStdout "pg_ctl" ["stop", "-D", dir, "-m", "fast"]+ when (e /= ExitSuccess) $ fail "could not stop postgres"++-- | Set environment variables to make a local database cluster the+-- default. Also returns shell commands you can eval or cut-and-paste+-- into your shell to make @pg_ctl@ and @psql@ access a local database+-- cluster.+setLocalDB :: FilePath -> IO String+setLocalDB dir0 = do+ dir1 <- canonicalizePath dir0+ setEnv "PGHOST" dir1 True+ setEnv "PGDATA" dir1 True+ setEnv "PGDATABASE" "postgres" True+ let dir = showCommandForUser dir1 []+ msh <- getEnv "SHELL"+ return $ case msh of Just sh | isSuffixOf "csh" sh ->+ "setenv PGDATA " ++ dir ++ "; setenv PGHOST " ++ dir+ _ -> "export PGDATA=" ++ dir ++ " PGHOST=" ++ dir++-- | Run a function with a completely fresh database cluster that gets+-- deleted on return. Since the entire database is blown away when+-- the function returns, @withTempDB@ is obviously only useful for+-- test suites.+withTempDB :: (ConnectInfo -> IO a) -> IO a+withTempDB f = bracket createdir removeDirectoryRecursive $ \d ->+ flip finally (stopLocalDB d) $ do+ createLocalDB d+ configLocalDB d [("fsync", "fsync = off")+ , ("synchronous_commit", "synchronous_commit = off")+ , ("full_page_writes", "full_page_writes = off")]+ initLocalDB d >>= f+ where createdir = do+ tmp <- getTemporaryDirectory+ mkdtemp $ tmp </> "db."++-- | Reset a connection to its default state before re-cycling it for+-- another thread or request.+resetConnection :: Connection -> IO ()+resetConnection c = (void $ execute_ c "DISCARD ALL") `catch` \SqlError{} ->+ void $ execute_ c "ROLLBACK" >> execute_ c "DISCARD ALL"
+ Database/PostgreSQL/Escape.hs view
@@ -0,0 +1,257 @@+{-# LANGUAGE Trustworthy #-}+{-# LANGUAGE BangPatterns #-}+{-# LANGUAGE MagicHash #-}+{-# LANGUAGE OverloadedStrings #-}+{-# LANGUAGE UnboxedTuples #-}++-- | This module deals with escaping and sanitizing SQL templates.+module Database.PostgreSQL.Escape (+ fmtSql, quoteIdent, Id(..)+ , buildSql, buildSqlFromActions+ , buildAction, buildLiteral, buildByteA, buildIdent+ ) where++import Blaze.ByteString.Builder+import Blaze.ByteString.Builder.Char8 (fromChar)+import Blaze.ByteString.Builder.Internal+import qualified Data.ByteString as S+import qualified Data.ByteString.Internal as S+import qualified Data.ByteString.Unsafe as S+import Data.Monoid+import Data.String+import Database.PostgreSQL.Simple+import Database.PostgreSQL.Simple.ToField+import Database.PostgreSQL.Simple.ToRow+import Database.PostgreSQL.Simple.Types+import Foreign.Marshal.Alloc (mallocBytes)+import Foreign.Storable (pokeByteOff)+import Foreign.Ptr+import GHC.Prim (Addr#, and#, geAddr#, geWord#, int2Word#+ , minusAddr#, ord# , plusAddr#, readWord8OffAddr#+ , State# , uncheckedShiftRL#, word2Int#, writeWord8OffAddr#+ , Word#)+import GHC.Ptr (Ptr(Ptr))+import GHC.Types (Char(C#), Int(I#), IO(IO))+import GHC.Word (Word8(W8#))+import System.IO.Unsafe (unsafeDupablePerformIO)++c2b :: Char -> Word8+c2b (C# i) = W8# (int2Word# (ord# i))++c2b# :: Char -> Word#+c2b# (C# i) = int2Word# (ord# i)++fastFindIndex :: (Word# -> Bool) -> S.ByteString -> Maybe Int+{-# INLINE fastFindIndex #-}+fastFindIndex test bs =+ S.inlinePerformIO $ S.unsafeUseAsCStringLen bs $ \(Ptr bsp0, I# bsl0) -> do+ let bse = bsp0 `plusAddr#` bsl0+ check bsp = IO $ \rw -> case readWord8OffAddr# bsp 0# rw of+ (# rw1, w #) -> (# rw1, test w #)+ go bsp | bsp `geAddr#` bse = return Nothing+ | otherwise = do+ match <- check bsp+ if match+ then return $ Just $ I# (bsp `minusAddr#` bsp0)+ else go (bsp `plusAddr#` 1#)+ go bsp0++fastBreak :: (Word# -> Bool) -> S.ByteString -> (S.ByteString, S.ByteString)+{-# INLINE fastBreak #-}+fastBreak test bs+ | Just n <- fastFindIndex test bs = (S.unsafeTake n bs, S.unsafeDrop n bs)+ | otherwise = (bs, S.empty)++quoter :: S.ByteString -> S.ByteString -> (Word# -> Bool)+ -> (Word8 -> Builder) -> S.ByteString -> Builder+{-# INLINE quoter #-}+quoter start end escPred escFn bs0 =+ mconcat [copyByteString start, escaped bs0, copyByteString end]+ where escaped bs = case fastBreak escPred bs of+ (h, t) | S.null t -> fromByteString h+ | otherwise -> fromByteString h <>+ escFn (S.unsafeHead t) <>+ escaped (S.unsafeTail t)++-- | Quote an identifier using unicode quoting syntax. This is+-- necessary for identifiers containing a question mark, as otherwise+-- "PostgreSQL.Simple"'s naive formatting code will attempt to match+-- the question mark to a paremeter.+uBuildIdent :: S.ByteString -> Builder+uBuildIdent ident = quoter " U&\"" "\"" isSpecial esc ident+ where isSpecial 34## = True -- '"'+ isSpecial 63## = True -- '?'+ isSpecial 92## = True -- '\\'+ isSpecial _ = False+ esc c = copyByteString $ case () of+ _ | c == c2b '"' -> "\"\""+ | c == c2b '?' -> "\\003f"+ | c == c2b '\\' -> "\\\\"+ | otherwise -> error "uquoteIdent"++-- | Build a quoted identifier. Generally you will want to use+-- 'quoteIdent', and for repeated use it will be faster to use+-- @'fromByteString' . 'quoteIdent'@, but this internal function is+-- exposed in case it is useful.+buildIdent :: S.ByteString -> Builder+buildIdent ident+ | Just _ <- fastFindIndex isQuestionmark ident = uBuildIdent ident+ | otherwise = quoter "\"" "\"" isDQuote (const $ copyByteString "\"\"") ident+ where isQuestionmark 63## = True+ isQuestionmark 0## = error "quoteIdent: illegal NUL character"+ isQuestionmark _ = False+ isDQuote 34## = True+ isDQuote _ = False++-- | Quote an identifier such as a table or column name using+-- double-quote characters. Note this has nothing to do with quoting+-- /values/, which must be quoted using single quotes. (Anyway, all+-- values should be quoted by 'query' or 'fmtSql'.) This function+-- uses a unicode escape sequence to escape \'?\' characters, which+-- would otherwise be expanded by 'query', 'formatQuery', or 'fmtSql'.+--+-- >>> S8.putStrLn $ quoteIdent "hello \"world\"!"+-- "hello ""world""!"+-- >>> S8.putStrLn $ quoteIdent "hello \"world\"?"+-- U&"hello ""world""\003f"+--+-- Note that this quoting function is correct only if+-- @client_encoding@ is @SQL_ASCII@, @client_coding@ is @UTF8@, or the+-- identifier contains no multi-byte characters. For other coding+-- schemes, this function may erroneously duplicate bytes that look+-- like quote characters but are actually part of a multi-byte+-- character code. In such cases, maliciously crafted identifiers+-- will, even after quoting, allow injection of arbitrary SQL commands+-- to the server.+--+-- The upshot is that it is unwise to use this function on identifiers+-- provided by untrustworthy sources. Note this is true anyway,+-- regardless of @client_encoding@ setting, because certain \"system+-- column\" names (e.g., @oid@, @tableoid@, @xmin@, @cmin@, @xmax@,+-- @cmax@, @ctid@) are likely to produce unexpected results even when+-- properly quoted.+--+-- See 'Id' for a convenient way to include quoted identifiers in+-- parameter lists.+quoteIdent :: S.ByteString -> S.ByteString+quoteIdent = toByteString . buildIdent++-- | An identifier is a table or column name. When rendered into a+-- SQL query by 'fmtSql', it will be double-quoted, rather than+-- single-quoted. For example:+--+-- >>> fmtSql "select * from ? where name = ?" (Id "MyTable", "A Name")+-- "select * from \"MyTable\" where name = E'A Name'"+newtype Id = Id S.ByteString deriving Show+instance IsString Id where+ fromString = Id . fromString+instance ToField Id where+ toField (Id name) = Plain $ buildIdent name++hexNibblesPtr :: Ptr Word8+{-# NOINLINE hexNibblesPtr #-}+hexNibblesPtr = unsafeDupablePerformIO $ do+ ptr <- mallocBytes 16+ sequence_ $ zipWith (\o v -> pokeByteOff ptr o $ c2b v)+ [0..] (['0'..'9'] ++ ['a'..'f'])+ return ptr++-- | Bad things will happen if the argument is greater than 0xff.+uncheckedWriteNibbles# :: Addr# -> Word# -> State# d -> State# d+{-# INLINE uncheckedWriteNibbles# #-}+uncheckedWriteNibbles# p w rw0 =+ case (# word2Int# (w `uncheckedShiftRL#` 4# )+ , word2Int# (w `and#` 0xf## ) #) of { (# h, l #) ->+ case readWord8OffAddr# nibbles h rw0 of { (# rw1, hascii #) ->+ case writeWord8OffAddr# p 0# hascii rw1 of { rw2 ->+ case readWord8OffAddr# nibbles l rw2 of { (# rw3, lascii #) ->+ writeWord8OffAddr# p 1# lascii rw3 }}}}+ where !(Ptr nibbles) = hexNibblesPtr++hexCharEscBuilder :: Word8 -> Builder+{-# INLINE hexCharEscBuilder #-}+hexCharEscBuilder (W8# w) = fromWrite $ exactWrite 4 $ \(Ptr p) -> IO $ \rw0 ->+ (# uncheckedWriteNibbles# (p `plusAddr#` 2#) w+ (writeWord8OffAddr# p 1# (c2b# 'x')+ (writeWord8OffAddr# p 0# (c2b# '\\') rw0))+ , () #)++buildLiteral :: S.ByteString -> Builder+buildLiteral = quoter " E'" "'" isSpecial esc+ where isSpecial 39## = True -- '\''+ isSpecial 63## = True -- '?'+ isSpecial 92## = True -- '\\'+ isSpecial b = b `geWord#` 128##+ esc b | b == c2b '\'' = copyByteString "''"+ | b == c2b '\\' = copyByteString "\\\\"+ | otherwise = hexCharEscBuilder b+++copyByteToNibbles :: Addr# -> Addr# -> IO ()+{-# INLINE copyByteToNibbles #-}+copyByteToNibbles src dst = IO $ \rw0 ->+ case readWord8OffAddr# src 0# rw0 of+ (# rw1, w #) -> (# uncheckedWriteNibbles# dst w rw1, () #)++buildByteA :: S.ByteString -> Builder+buildByteA bs = equote $+ fromBuildStepCont $ \cont (BufRange (Ptr bb0) (Ptr be0)) ->+ S.unsafeUseAsCStringLen bs $ \(Ptr inptr0, I# inlen0) -> do+ let ine = plusAddr# inptr0 inlen0+ fill oute inp outp+ | inp `geAddr#` ine = cont (BufRange (Ptr outp) (Ptr oute))+ | plusAddr# outp 2# `geAddr#` oute = return $+ bufferFull (2 * (I# (ine `minusAddr#` inp)) + 1) (Ptr outp) $+ \(BufRange (Ptr bb) (Ptr be)) -> fill be inp bb+ | otherwise = do copyByteToNibbles inp outp+ fill oute (inp `plusAddr#` 1#) (outp `plusAddr#` 2#)+ fill be0 inptr0 bb0+ where equote b = mconcat [fromByteString " E'\\\\x", b, fromChar '\'']++++buildAction :: Action -> Builder+buildAction (Plain b) = b+buildAction (Escape bs) = buildLiteral bs+buildAction (EscapeByteA bs) = buildByteA bs+buildAction (Many bs) = mconcat $ map buildAction bs++-- | A lower-level function used by 'buildSql' and 'fmtSql'. You+-- probably don't need to call it directly.+buildSqlFromActions :: Query -> [Action] -> Builder+buildSqlFromActions (Query template) actions =+ intercatlate (split template) (map buildAction $ actions)+ where intercatlate (t:ts) (p:ps) = t <> p <> intercatlate ts ps+ intercatlate [t] [] = t+ intercatlate _ _ =+ error $ "buildSql: wrong number of parameters for " ++ show template+ split s = case S.breakByte (c2b '?') s of+ (h,t) | S.null t -> [fromByteString h]+ | otherwise -> fromByteString h : split (S.unsafeTail t)++-- | A builder version of 'fmtSql', possibly useful if you are about+-- to concatenate various individually formatted query fragments and+-- want to save the work of concatenating each individually.+buildSql :: (ToRow p) => Query -> p -> Builder+{-# INLINE buildSql #-}+buildSql q p = buildSqlFromActions q (toRow p)++-- | Take a SQL template containing \'?\' characters and a list of+-- paremeters whose length must match the number of \'?\' characters,+-- and format the result as an escaped 'S.ByteString' that can be used+-- as a query.+--+-- Like 'formatQuery', this function is naive about the placement of+-- \'?\' characters and will expand all of them, even ones within+-- quotes. To avoid this, you must use 'quoteIdent' on identifiers+-- containing question marks.+--+-- Also like 'formatQuery', \'?\' characters touching other \'?\'+-- characters or quoted strings may do the wrong thing, and end up+-- doubling a quote, so avoid substrings such as @\"??\"@ or+-- @\"?'string'\"@, as these could get expanded to, e.g.,+-- @\"\'param''string'\"@, which is a single string containing an+-- apostrophe, when you probably wanted two strings.+fmtSql :: (ToRow p) => Query -> p -> Query+{-# INLINE fmtSql #-}+fmtSql q p = Query $ toByteString $ buildSql q p
+ Database/PostgreSQL/Migrate.hs view
@@ -0,0 +1,154 @@+{-# LANGUAGE OverloadedStrings #-}++-- | Functions for creating and running database migrations. You should+-- probably be using the `pg_migrate` executable to run migrations, however+-- these functions are exposed for developers that want to integrate migrations+-- more tightly into their applications or utilities.++module Database.PostgreSQL.Migrate+ ( initializeDb+ , runMigrationsForDir+ , runRollbackForDir+ , dumpDb+ , defaultMigrationsDir+ , MigrationDetails(..)+ ) where++import Control.Monad+import Data.List+import Database.PostgreSQL.Simple hiding (connect)+import qualified Data.ByteString.Char8 as S8+import Database.PostgreSQL.Migrations+import System.Exit +import GHC.IO.Handle+import System.Cmd+import System.Process+import System.Directory+import System.FilePath+import System.Environment+import System.IO++-- | The default relative path containing migrations: \".\/dir\/migrations\"+defaultMigrationsDir :: FilePath+defaultMigrationsDir = "db" </> "migrations"++-- | Dumps the database schema to the given file handle.+--+-- This is a wrapper around the utility /pg_dump/ that comes with postgresql.+-- Therefore, /pg_dump/ must be installed on the system.+dumpDb :: Handle -> IO ExitCode+dumpDb outputFile = do+ dbUrl <- getEnvironment >>= return . maybe "" id . lookup "DATABASE_URL"+ (_, out, err, ph) <- runInteractiveProcess "pg_dump"+ [dbUrl, "--schema-only", "-O", "-x"] Nothing Nothing+ exitCode <- waitForProcess ph+ if exitCode /= ExitSuccess then do+ S8.hGetContents err >>= S8.hPut stderr+ else do+ raw <- S8.hGetContents out+ let clean = S8.concat $ intersperse "\n" $+ filter ((/= "--") . (S8.take 2)) $+ S8.lines raw+ S8.hPut outputFile clean+ return exitCode++-- | Initializes the database by creating a \"schema-migrations\" table.+-- This table must exist before running any migrations.+initializeDb :: IO ()+initializeDb = do+ conn <- connectEnv+ void $ execute_ conn "create table schema_migrations (version VARCHAR(28))"++-- | Runs all new migrations in a given directory and dumps the+-- resulting schema to a file \"schema.sql\" in the migrations+-- directory.+--+-- Determining which migrations to run is done by querying the database for the+-- largest version in the /schema_migrations/ table, and choosing all+-- migrations in the given directory with higher versions.+runMigrationsForDir :: Handle -- ^ Log output (probably stdout)+ -> FilePath -- ^ Path to directory containing migrations+ -> IO ExitCode+runMigrationsForDir logOut dir = do+ conn <- connectEnv+ res <- query_ conn+ "select version from schema_migrations order by version desc limit 1"+ let latestVersion = case res of+ [] -> ""+ (Only latest):_ -> latest+ migrations <- getDirectoryMigrations dir >>=+ return . (dropWhile (isVersion (<= latestVersion)))+ go migrations+ where go [] = withFile (dir </> ".." </> "schema.sql") WriteMode dumpDb+ go (mig@(MigrationDetails _ _ name):fs) = do+ hPutStrLn logOut $ "=== Running Migration " ++ name+ exitCode <- runMigration mig+ if exitCode == ExitSuccess then do+ hPutStrLn logOut "=== Success"+ go fs+ else do+ hPutStrLn logOut "=== Migration Failed!"+ return exitCode++-- | Run a migration. The returned exit code denotes the success or failure of+-- the migration.+runMigration :: MigrationDetails -> IO ExitCode+runMigration (MigrationDetails file version _) = do+ rawSystem "runghc"+ [file, "up", version, "--with-db-commit"]++runRollbackForDir :: FilePath -> IO ExitCode+runRollbackForDir dir = do+ conn <- connectEnv+ res <- query_ conn+ "select version from schema_migrations order by version desc limit 1"+ case res of+ [] -> do+ putStrLn "=== DB Fully Rolled Back!"+ return ExitSuccess+ (Only latest):_ -> do+ (Just (mig@(MigrationDetails _ _ name))) <-+ getDirectoryMigrations dir >>=+ return . (find (isVersion (== latest)))+ putStrLn $ "=== Running Rollback " ++ name+ exitCode <- runRollback mig+ if exitCode == ExitSuccess then do+ putStrLn "=== Success"+ withFile (dir </> ".." </> "schema.sql") WriteMode dumpDb+ else do+ putStrLn "=== Migration Failed!"+ return exitCode++-- | Run a migration. The returned exit code denotes the success or failure of+-- the migration.+runRollback :: MigrationDetails -> IO ExitCode+runRollback (MigrationDetails file version _) = do+ rawSystem "runghc"+ [file, "down", version, "--with-db-commit"]++data MigrationDetails = MigrationDetails { migrationPath :: FilePath+ , migrationVersion :: String+ , migrationName :: String }+ deriving (Show)++getDirectoryMigrations :: FilePath -> IO [MigrationDetails]+getDirectoryMigrations dir = do+ files0 <- getDirectoryContents dir+ let files = filter (('.' /=) . head) $ sort files0+ return $ map (splitFileVersionName dir) files++splitFileVersionName :: FilePath -> FilePath -> MigrationDetails+splitFileVersionName dir file = + let fileName = takeBaseName file+ parts = foldr (\chr (hd:result) ->+ if chr == '_' then+ "":hd:result+ else ((chr:hd):result))+ [""] fileName+ version = head parts+ name = concat $ intersperse "_" $ tail parts+ in MigrationDetails (dir </> file) version name++isVersion :: (String -> Bool) -> MigrationDetails -> Bool+isVersion cond (MigrationDetails _ v _) = cond v+
+ Database/PostgreSQL/Migrations.hs view
@@ -0,0 +1,415 @@+{-# LANGUAGE OverloadedStrings #-}++{- |+Functions to help with building database migrations.++Most users will want to create a database migration using @defaultMain@ as+follows,++>+> import Database.PostgreSQL.Migrations+>+> main = defaultMain up down+>+> up = migrate $ do+> create_table "posts"+> [ column "title" "VARCHAR(255) NOT NULL"+> , column "author_id" "integer references authors(id)"]+> +> down = migrate $ drop_table "posts"+>+-}+module Database.PostgreSQL.Migrations (+ -- * Utilities+ defaultMain+ , connectEnv+ , runSqlFile+ -- * DSL+ , Migration, migrate+ , column+ -- ** Adding+ , create_table+ , add_column+ , create_index+ , create_unique_index+ -- ** Removing+ , drop_table+ , drop_column+ , drop_index+ -- ** Modifying+ , rename_column+ , change_column+ -- ** Statements+ , create_table_stmt, add_column_stmt, create_index_stmt+ , drop_table_stmt, drop_column_stmt, drop_index_stmt+ , rename_column_stmt, change_column_stmt+ ) where++import Control.Monad+import Control.Monad.Reader+import qualified Data.ByteString as S+import qualified Data.ByteString.Char8 as S8+import Data.Int+import Data.Maybe+import Database.PostgreSQL.Simple hiding (connect)+import Database.PostgreSQL.Simple.Internal (exec)+import Database.PostgreSQL.Simple.Types+import System.Environment+import System.Exit++import Database.PostgreSQL.Escape++-- | Creates a PostgreSQL 'Connection' using the /DATABASE_URL/ environment+-- variable, if it exists. If it does, it should match the format:+--+-- @+-- postgresql:\/\/[[USERNAME\@PASSWORD]HOSTNAME[:PORT]]/[DBNAME]+-- @+--+-- If it is not present, the environment variables /PG_DBNAME/ /PG_HOST/ etc,+-- are used.+connectEnv :: IO Connection+connectEnv = do+ psqlStr <- getEnvironment >>=+ return . (fromMaybe "") . (lookup "DATABASE_URL")+ connectPostgreSQL $ S8.pack psqlStr++--+-- Migration Monad+--++type Migration = ReaderT Connection IO++migrate :: Migration a -> Connection -> IO ()+migrate = (void .) . runReaderT++executeQuery_ :: Query -> Migration Int64+executeQuery_ q = ask >>= \conn -> liftIO $ execute_ conn q++-- | Runs the SQL file at the given path, relative to the current working+-- directory.+runSqlFile :: FilePath -> Migration ()+runSqlFile sqlFile = void $ do+ conn <- ask+ liftIO $ do+ rawSql <- S.readFile sqlFile+ exec conn rawSql++-- | Returns a column defition by quoting the given name+column :: S8.ByteString -- ^ name+ -> S8.ByteString -- ^ type, definition, constraints+ -> S8.ByteString+column name def = S8.concat [quoteIdent name, " ", def]++-- | Creates a table. See 'column' for constructing the column list.+create_table :: S8.ByteString+ -- ^ Table name+ -> [S8.ByteString]+ -- ^ Column definitions+ -> Migration Int64+create_table = (executeQuery_ .) . create_table_stmt++-- | Returns a 'Query' that creates a table, for example:+--+-- @+-- create_table \"posts\"+-- [ column \"title\" \"VARCHAR(255) NOT NULL\"+-- , column \"body\" \"text\"]+-- @+create_table_stmt :: S8.ByteString+ -- ^ Table name+ -> [S8.ByteString]+ -- ^ Column definitions+ -> Query+create_table_stmt tableName colDefs = Query $ S8.concat $+ [ "create table "+ , quoteIdent tableName+ , " ("] ++ (S8.intercalate ", " colDefs):([");"])++-- | Drops a table+drop_table :: S8.ByteString -> Migration Int64+drop_table = executeQuery_ . drop_table_stmt++-- | Returns a 'Query' that drops a table+drop_table_stmt :: S8.ByteString -> Query+drop_table_stmt tableName = Query $ S8.concat+ [ "drop table ", quoteIdent tableName, ";"]++-- | Adds a column to the given table. For example,+--+-- @+-- add_column \"posts\" \"title\" \"VARCHAR(255)\"+-- @+--+-- adds a varchar column called \"title\" to the table \"posts\".+--+add_column :: S8.ByteString+ -- ^ Table name+ -> S8.ByteString+ -- ^ Column name+ -> S8.ByteString+ -- ^ Column definition+ -> Migration Int64+add_column = ((executeQuery_ .) .) . add_column_stmt++-- | Returns a 'Query' that adds a column to the given table. For example,+--+-- @+-- add_column \"posts\" \"title\" \"VARCHAR(255)\"+-- @+--+-- Returns the query+--+-- @+-- ALTER TABLE \"posts\" add \"title\" VARCHAR(255);+-- @+add_column_stmt :: S8.ByteString+ -- ^ Table name+ -> S8.ByteString+ -- ^ Column name+ -> S8.ByteString+ -- ^ Column definition+ -> Query+add_column_stmt tableName colName colDef = Query $ S8.concat+ [ "alter table ", quoteIdent tableName, " add ", column colName colDef, ";"]++-- | Drops a column from the given table. For example,+--+-- @+-- drop_column \"posts\" \"title\"+-- @+--+-- drops the column \"title\" from the \"posts\" table.+drop_column :: S8.ByteString+ -- ^ Table name+ -> S8.ByteString+ -- ^ Column name+ -> Migration Int64+drop_column = (executeQuery_ .) . drop_column_stmt++-- | Returns a 'Query' that drops a column from the given table. For example,+--+-- @+-- drop_column \"posts\" \"title\"+-- @+--+-- Returns the query+--+-- @+-- ALTER TABLE \"posts\" add \"title\";+-- @+drop_column_stmt :: S8.ByteString+ -- ^ Table name+ -> S8.ByteString+ -- ^ Column name+ -> Query+drop_column_stmt tableName colName = Query $ S8.concat+ ["alter table ", quoteIdent tableName, " drop ", quoteIdent colName, ";"]++-- | Renames a column in the given table. For example,+--+-- @+-- rename_column \"posts\" \"title\" \"name\"+-- @+--+-- renames the column \"title\" in the \"posts\" table to \"name\".+rename_column :: S8.ByteString+ -- ^ Table name+ -> S8.ByteString+ -- ^ Old column name+ -> S8.ByteString+ -- ^ New column name+ -> Migration Int64+rename_column = ((executeQuery_ .) .) . rename_column_stmt++-- | Returns a 'Query' that renames a column in the given table. For example,+--+-- @+-- rename_column \"posts\" \"title\" \"name\"+-- @+--+-- Returns the query+--+-- @+-- ALTER TABLE \"posts\" RENAME \"title\" TO \"name\";+-- @+rename_column_stmt :: S8.ByteString+ -- ^ Table name+ -> S8.ByteString+ -- ^ Old column name+ -> S8.ByteString+ -- ^ New column name+ -> Query+rename_column_stmt tableName colName colNameNew = Query $ S8.concat+ [ "alter table ", quoteIdent tableName, " rename "+ , quoteIdent colName, " to ", quoteIdent colNameNew, ";"]++-- | Alters a column in the given table. For example,+--+-- @+-- change_column \"posts\" \"title\" \"DROP DEFAULT\"+-- @+--+-- drops the default constraint for the \"title\" column in the \"posts\"+-- table.+change_column :: S8.ByteString+ -- ^ Table name+ -> S8.ByteString+ -- ^ Column name+ -> S8.ByteString+ -- ^ Action+ -> Migration Int64+change_column = ((executeQuery_ .) .) . change_column_stmt++-- | Returns a 'Query' that alters a column in the given table. For example,+--+-- @+-- change_column \"posts\" \"title\" \"DROP DEFAULT\"+-- @+--+-- Returns the query+--+-- @+-- ALTER TABLE \"posts\" ALTER \"title\" DROP DEFAULT;+-- @+change_column_stmt :: S8.ByteString+ -- ^ Table name+ -> S8.ByteString+ -- ^ Column name+ -> S8.ByteString+ -- ^ Action+ -> Query+change_column_stmt tableName colName action = Query $ S8.concat+ [ "alter table ", quoteIdent tableName, " alter "+ , quoteIdent colName, " ", action, ";"]++data CmdArgs = CmdArgs { cmd :: String+ , cmdVersion :: String+ , cmdCommit :: Bool }++-- | Creates an index for efficient lookup.+create_index :: S8.ByteString+ -- ^ Index name+ -> S8.ByteString+ -- ^ Table name+ -> [S8.ByteString]+ -- ^ Column names+ -> Migration Int64+create_index = ((executeQuery_ .) .) . (create_index_stmt False)++-- | Creates a unique index for efficient lookup.+create_unique_index :: S8.ByteString+ -- ^ Index name+ -> S8.ByteString+ -- ^ Table name+ -> [S8.ByteString]+ -- ^ Column names+ -> Migration Int64+create_unique_index = ((executeQuery_ .) .) . (create_index_stmt True)++-- | Returns a 'Query' that creates an index for the given columns on the given+-- table. For example,+--+-- @+-- create_index_stmt \"post_owner_index\" \"posts\" \"owner\"+-- @+--+-- Returns the query+--+-- @+-- CREATE INDEX \"post_owner_index\" ON \"posts\" (\"owner\")+-- @+create_index_stmt :: Bool + -- ^ Unique index?+ -> S8.ByteString+ -- ^ Index name+ -> S8.ByteString+ -- ^ Table name+ -> [S8.ByteString]+ -- ^ Column names+ -> Query+create_index_stmt unq indexName tableName colNames = Query $ S8.concat+ [ "create", unique, " index ", quoteIdent indexName, " on "+ , quoteIdent tableName, " (", cols, ")", ";" ]+ where cols = S8.intercalate ", " $ map quoteIdent colNames+ unique = if unq then " unique" else ""++-- | Drops an index.+drop_index :: S8.ByteString+ -- ^ Index name+ -> Migration Int64+drop_index = executeQuery_ . drop_index_stmt++-- | Returns a 'Query' that drops an index.+--+-- @+-- drop_index_stmt \"post_owner_index\"+-- @+--+-- Returns the query+--+-- @+-- DROP INDEX \"post_owner_index\"+-- @+drop_index_stmt :: S8.ByteString+ -- ^ Index name+ -> Query+drop_index_stmt indexName = Query $ S8.concat+ [ "drop index ", quoteIdent indexName, ";" ]++parseCmdArgs :: [String] -> Maybe CmdArgs+parseCmdArgs args = do+ mycmd <- listToMaybe args+ let args0 = tail args+ myversion <- listToMaybe args0+ return $ go (CmdArgs mycmd myversion False) $ tail args0+ where go res [] = res+ go res (arg:as) =+ let newRes = case arg of+ "--with-db-commit" -> res { cmdCommit = True }+ _ -> res+ in go newRes as++defaultMain :: (Connection -> IO ()) -- ^ Migration function+ -> (Connection -> IO ()) -- ^ Rollback function+ -> IO ()+defaultMain up down = do+ (Just cmdArgs) <- getArgs >>= return . parseCmdArgs+ case cmd cmdArgs of+ "up" -> do+ conn <- connectEnv+ res <- query_ conn+ "select version from schema_migrations order by version desc limit 1"+ let currentVersion = case res of+ [] -> ""+ (Only v):_ -> v+ let version = cmdVersion cmdArgs+ if currentVersion < version then do+ begin conn+ up conn+ void $ execute conn "insert into schema_migrations values(?)"+ (Only version)+ if cmdCommit cmdArgs then+ commit conn+ else rollback conn+ else exitWith $ ExitFailure 1+ "down" -> do+ conn <- connectEnv+ res <- query_ conn+ "select version from schema_migrations order by version desc limit 1"+ let currentVersion = case res of+ [] -> ""+ (Only v):_ -> v+ let version = cmdVersion cmdArgs+ if currentVersion == version then do+ begin conn+ down conn+ void $ execute conn "delete from schema_migrations where version = ?"+ (Only version)+ if cmdCommit cmdArgs then+ commit conn+ else rollback conn+ else+ exitWith $ ExitFailure 1+ _ -> exitWith $ ExitFailure 1+
+ Database/PostgreSQL/ORM.hs view
@@ -0,0 +1,29 @@++module Database.PostgreSQL.ORM (+ -- * The Model class and related types+ Model(modelInfo, modelValid), ModelInfo(..)+ , defaultModelInfo, underscoreModelInfo+ , DBKey(..), DBRef, DBRefUnique, mkDBRef, primaryKey+ , (:.), As(..), RowAlias(..), fromAs+ -- ** Single-row operations+ , findRow, findAll, save, trySave, destroy, destroyByRef+ -- * Abstracted select queries+ , DBSelect(..), modelDBSelect, dbSelectParams, dbSelect+ , addWhere_, addWhere, setOrderBy, setLimit, setOffset+ -- * Associations between models+ , Association, assocSelect, assocProject, assocWhere, findAssoc+ -- ** Parent-child associations+ , GDBRefInfo(..), DBRefInfo, defaultDBRefInfo, dbrefAssocs, has, belongsTo+ -- ** Join table associations+ , JoinTable(..), defaultJoinTable, jtAssocs, jtAdd, jtRemove, jtRemoveByRef+ -- ** Chaining associations+ , nestAssoc, chainAssoc+ -- ** Validations+ , InvalidError(..), ValidationError(..), validate, validateNotEmpty+ ) where++import Database.PostgreSQL.ORM.Model+import Database.PostgreSQL.ORM.DBSelect+import Database.PostgreSQL.ORM.Association+import Database.PostgreSQL.ORM.Validations+import Database.PostgreSQL.Simple ((:.))
+ Database/PostgreSQL/ORM/Association.hs view
@@ -0,0 +1,540 @@+{-# LANGUAGE FlexibleContexts #-}+{-# LANGUAGE FlexibleInstances #-}+{-# LANGUAGE MultiParamTypeClasses #-}+{-# LANGUAGE OverloadedStrings #-}+{-# LANGUAGE ScopedTypeVariables #-}+{-# LANGUAGE TypeOperators #-}++module Database.PostgreSQL.ORM.Association (+ Association(..), assocProject, assocWhere, findAssoc+ -- * Associations based on parent-child relationships+ , GDBRefInfo(..), DBRefInfo, defaultDBRefInfo, dbrefAssocs, has, belongsTo+ -- * Join table Associations+ , JoinTable(..), defaultJoinTable, jtAssocs, joinTable+ -- ** Operations on join tables+ , jtAdd, jtRemove, jtRemoveByRef+ -- ** Semi-internal join table functions+ , jtAddStatement, jtRemoveStatement, jtParam+ , jtFlip, jtAssoc+ -- * Nested and chained associations+ , nestAssoc, chainAssoc+ ) where++import Control.Applicative+import qualified Data.ByteString as S+import qualified Data.ByteString.Char8 as S8+import Data.List+import Data.Monoid+import Database.PostgreSQL.Simple+import Database.PostgreSQL.Simple.ToField+import Database.PostgreSQL.Simple.Types++import Data.GetField+import Database.PostgreSQL.Escape+import Database.PostgreSQL.ORM.DBSelect+import Database.PostgreSQL.ORM.Model+++-- | A data structure representing a relationship between a model @a@+-- and a model @b@. At a high level, an @Association a b@ tells you+-- how to find rows of type @b@ given rows of type @a@. More+-- concretely, this boils down to being able to make two types of+-- query.+--+-- * You want to look up a bunch of @(a ':.' b)@s, filtering using+-- predicates on both @a@ and @b@ (e.g., get a list of recent posts+-- and their authors). For this purpose, you can use 'assocSelect',+-- which allows you to 'addWhere' predicates mentioning columns in+-- both @a@ and @b@.+--+-- * You already have an instance of type @a@, and want to find all+-- the @b@s associated with it. For that you use either 'assocWhere'+-- or 'findAssoc' (which internally access fields 'assocSelectOnlyB',+-- 'assocWhereQuery', and 'assocWhereParam'). This type of query is+-- strictly less general than the first one, but can be formulated in+-- a more efficient way by extracting values directly from a concrete+-- instance of @a@ without needing to touch table @a@ in the+-- database.+-- +-- Note that an @Association@ is asymmetric. It tells you how to get+-- @b@s from @a@s, but not vice versa. In practice, there will almost+-- always be an association in the other direction, too. Functions+-- such as 'dbrefAssocs' and 'jtAssocs' therefore create an+-- @Association@ and its inverse simultaneously, returning them as a+-- pair.+data Association a b = Association {+ assocSelect :: !(DBSelect (a :. b))+ -- ^ General select returning all instances of @a@ and @b@ that+ -- match according to the association.+ , assocSelectOnlyB :: !(DBSelect b)+ -- ^ The right-hand side of the 'assocSelect' query. This query+ -- makes no mention of type @a@ (but can be combined with the next+ -- two fields to form an optimized query). You probably never+ -- want to use this directly, and should instead use either+ -- 'findAssoc' or 'assocWhere'. Also note this is not useful for+ -- selecting all the @b@s in the relation; for that you should use+ -- 'assocProject'.+ , assocWhereQuery :: !Query+ -- ^ A @WHERE@ clause to find all the 'b's associated with a+ -- particular @a@. This can often be done more efficiently than+ -- through 'assocSelect'. The clause contains @\'?\'@ characters+ -- which should be filled in by 'assocWhereParam'.+ , assocWhereParam :: !(a -> [Action])+ -- ^ The query parameters for the query returned by+ -- 'assocWhereQuery'.+ }++instance Show (Association a b) where+ show assoc =+ "Association { assocSelect = " ++ show (assocSelect assoc) +++ ", assocSelectOnlyB = " ++ show (assocSelectOnlyB assoc) +++ ", assocWhereQuery = " ++ S8.unpack (fromQuery $ assocWhereQuery assoc) +++ " }"++-- | A projection of 'assocSelect', extracting only the fields of+-- model @b@. Note that this query touches table @a@ even if it does+-- not return results from @a@. Hence, you can use 'addWhere' to add+-- predicates on both @a@ and @b@. (Note the contrast to+-- 'assocSelectOnlyB', which does not touch table @a@ at all, and+-- hence in the case of an @INNER JOIN@ might return rows of @b@ that+-- should not be part of the association. 'assocSelectOnlyB' is+-- intended for use only in conjunction with 'assocWhereQuery'.)+assocProject :: (Model b) => Association a b -> DBSelect b+assocProject = dbProject . assocSelect++-- | Returns a 'DBSelect' for all @b@s associated with a particular+-- @a@.+assocWhere :: (Model b) => Association a b -> a -> DBSelect b+assocWhere ab a = addWhere (assocWhereQuery ab) (assocWhereParam ab a)+ (assocSelectOnlyB ab)++-- | Follow an association to return all of the @b@s associated+-- with a particular @a@. The behavior is similar to:+--+-- > findAssoc' ab c a = dbSelect c $ assocWhere ab a+--+-- But if the first argument is a static association, this function+-- may be marginally faster because it pre-renders most of the query.+findAssoc :: (Model b) => Association a b -> Connection -> a -> IO [b]+{-# INLINE findAssoc #-}+findAssoc assoc = \c a ->+ map lookupRow <$> query c q (assocWhereParam assoc a)+ where {-# NOINLINE q #-}+ q = renderDBSelect $+ addWhere_ (assocWhereQuery assoc) $ assocSelectOnlyB assoc++-- | Combine two associations into one.+nestAssoc :: (Model a, Model b) =>+ Association a b -> Association b c -> Association a (b :. c)+nestAssoc ab bc = ab { assocSelect = dbNest (assocSelect ab) (assocSelect bc)+ , assocSelectOnlyB = assocSelect bc }++-- | Combine two associations into one, and project away the middle+-- type. (The middle type can still be mentioned in @WHERE@ clauses.)+--+-- An example:+--+-- > data Author = Author {+-- > authorId :: DBKey+-- > } deriving (Show, Generic)+-- > instance Model Author where modelInfo = underscoreModelInfo "author"+-- > +-- > data Post = Post {+-- > postId :: DBKey+-- > , postAuthorId :: DBRef Author+-- > } deriving (Show, Generic)+-- > instance Model Post where modelInfo = underscoreModelInfo "post"+-- > +-- > data Comment = Comment {+-- > commentId :: DBKey+-- > , commentPostId :: DBRef Post+-- > } deriving (Show, Generic)+-- > instance Model Comment where modelInfo = underscoreModelInfo "comment"+-- > +-- > author_posts :: Association Author Post+-- > post_author :: Association Post Author+-- > (post_author, author_posts) = dbrefAssocs defaultDBRefInfo+-- > +-- > -- Could equally well use dbrefAssocs as above+-- > post_comments :: Association Post Comment+-- > post_comments = has+-- >+-- > comment_post :: Association Comment Post+-- > comment_post = belongsTo+-- > +-- > comment_author :: Association Comment Author+-- > comment_author = chainAssoc comment_post post_author+-- > +-- > author_comments :: Association Author Comment+-- > author_comments = chainAssoc author_posts post_comments+chainAssoc :: (Model a, Model b, Model c) =>+ Association a b -> Association b c -> Association a c+chainAssoc ab bc = ab { assocSelect = dbChain (assocSelect ab) (assocSelect bc)+ , assocSelectOnlyB = dbProject $ assocSelect bc }+++-- | A common type of association is when one model contains a 'DBRef'+-- or 'DBRefUnique' pointing to another model. In this case, the+-- model containing the 'DBRef' is known as the /child/, and the+-- referenced model is known as the /parent/.+--+-- Two pieces of information are required to describe a parent-child+-- relationship: First, the field selector that extracts the Haskell+-- 'DBRef' from the haskell type @child@, and second the name of the+-- database column that stores this 'DBRef' field.+--+-- For example, consider the following:+--+-- > data Author = Author {+-- > authorId :: DBKey+-- > } deriving (Show, Generic)+-- > instance Model Author+-- > +-- > data Post = Post {+-- > postId :: DBKey+-- > , postAuthorId :: DBRef Author+-- > } deriving (Show, Generic)+-- > instance Model Post+-- >+-- > post_author_refinfo :: DBRefInfo Post Author+-- > post_author_refinfo = DBRefInfo {+-- > dbrefSelector = postAuthorId+-- > , dbrefQColumn = "\"post\".\"postAuthorId\""+-- > }+--+-- Note that the parent-child relationship described by a @GDBRefInfo@+-- is asymmetric, but bidirectional. When a @'DBRefInfo' child+-- parent@ exists, the schema should generally /not/ permit the+-- existence of a valid @'DBRefInfo' parent child@ structure.+-- However, the 'dbrefAssocs' function generates 'Association's in+-- both directions from a single 'DBRefInfo'.+--+-- Constructing such parent-child 'Association's requires knowing how+-- to extract primary keys from the @parent@ type as well as the name+-- of the column storing primary keys in @parent@. Fortunately, this+-- information is already available from the 'Model' class, and thus+-- does not need to be in the @GDBRefInfo@. (Most functions on+-- @GDBRefInfo@s require @parent@ and @child@ to be instances of+-- 'Model'.)+--+-- When your 'Model's are instances of 'Generic' (which will usually+-- be the case), a 'DBRefInfo' structure can be computed automatically+-- by 'defaultDBRefInfo'. This is the recommended way to produce a+-- @GDBRefInfo@. (Alternatively, see 'has' and 'belongsTo' to make+-- use of an entirely implicit @DBRefInfo@.)+data GDBRefInfo reftype child parent = DBRefInfo {+ dbrefSelector :: !(child -> GDBRef reftype parent)+ -- ^ Field selector returning a reference.+ , dbrefQColumn :: !S.ByteString+ -- ^ Literal SQL for the database column storing the reference.+ -- This should be double-quoted and table-qualified, in case the+ -- column name is a reserved keyword, contains capital letters, or+ -- conflicts with the name of a column in the joined table. An+ -- example would be:+ --+ -- > dbrefQColumn = "\"table_name\".\"column_name\""+ }++instance Show (GDBRefInfo rt c p) where+ show ri = "DBRefInfo ? " ++ show (dbrefQColumn ri)++-- | @DBRefInfo@ is a type alias for the common case that the+-- reference in a 'GDBRefInfo' is a 'DBRef' (as opposed to a+-- 'DBRefUnique'). The functions in this library do not care what+-- type of reference is used. The type is generalized to 'GDBRefInfo'+-- just to make it easier to assign a selector to 'dbrefSelector' when+-- the selector returns a 'DBRefUnique'. Note, however, that+-- 'defaultDBRefInfo' returns a 'DBRefInfo' regardless of the flavor+-- of reference actually encountered.+type DBRefInfo = GDBRefInfo NormalRef++data ExtractRef a = ExtractRef deriving (Show)+instance Extractor ExtractRef (GDBRef rt a) (DBRef a) THasOne where+ extract _ (DBRef k) = THasOne $ DBRef k+instance Extractor ExtractRef (GDBRef rt a) (DBRef (As alias a)) THasOne where+ extract _ (DBRef k) = THasOne $ DBRef k+instance Extractor ExtractRef (Maybe (GDBRef rt a)) (DBRef a) THasOne where+ extract _ (Just (DBRef k)) = THasOne $ DBRef k+ extract _ _ = error "Maybe DBRef is Nothing"+instance Extractor ExtractRef (Maybe (GDBRef rt a)) (DBRef (As alias a))+ THasOne where+ extract _ (Just (DBRef k)) = THasOne $ DBRef k+ extract _ _ = error "Maybe DBRef is Nothing"++-- | Creates a 'DBRefInfo' from a model @child@ that references+-- @parent@. For this to work, the @child@ type must be an instance+-- of 'Generic' and must contain exactly one field of the any of the+-- following types:+--+-- 1. @'GDBRef' rt parent@, which matches both @'DBRef' parent@ and+-- @'DBRefUnique' parent@.+--+-- 2. @Maybe ('GDBRef' rt parent)@, for cases where the reference+-- might be @NULL@. Note, however, that an exception will be thrown+-- if you call 'findAssoc' on a child whose reference is 'Nothing'.+--+-- A special case arises when a Model contains a 'DBRef' to itself.+-- If you just wish to find parents and children given an existing+-- structure (i.e., 'findAssoc'), it is okay to declare an+-- @'Association' MyType MyType@. However, in this case attempts to+-- use 'assocSelect' will then fail. To work around this problem, the+-- parent must use a row alias.+--+-- Note that currently /aliasing the child will not work/, since the+-- 'As' data structure will not contain a 'DBRef' field, only the+-- contents of the 'As' data structure. An example of doing this+-- correctly (using 'has' and 'belongsTo', both of which wrap+-- @defaultDBRefInfo@):+--+-- > data Bar = Bar {+-- > barId :: !DBKey+-- > , barName :: !String+-- > , barParent :: !(Maybe (DBRef Bar))+-- > } deriving (Show, Generic)+-- > instance Model Bar where modelInfo = underscoreModelInfo "bar"+-- > +-- > data ParentBar = ParentBar+-- > instance RowAlias ParentBar where rowAliasName _ = "parent_bar"+-- > +-- > toParent :: Association Bar (As ParentBar Bar)+-- > toParent = belongsTo+-- > +-- > toChild :: Association (As ParentBar Bar) Bar+-- > toChild = has+defaultDBRefInfo :: forall child parent.+ (Model child, Model parent+ , GetField ExtractRef child (DBRef parent)) =>+ DBRefInfo child parent+defaultDBRefInfo = ri+ where extractor = (const ExtractRef :: g p -> ExtractRef (DBRef p)) ri+ child = undefined :: child+ childids = modelIdentifiers :: ModelIdentifiers child+ ri = DBRefInfo {+ dbrefSelector = getFieldVal extractor+ , dbrefQColumn = modelQColumns childids !! getFieldPos extractor child+ }++-- | Generate both the child-parent and parent-child 'Association's+-- implied by a 'GDBRefInfo'.+dbrefAssocs :: forall child parent rt.+ (Model child, Model parent) =>+ GDBRefInfo rt child parent+ -> (Association child parent, Association parent child)+dbrefAssocs ri = (c_p, p_c)+ where idp = modelIdentifiers :: ModelIdentifiers parent+ on = Query $ "ON " <> modelQPrimaryColumn idp+ <> " = " <> dbrefQColumn ri+ c_p = Association {+ assocSelect = dbJoinModels "JOIN" on+ , assocSelectOnlyB = modelDBSelect+ , assocWhereQuery = Query $ modelQPrimaryColumn idp <> " = ?"+ , assocWhereParam = \child -> [toField $ dbrefSelector ri child]+ }+ p_c = Association {+ assocSelect = dbJoinModels "JOIN" on+ , assocSelectOnlyB = modelDBSelect+ , assocWhereQuery = Query $ dbrefQColumn ri <> " = ?"+ , assocWhereParam = \parent -> [toField $ primaryKey parent]+ }+++-- | Short for+--+-- > snd $ dbrefAssocs defaultDBRefInfo+--+-- Note the inverse 'Association' is given by 'belongsTo'. For+-- example, given the @Author@ and @Post@ models described in the+-- documentation for 'GDBRefInfo', in which each @Post@ references an+-- @Author@, you might say:+--+-- > author_post :: Association Author Post+-- > author_post = has+-- >+-- > post_author :: Association Post Author+-- > post_author = belongsTo+has :: (Model child, Model parent, GetField ExtractRef child (DBRef parent)) =>+ Association parent child+has = snd $ dbrefAssocs defaultDBRefInfo++-- | The inverse of 'has'. Short for+--+-- > fst $ dbrefAssocs defaultDBRefInfo+--+-- See an example at 'has'.+belongsTo :: (Model child, Model parent+ , GetField ExtractRef child (DBRef parent)) =>+ Association child parent+belongsTo = fst $ dbrefAssocs defaultDBRefInfo++-- | A data structure representing a dedicated join table in the+-- database. A join table differs from a model in that rows do not+-- have primary keys. Hence, model operations do not apply.+-- Nonetheless a join table conveys information about a relationship+-- between models.+--+-- Note that all names in a @JoinTable@ should be unquoted.+data JoinTable a b = JoinTable {+ jtTable :: !S.ByteString+ -- ^ Name of the join table in the database. (Not quoted.)+ , jtColumnA :: !S.ByteString+ -- ^ Name of the column in table 'jtTable' that contains a 'DBRef'+ -- to model @a@. (Not quoted or table-qualified.)+ , jtColumnB :: !S.ByteString+ -- ^ Like 'jtColumnA' for model @b@.+ } deriving (Show)++-- | The default join table has the following fields:+--+-- * 'jtName' is the name of the two models (in alphabetical order),+-- separated by an @\'_\'@ character.+--+-- * 'jtColumnA' is the name of model @a@, an @\'_\'@ character, and+-- the name of the primary key column in table @a@.+--+-- * 'jtColumnB' is the name of model @b@, an @\'_\'@ character, and+-- the name of the primary key column in table @b@.+--+-- Note that 'defaultJoinTable' cannot create a default join table for+-- joining a model to itself, as following these rules the two columns+-- would have the same name. If you wish to join a table to itself,+-- you have two options: First, you can define the join table and+-- assign the column names manually. This will permit you to call+-- 'findAssoc', but you still will not be able to use 'assocSelect'+-- for more complex queries, since SQL does not permit joins between+-- two tables with the same name. The second option is to give one of+-- the sides of the join table a row alias with 'As'. For example:+--+-- > data ParentBar = ParentBar+-- > instance RowAlias ParentBar where rowAliasName _ = "parent_bar"+-- > +-- > selfJoinTable :: JoinTable Bar (As ParentBar Bar)+-- > selfJoinTable = defaultJoinTable+-- > +-- > selfJoin :: Association Bar (As ParentBar Bar)+-- > otherSelfJoin :: Association (As ParentBar Bar) Bar+-- > (selfJoin, otherSelfJoin) = jtAssocs selfJoinTable+defaultJoinTable :: forall a b. (Model a, Model b) => JoinTable a b+defaultJoinTable+ | colA == colB = error "defaultJoinTable has default for self joins"+ | otherwise = jti+ where a = modelInfo :: ModelInfo a+ b = modelInfo :: ModelInfo b+ colA = S.intercalate "_"+ [modelTable a, modelColumns a !! modelPrimaryColumn a]+ colB = S.intercalate "_"+ [modelTable b, modelColumns b !! modelPrimaryColumn b]+ jti = JoinTable {+ jtTable = S.intercalate "_" $ sort [modelTable a, modelTable b]+ , jtColumnA = colA+ , jtColumnB = colB+ }++jtQTable :: JoinTable a b -> S.ByteString+jtQTable = quoteIdent . jtTable++jtQColumnA :: JoinTable a b -> S.ByteString+jtQColumnA jt = S.concat [ jtQTable jt, ".", quoteIdent $ jtColumnA jt]++jtQColumnB :: JoinTable a b -> S.ByteString+jtQColumnB jt = S.concat [ jtQTable jt, ".", quoteIdent $ jtColumnB jt]++-- | Flip a join table. This doesn't change the name of the table+-- (since the same join table is used in both directions, and the+-- default join table name glues together the two model names in+-- alphabetical order anyway).+jtFlip :: JoinTable a b -> JoinTable b a+jtFlip jt = jt { jtColumnA = jtColumnB jt , jtColumnB = jtColumnA jt }++-- | A SQL statement suitable for adding a pair to a join table. Note+-- that the statement takes two parameters (i.e., contains two @\'?\'@+-- characters) corresponding to the primary keys of the two models+-- being associated. These parameters can be supplied by 'jtParam'.+jtAddStatement :: JoinTable a b -> Query+jtAddStatement jt = Query $ S.concat [+ "INSERT INTO ", jtQTable jt, " ("+ , quoteIdent $ jtColumnA jt, ", ", quoteIdent $ jtColumnB jt+ , ") VALUES (?, ?) EXCEPT SELECT "+ , jtQColumnA jt, ", ", jtQColumnB jt, " FROM ", quoteIdent $ jtTable jt+ ]++-- | Add an association between two models to a join table. Returns+-- 'True' if the association was not already there.+jtAdd :: (Model a, Model b) => JoinTable a b -> Connection -> a -> b -> IO Bool+{-# INLINE jtAdd #-}+jtAdd jt = \c a b -> (/= 0) <$> execute c q (jtParam jt a b)+ where {-# NOINLINE q #-}+ q = jtAddStatement jt++-- | A SQL statement for removing a pair from a join table. Like+-- 'jtAddStatement', the query is parameterized by two primary keys.+jtRemoveStatement :: JoinTable a b -> Query+jtRemoveStatement jt = Query $ S.concat [+ "DELETE FROM ", quoteIdent $ jtTable jt, " WHERE "+ , jtQColumnA jt, " = ? AND ", jtQColumnB jt, " = ?"+ ]++-- | Remove an association from a join table. Returns 'True' if the+-- association was previously there.+jtRemove :: (Model a, Model b) =>+ JoinTable a b -> Connection -> a -> b -> IO Bool+{-# INLINE jtRemove #-}+jtRemove jt = \c a b -> (/= 0) <$> execute c q (jtParam jt a b)+ where {-# NOINLINE q #-}+ q = jtRemoveStatement jt++-- | Remove an assocation from a join table when you don't have the+-- target instances of the two models handy, but do have references.+jtRemoveByRef :: (Model a, Model b) => JoinTable a b+ -> Connection -> GDBRef rt a -> GDBRef rt b -> IO Bool+{-# INLINE jtRemoveByRef #-}+jtRemoveByRef jt = \c a b -> (/= 0) <$> execute c q (a, b)+ where {-# NOINLINE q #-}+ q = jtRemoveStatement jt++-- | Generate parameters for 'jtAddStatement' and 'jtRemoveStatement'.+-- The returned list is suitable for use as a 'ToRow' instance. For+-- example:+--+-- > execute conn (jtAddStatement my_join_table) (jtParam a b)+jtParam :: (Model a, Model b) => JoinTable a b -> a -> b -> [Action]+jtParam _ a b = [toField $ primaryKey a, toField $ primaryKey b]++-- | Generate a one-way association from a 'JoinTable'. Use+-- 'jtAssocs' instead.+jtAssoc :: forall a b. (Model a, Model b) => JoinTable a b -> Association a b+jtAssoc jt = Association {+ assocSelect = dbJoin modelDBSelect "JOIN" onlyB $ Query $ S.concat [+ "ON ", priA, " = ", jtQColumnA jt]+ , assocSelectOnlyB = onlyB+ , assocWhereQuery = Query $ jtQColumnA jt <> " = ?"+ , assocWhereParam = \a -> [toField $ primaryKey a]+ }+ where priA = modelQPrimaryColumn (modelIdentifiers :: ModelIdentifiers a)+ priB = modelQPrimaryColumn (modelIdentifiers :: ModelIdentifiers b)+ selB = modelDBSelect :: DBSelect b+ fromB = FromJoin+ (FromModel (Query $ jtQTable jt) (jtQTable jt))+ "JOIN" (selFrom selB)+ (Query $ S.concat ["ON ", jtQColumnB jt, " = ", priB])+ (jtQTable jt <> "->B")+ onlyB = selB { selFrom = fromB }++-- | Generate the two associations implied by a 'JoinTable'.+jtAssocs :: (Model a, Model b) =>+ JoinTable a b -> (Association a b, Association b a)+jtAssocs jt = (jtAssoc jt, jtAssoc $ jtFlip jt)++-- | Generate a one-way association based on the default join table+-- naming scheme described at 'defaultJoinTable'. Defined as:+--+-- > joinTable = jtAssoc defaultJoinTable+--+-- For example:+--+-- > aToB :: Association A B+-- > aToB = joinTable+-- >+-- > bToA :: Association B A+-- > bToA = joinTable+joinTable :: (Model a, Model b) => Association a b+joinTable = jtAssoc defaultJoinTable
+ Database/PostgreSQL/ORM/CreateTable.hs view
@@ -0,0 +1,104 @@+{-# LANGUAGE FlexibleContexts #-}+{-# LANGUAGE ScopedTypeVariables #-}+{-# LANGUAGE TypeOperators #-}+{-# LANGUAGE OverloadedStrings #-}++-- | Functions for creating a table from a model. These are mostly+-- useful in development, for very rigid applications, or to compare+-- what would be created against what is actually in the database. In+-- practice, production settings should create and update tables using+-- migrations.+--+-- Note that often it is more interesting to see what would be created+-- than to create an actual table. For that reason, functions+-- creating the statements are exposed.+module Database.PostgreSQL.ORM.CreateTable (+ modelCreateStatement, modelCreate, GDefTypes(..)+ , jtCreateStatement, jtCreate+ ) where++import qualified Data.ByteString as S+import qualified Data.ByteString.Char8 as S8+import Data.Int+import Data.List+import Data.Monoid+import Database.PostgreSQL.Simple+import Database.PostgreSQL.Simple.Types+import GHC.Generics++import Database.PostgreSQL.ORM.Model+import Database.PostgreSQL.ORM.Association+import Database.PostgreSQL.ORM.SqlType++-- | This is a helper class used to extract the row types. You don't+-- need to use this class. If you are creating custom types, just+-- declare an instance of 'SqlType'.+class GDefTypes f where+ gDefTypes :: f p -> [S.ByteString]+instance (SqlType c) => GDefTypes (K1 i c) where+ gDefTypes ~(K1 c) = [sqlType c]+instance (GDefTypes a, GDefTypes b) => GDefTypes (a :*: b) where+ gDefTypes ~(a :*: b) = gDefTypes a ++ gDefTypes b+instance (GDefTypes f) => GDefTypes (M1 i c f) where+ gDefTypes ~(M1 fp) = gDefTypes fp++customModelCreateStatement :: forall a.+ (Model a, Generic a, GDefTypes (Rep a)) =>+ [(S.ByteString, S.ByteString)]+ -- ^ A list of @(@/field/@,@/type/@)@ pairs to overwrite the default+ -- SQL types of fields.+ -> [S.ByteString]+ -- ^ A list of extra table constraints.+ -> a+ -- ^ A non-strict argument to specify which model's table you want+ -- to create. @(undefined :: YourModel)@ should be fine.+ -> Query+customModelCreateStatement except constraints a+ | not (null extraneous) =+ error $ "customCreateTableStatement: no such columns: " ++ show extraneous+ | otherwise = Query $ S.concat [+ "CREATE TABLE ", quoteIdent $ modelTable info, " ("+ , S.intercalate ", " (go types names)+ , S.concat $ concatMap (\c -> [", ", c]) constraints, ")"+ ]+ where extraneous = fst (unzip except) \\ names+ types = gDefTypes $ from a+ info = modelInfo :: ModelInfo a+ names = modelColumns info+ go (t:ts) (n:ns)+ | Just t' <- lookup n except = quoteIdent n <> " " <> t' : go ts ns+ | otherwise = quoteIdent n <> " " <> t : go ts ns+ go [] [] = []+ go _ _ = error $ "createTable: " ++ S8.unpack (modelTable info) +++ " has incorrect number of columns"++-- | Statement for creating the table corresponding to a model. Not+-- strict in its argument.+modelCreateStatement :: forall a. (Model a, Generic a, GDefTypes (Rep a))+ => a -> Query+modelCreateStatement a = customModelCreateStatement except constraints a+ where ModelCreateInfo except constraint = modelCreateInfo :: ModelCreateInfo a+ constraints = if S.null constraint then [] else [constraint]++-- | Create a the database table for a model.+modelCreate :: (Model a, Generic a, GDefTypes (Rep a)) =>+ Connection -> a -> IO Int64+modelCreate c a = execute_ c (modelCreateStatement a)++-- | Create the database table corresponding to a 'JoinTable'.+jtCreateStatement :: (Model a, Model b) => JoinTable a b -> Query+jtCreateStatement jt = Query $ S.concat [+ "CREATE TABLE ", quoteIdent $ jtTable jt, " ("+ , S.intercalate ", " $ sort [typa, typb]+ , ", UNIQUE (", S.intercalate ", " $ sort [ida, idb], "))"+ ]+ where ida = quoteIdent $ jtColumnA jt+ idb = quoteIdent $ jtColumnB jt+ refa = (undefined :: JoinTable a b -> DBRef a) jt+ refb = (undefined :: JoinTable a b -> DBRef b) jt+ typa = ida <> " " <> sqlBaseType refa <> " ON DELETE CASCADE NOT NULL"+ typb = idb <> " " <> sqlBaseType refb <> " ON DELETE CASCADE NOT NULL"++-- | Create a join table in the database.+jtCreate :: (Model a, Model b) => Connection -> JoinTable a b -> IO Int64+jtCreate c jt = execute_ c (jtCreateStatement jt)
+ Database/PostgreSQL/ORM/DBSelect.hs view
@@ -0,0 +1,383 @@+{-# LANGUAGE Trustworthy #-}+{-# LANGUAGE DeriveGeneric #-}+{-# LANGUAGE FlexibleInstances #-}+{-# LANGUAGE OverloadedStrings #-}+{-# LANGUAGE ScopedTypeVariables #-}+{-# LANGUAGE TypeOperators #-}++module Database.PostgreSQL.ORM.DBSelect (+ -- * The DBSelect structure+ DBSelect(..), FromClause(..)+ -- * Executing DBSelects+ , dbSelectParams, dbSelect+ , renderDBSelect, buildDBSelect+ -- * Creating DBSelects+ , emptyDBSelect, expressionDBSelect+ , modelDBSelect+ , dbJoin, dbJoinModels+ , dbProject, dbProject'+ , dbNest, dbChain+ -- * Altering DBSelects+ , addWhere_, addWhere, setOrderBy, setLimit, setOffset, addExpression+ ) where++import Blaze.ByteString.Builder+import Blaze.ByteString.Builder.Char.Utf8 (fromChar)+import qualified Data.ByteString as S+import qualified Data.ByteString.Char8 as S8+import Data.Functor+import Data.Monoid+import Data.String+import Database.PostgreSQL.Simple+import Database.PostgreSQL.Simple.Types+import GHC.Generics++import Database.PostgreSQL.Escape+import Database.PostgreSQL.ORM.Model++-- | As it's name would suggest, a @FromClause@ is the part of a query+-- between the @FROM@ keyword and the @WHERE@ keyword. It can consist+-- of simple table names, @JOIN@ operations, and parenthesized+-- subqueries.+--+-- From clauses are represented in a more structured way than the+-- other fields so as to allow the possibility of collapsing join+-- relations. For instance, given a @'DBSelect' (A :. B)@ and a+-- @'DBSelect' (B :. C)@, it is desirable to be able to generate a+-- @'DBSelect' (A :. B :. C)@ in which each pair of terms involving+-- @B@ in the three-way relation is constrained according to the+-- original two queries. This functionality is provided by 'dbNest'+-- and 'dbChain', but it requires the ability to locate and replace+-- the instance of type @B@ in one 'DBSelect' with the @FromClause@ of+-- the other 'DBSelect'.+--+-- The 'fcCanonical' field is a canonical name of each type, which by+-- convention is the quoted and fully-qualified table name. Comparing+-- 'fcCanonical' is somewhat of a hack, and happens entirely at+-- runtime. It would be nicer to do this at compile time, but doing+-- so would require language extensions such as @GADTs@ of+-- @FunctionalDependencies@.+data FromClause = FromModel {+ fcVerbatim :: !Query -- ^ Verbatim SQL for a table, table @AS@+ -- alias, or parenthesized subquery.+ , fcCanonical :: !S.ByteString+ -- ^ Canonical name of the table or join relation represented by+ -- this term. For @JOIN@ terms, this is always the @CROSS JOIN@+ -- of the canonical names of 'fcLeft' and 'fcRight'. This means+ -- one can locate a join given only it's type (e.g., the canonical+ -- name for @A :. B@ is always @\"a CROSS JOIN b\"@), but it does+ -- mean you have to be careful not accidentally to merge two+ -- different joins on the same types. For this reason it may be+ -- safest always to have type @b@ be a single table in 'dbNest'+ -- and 'dbChain'.+ }+ | FromJoin {+ fcLeft :: !FromClause+ , fcJoinOp :: !Query -- ^ Usually @\"JOIN\"@+ , fcRight :: !FromClause+ , fcOnClause :: !Query -- ^ @ON@ or @USING@ clause (or empty)+ , fcCanonical :: !S.ByteString+ }+ deriving Show++nullFrom :: FromClause -> Bool+nullFrom (FromModel q _) | qNull q = True+nullFrom _ = False++-- | A deconstructed SQL select statement that allows easier+-- manipulation of individual terms. Several functions are provided+-- to combine the 'selFields', 'selFrom', and 'selWhere' clauses of+-- muliple @DBSelect@ structures. Other clauses may be discarded when+-- combining queries with join operations. Hence it is advisable to+-- set the other clauses at the end (or, if you set these fields, to+-- collapse your 'DBSelect' structure into a subquery using+-- `dbProject'`).+data DBSelect a = DBSelect {+ selWith :: !Query+ , selSelectKeyword :: !Query+ -- ^ By default @\"SELECT\"@, but might usefully be set to+ -- something else such as @\"SELECT DISTINCT\"@ in some+ -- situations.+ , selFields :: Query+ , selFrom :: !FromClause+ , selWhereKeyword :: !Query+ -- ^ Empty by default, but set to @\"WHERE\"@ if any @WHERE@+ -- clauses are added to the 'selWhere' field.+ , selWhere :: !Query+ , selGroupBy :: !Query+ , selHaving :: !Query+ -- below here, should appear outside any union+ , selOrderBy :: !Query+ , selLimit :: !Query+ , selOffset :: !Query+ } deriving (Generic)++instance Show (DBSelect a) where+ show = S8.unpack . fromQuery . renderDBSelect++space :: Builder+space = fromChar ' '++qNull :: Query -> Bool+qNull = S.null . fromQuery++qBuilder :: Query -> Builder+qBuilder = fromByteString . fromQuery++toQuery :: Builder -> Query+toQuery = Query . toByteString++buildFromClause :: FromClause -> Builder+buildFromClause (FromModel q _) | qNull q = mempty+buildFromClause cl0 = fromByteString " FROM " <> go cl0+ where go (FromModel q _) = qBuilder q+ go (FromJoin left joinkw right onClause _) = mconcat [+ fromChar '(', go left, space, qBuilder joinkw, space, go right+ , if qNull onClause then mempty else space <> qBuilder onClause+ , fromChar ')' ]++class GDBS f where+ gdbsDefault :: f p+ gdbsQuery :: f p -> Builder+instance GDBS (K1 i Query) where+ gdbsDefault = K1 (Query S.empty)+ gdbsQuery (K1 q) | qNull q = mempty+ | otherwise = space <> qBuilder q+instance GDBS (K1 i FromClause) where+ gdbsDefault = K1 (FromModel "" "")+ gdbsQuery (K1 fc) = buildFromClause fc+instance (GDBS a, GDBS b) => GDBS (a :*: b) where+ gdbsDefault = gdbsDefault :*: gdbsDefault+ gdbsQuery (a :*: b) = gdbsQuery a <> gdbsQuery b+instance (GDBS f) => GDBS (M1 i c f) where+ gdbsDefault = M1 gdbsDefault+ gdbsQuery = gdbsQuery . unM1++-- | A 'DBSelect' structure with keyword @\"SELECT\"@ and everything+-- else empty.+emptyDBSelect :: DBSelect a+emptyDBSelect = (to gdbsDefault) { selSelectKeyword = fromString "SELECT" }++-- | A 'DBSelect' for one or more comma-separated expressions, rather+-- than for a table. For example, to issue the query @\"SELECT+-- lastval()\"@:+--+-- > lastval :: DBSelect (Only DBKeyType)+-- > lastval = expressionDBSelect "lastval ()"+-- >+-- > ...+-- > [just_inserted_id] <- dbSelect conn lastval+--+-- On the other hand, for such a simple expression, you might as well+-- call 'query_' directly.+expressionDBSelect :: (Model r) => Query -> DBSelect r+expressionDBSelect q = emptyDBSelect { selFields = q }++-- | Create a 'Builder' for a rendered version of a 'DBSelect'. This+-- can save one string copy if you want to embed one query inside+-- another as a subquery, as done by `dbProject'`, and thus need to+-- parenthesize it. However, the function is probably not a useful+-- for end users.+buildDBSelect :: DBSelect a -> Builder+buildDBSelect dbs = gdbsQuery $ from dbs++-- | Turn a 'DBSelect' into a 'Query' suitable for the 'query' or+-- 'query_' functions.+renderDBSelect :: DBSelect a -> Query+renderDBSelect = Query . S.tail . toByteString . buildDBSelect+-- S.tail is because the rendering inserts an extra space at the beginning++catQueries :: Query -> Query -> Query -> Query+catQueries left delim right+ | qNull left = right+ | qNull right = left+ | otherwise = Query $ S.concat $ map fromQuery [left, delim, right]++-- | Add a where clause verbatim to a 'DBSelect'. The clause must+-- /not/ contain the @WHERE@ keyword (which is added automatically by+-- @addWhere_@ if needed). If the @DBSelect@ has existing @WHERE@+-- clauses, the new clause is appended with @AND@. If the query+-- contains any @\'?\'@ characters, they will be rendered into the+-- query and matching parameters will later have to be filled in via a+-- call to 'dbSelectParams'.+addWhere_ :: Query -> DBSelect a -> DBSelect a+addWhere_ q dbs+ | qNull q = dbs+ | otherwise = dbs { selWhereKeyword = "WHERE"+ , selWhere = catQueries (selWhere dbs) " AND " q }++-- | Add a where clause, and pre-render parameters directly into the+-- clause. The argument @p@ must have exactly as many fields as there+-- are @\'?\'@ characters in the 'Query'. Example:+--+-- > bars <- dbSelect c $ addWhere "bar_id = ?" (Only target_id) $+-- > (modelDBSelect :: DBSelect Bar)+addWhere :: (ToRow p) => Query -> p -> DBSelect a -> DBSelect a+addWhere q p dbs+ | qNull q = dbs+ | otherwise = dbs {+ selWhereKeyword = "WHERE"+ , selWhere = if qNull $ selWhere dbs+ then toQuery clause+ else toQuery $ qBuilder (selWhere dbs) <>+ fromByteString " AND " <> clause+ }+ where clause = mconcat [fromChar '(', buildSql q p, fromChar ')']++-- | Set the @ORDER BY@ clause of a 'DBSelect'. Example:+--+-- > dbSelect c $ setOrderBy "\"employeeName\" DESC NULLS FIRST" $+-- > modelDBSelect+setOrderBy :: Query -> DBSelect a -> DBSelect a+setOrderBy (Query ob) dbs = dbs { selOrderBy = Query $ "ORDER BY " <> ob }++-- | Set the @LIMIT@ clause of a 'DBSelect'.+setLimit :: Int -> DBSelect a -> DBSelect a+setLimit i dbs = dbs { selLimit = fmtSql "LIMIT ?" (Only i) }++-- | Set the @OFFSET@ clause of a 'DBSelect'.+setOffset :: Int -> DBSelect a -> DBSelect a+setOffset i dbs = dbs { selOffset = fmtSql "OFFSET ?" (Only i) }++-- | Add one or more comma-separated expressions to 'selFields' that+-- produce column values without any corresponding relation in the+-- @FROM@ clause. Type @r@ is the type into which the expression is+-- to be parsed. Generally this will be an instance of 'FromRow' that+-- is a degenerate model (e.g., 'Only', or a tuple).+--+-- For example, to rank results by the field @value@ and compute the+-- fraction of overall value they contribute:+--+-- > r <- dbSelect c $ addExpression+-- > "rank() OVER (ORDER BY value), value::float4/SUM(value) OVER ()"+-- > modelDBSelect+-- > :: IO [Bar :. (Int, Double)]+addExpression :: (Model r) => Query -> DBSelect a -> DBSelect (a :. r)+addExpression q dbs = dbs {+ selFields = if qNull $ selFields dbs then q+ else Query $ S.concat $ map fromQuery [selFields dbs, ", ", q]+ }++-- | A 'DBSelect' that returns all rows of a model.+modelDBSelect :: forall a. (Model a) => DBSelect a+modelDBSelect = r+ where mi = modelIdentifiers :: ModelIdentifiers a+ r = emptyDBSelect {+ selFields = Query $ S.intercalate ", " $ modelQColumns mi+ , selFrom = FromModel (Query $ modelQTable mi) (modelQTable mi)+ }++-- | Run a 'DBSelect' query on parameters. The number of @\'?\'@+-- characters embedeed in various fields of the 'DBSelect' must+-- exactly match the number of fields in parameter type @p@. Note the+-- order of arguments is such that the 'DBSelect' can be pre-rendered+-- and the parameters supplied later. Hence, you should use this+-- version when the 'DBSelect' is static. For dynamically modified+-- 'DBSelect' structures, you may prefer 'dbSelect'.+dbSelectParams :: (Model a, ToRow p) => DBSelect a -> Connection -> p -> IO [a]+{-# INLINE dbSelectParams #-}+dbSelectParams dbs = \c p -> map lookupRow <$> query c q p+ where {-# NOINLINE q #-}+ q = renderDBSelect dbs++-- | Run a 'DBSelect' query and return the resulting models.+dbSelect :: (Model a) => Connection -> DBSelect a -> IO [a]+{-# INLINE dbSelect #-}+dbSelect c dbs = map lookupRow <$> query_ c q+ where {-# NOINLINE q #-}+ q = renderDBSelect dbs++-- | Create a join of the 'selFields', 'selFrom', and 'selWhere'+-- clauses of two 'DBSelect' queries. Other fields are simply taken+-- from the second 'DBSelect', meaning fields such as 'selWith',+-- 'selGroupBy', and 'selOrderBy' in the in the first 'DBSelect' are+-- entirely ignored.+dbJoin :: forall a b.+ (Model a, Model b) =>+ DBSelect a -- ^ First table+ -> Query -- ^ Join keyword (@\"JOIN\"@, @\"LEFT JOIN\"@, etc.)+ -> DBSelect b -- ^ Second table+ -> Query -- ^ Predicate (if any) including @ON@ or @USING@ keyword+ -> DBSelect (a :. b)+dbJoin left joinOp right onClause = addWhere_ (selWhere left) right {+ selFields = Query $ S.concat [fromQuery $ selFields left, ", ",+ fromQuery $ selFields right]+ , selFrom = newfrom+ }+ where idab = modelIdentifiers :: ModelIdentifiers (a :. b)+ newfrom | nullFrom $ selFrom right = selFrom left+ | nullFrom $ selFrom left = selFrom right+ | otherwise = FromJoin (selFrom left) joinOp (selFrom right)+ onClause (modelQTable idab)++-- | A version of 'dbJoin' that uses 'modelDBSelect' for the joined+-- tables.+dbJoinModels :: (Model a, Model b) =>+ Query -- ^ Join keyword+ -> Query -- ^ @ON@ or @USING@ predicate+ -> DBSelect (a :. b)+dbJoinModels kw on = dbJoin modelDBSelect kw modelDBSelect on++-- | Restrict the fields returned by a DBSelect to be those of a+-- single 'Model' @a@. It only makes sense to do this if @a@ is part+-- of @something_containing_a@, but no static check is performed that+-- this is the case. If you @dbProject@ a type that doesn't make+-- sense, you will get a runtime error from a failed database query.+dbProject :: forall a something_containing_a.+ (Model a) => DBSelect something_containing_a -> DBSelect a+{-# INLINE dbProject #-}+dbProject dbs = r+ where sela = modelDBSelect :: DBSelect a+ r = dbs { selFields = selFields sela }++-- | Like 'dbProject', but renders the entire input 'DBSelect' as a+-- subquery. Hence, you can no longer mention fields of models other+-- than @a@ that might be involved in joins. The two advantages of+-- this approach are 1) that you can once again join to tables that+-- were part of the original query without worrying about row aliases,+-- and 2) that all terms of the 'DBSelect' will be faithrully rendered+-- into the subquery (whereas otherwise they could get dropped by join+-- operations). Generally you will still want to use 'dbProject', but+-- @dbProject'@ is available when needed.+dbProject' :: forall a something_containing_a.+ (Model a) => DBSelect something_containing_a -> DBSelect a+dbProject' dbs = r+ where sela = modelDBSelect :: DBSelect a+ ida = modelIdentifiers :: ModelIdentifiers a+ Just mq = modelQualifier ida+ q = toQuery $ fromChar '(' <>+ buildDBSelect dbs { selFields = selFields sela } <>+ fromByteString ") AS " <> fromByteString mq+ r = sela { selFrom = FromModel q $ modelQTable ida }++mergeFromClauses :: S.ByteString -> FromClause -> FromClause -> FromClause+mergeFromClauses canon left right =+ case go left of+ (fc, 1) -> fc+ (_, 0) -> error $ "mergeFromClauses could not find " ++ show canon+ (_, _) -> error $ "mergeFromClauses found duplicate " ++ show canon+ where go fc | fcCanonical fc == canon = (right, 1 :: Int)+ go (FromJoin l op r on ffc) =+ case (go l, go r) of+ ((lfc, ln), (rfc, rn)) -> (FromJoin lfc op rfc on ffc, ln + rn)+ go fc = (fc, 0)++-- | Nest two type-compatible @JOIN@ queries. As with 'dbJoin',+-- fields of the first @JOIN@ (the @'DBSelect' (a :. b)@) other than+-- 'selFields', 'selFrom', and 'selWhere' are entirely ignored.+dbNest :: forall a b c. (Model a, Model b) =>+ DBSelect (a :. b) -> DBSelect (b :. c) -> DBSelect (a :. b :. c)+dbNest left right = addWhere_ (selWhere left) right {+ selFields = fields+ , selFrom = mergeFromClauses nameb (selFrom left) (selFrom right)+ }+ where nameb = modelQTable (modelIdentifiers :: ModelIdentifiers b)+ acols = modelQColumns (modelIdentifiers :: ModelIdentifiers a)+ colcomma c r = fromByteString c <> fromByteString ", " <> r+ fields = toQuery $ foldr colcomma (qBuilder $ selFields right)+ acols++-- | Like 'dbNest', but projects away the middle type @b@.+dbChain :: (Model a, Model b, Model c) =>+ DBSelect (a :. b) -> DBSelect (b :. c) -> DBSelect (a :. c)+dbChain left right = dbProject $ dbNest left right
+ Database/PostgreSQL/ORM/Model.hs view
@@ -0,0 +1,1083 @@+{-# LANGUAGE DeriveDataTypeable #-}+{-# LANGUAGE DefaultSignatures #-}+{-# LANGUAGE FlexibleContexts #-}+{-# LANGUAGE FlexibleInstances #-}+{-# LANGUAGE ScopedTypeVariables #-}+{-# LANGUAGE TypeOperators #-}+{-# LANGUAGE OverloadedStrings #-}+{-# LANGUAGE GeneralizedNewtypeDeriving #-}+{-# LANGUAGE CPP #-}++-- | The main database ORM interface. This module contains+-- functionality for moving a Haskell data structure in and out of a+-- database table.+--+-- The most important feature is the 'Model' class, which encodes a+-- typed database interface (i.e., the ORM layer). This class has a+-- default implementation for types that are members of the 'Generic'+-- class (using GHC's @DeriveGeneric@ extension), provided the+-- following conditions hold:+--+-- 1. The data type must have a single constructor that is defined+-- using record selector syntax.+--+-- 2. The very first field of the data type must be a 'DBKey' to+-- represent the primary key. Other orders will cause a+-- compilation error.+--+-- 3. Every field of the data structure must be an instance of+-- 'FromField' and 'ToField'.+--+-- If these three conditions hold and your database naming scheme+-- follows the conventions of 'defaultModelInfo'--namely that the+-- table name is the same as the type name with the first character+-- downcased, and the field names are the same as the column names--+-- then it is reasonable to have a completely empty (default) instance+-- declaration:+--+-- > data MyType = MyType { myKey :: !DBKey+-- > , myName :: !S.ByteString+-- > , myCamelCase :: !Int+-- > , ...+-- > } deriving (Show, Generic)+-- > instance Model MyType+--+-- The default 'modelInfo' method is called 'defaultModelInfo'. You+-- may wish to use almost all of the defaults, but tweak a few things.+-- This is easily accomplished by overriding a few fields of the+-- default structure. For example, suppose your database columns use+-- exactly the same name as your Haskell field names, but the name of+-- your database table is not the same as the name of the Haskell data+-- type. You can override the database table name (field 'modelTable')+-- as follows:+--+-- > instance Model MyType where+-- > modelInfo = defaultModelInfo { modelTable = "my_type" }+--+-- Finally, if you dislike the conventions followed by+-- 'defaultModelInfo', you can simply implement an alternate pattern.+-- An example of this is 'underscoreModelInfo', which strips a prefix+-- off every field name and converts everything from camel-case to+-- underscore notation:+--+-- > instance Model MyType where+-- > modelInfo = underscoreModelInfo "my"+--+-- The above code will associate @MyType@ with a database table+-- @my_type@ having column names @key@, @name@, @camel_case@, etc.+--+-- You can implement other patterns like 'underscoreModelInfo' by+-- calling 'defaultModelInfo' and modifying the results.+-- Alternatively, you can directly call the lower-level functions from+-- which 'defaultModelInfo' is built ('defaultModelTable',+-- 'defaultModelColumns', 'defaultModelGetPrimaryKey').+module Database.PostgreSQL.ORM.Model (+ -- * The Model class+ Model(..), ModelInfo(..), ModelIdentifiers(..), ModelQueries(..)+ , underscoreModelInfo+ -- * Data types for holding primary keys+ , DBKeyType, DBKey(..), isNullKey+ , DBRef, DBRefUnique, GDBRef(..), mkDBRef+ -- * Database operations on Models+ , findAll, findRow, save, trySave, destroy, destroyByRef+ -- * Functions for accessing and using Models+ , modelName, primaryKey, modelSelectFragment+ , LookupRow(..), UpdateRow(..), InsertRow(..)+ -- * Table aliases+ , As(..), fromAs, toAs, RowAlias(..)+ -- * Low-level functions providing manual access to defaults+ , defaultModelInfo+ , defaultModelTable, defaultModelColumns, defaultModelGetPrimaryKey+ , defaultModelIdentifiers+ , defaultModelWrite+ , defaultModelQueries+ , defaultModelLookupQuery, defaultModelUpdateQuery+ , defaultModelInsertQuery, defaultModelDeleteQuery+ -- * Helper functions and miscellaneous internals+ , quoteIdent, NormalRef(..), UniqueRef(..)+ , ModelCreateInfo(..), emptyModelCreateInfo+ , defaultFromRow, defaultToRow+ , printq+ -- ** Helper classes+ -- $HelperClasses+ , GPrimaryKey0, GColumns, GDatatypeName+ , GFromRow, GToRow+ ) where++import Control.Applicative+import Control.Exception+import Control.Monad+import qualified Data.ByteString as S+import qualified Data.ByteString.Char8 as S8+import Data.Char+import Data.Data+import Data.Int+import Data.Maybe+import Data.Monoid+import Data.List hiding (find)+import Data.String+import Database.PostgreSQL.Simple+import Database.PostgreSQL.Simple.FromField+import Database.PostgreSQL.Simple.FromRow+import Database.PostgreSQL.Simple.ToField+import Database.PostgreSQL.Simple.ToRow+import Database.PostgreSQL.Simple.Types+import Database.PostgreSQL.ORM.Validations+import GHC.Generics++import Data.RequireSelector+import Database.PostgreSQL.Escape (quoteIdent)++-- | A type large enough to hold database primary keys. Do not use+-- this type directly in your data structures. Use 'DBKey' to hold a+-- `Model`'s primary key and 'DBRef' to reference the primary key of+-- another model.+type DBKeyType = Int64++-- | The type of the Haskell data structure field containing a model's+-- primary key.+--+-- Every 'Model' must have exactly one @DBKey@, and the @DBKey@ must+-- be the `Model`'s very first field in the Haskel data type+-- definition. (The ordering is enforced by+-- 'defaultModelGetPrimaryKey', which, through use of the+-- @DeriveGeneric@ extension, fails to compile when the first field is+-- not a @DBKey@.)+--+-- Each 'Model' stored in the database should have a unique non-null+-- primary key. However, the key is determined at the time the+-- 'Model' is inserted into the database. While you are constructing+-- a new 'Model' to insert, you will not have its key. Hence, you+-- should use the value @NullKey@ to let the database chose the key.+--+-- If you wish to store a `Model`'s primary key as a reference in+-- another 'Model', do not copy the 'DBKey' structure. Use 'mkDBRef'+-- to convert the `Model`'s primary key to a foreign key reference.+data DBKey = DBKey !DBKeyType | NullKey deriving (Data, Typeable)++instance Eq DBKey where+ (DBKey a) == (DBKey b) = a == b+ _ == _ = error "compare NullKey"+instance Ord DBKey where+ compare (DBKey a) (DBKey b) = compare a b+ compare _ _ = error "compare NullKey"++instance Show DBKey where+ showsPrec n (DBKey k) = showsPrec n k+ showsPrec _ NullKey = ("NullKey" ++)++instance FromField DBKey where+ fromField _ Nothing = pure NullKey+ fromField f bs = DBKey <$> fromField f bs+instance ToField DBKey where+ toField (DBKey k) = toField k+ toField NullKey = toField Null++-- | Returns 'True' when a 'DBKey' is 'NullKey'.+isNullKey :: DBKey -> Bool+isNullKey NullKey = True+isNullKey _ = False+++-- | Many operations can take either a 'DBRef' or a 'DBRefUnique'+-- (both of which consist internally of a 'DBKeyType'). Hence, these+-- two types are just type aliases to a generalized reference type+-- @GDBRef@, where @GDBRef@'s first type argument, @reftype@, is a+-- phantom type denoting the flavor of reference ('NormalRef' or+-- 'UniqueRef').+newtype GDBRef reftype table = DBRef DBKeyType+ deriving (Eq, Data, Typeable, Num, Integral, Real, Ord, Enum, Bounded)++instance (Model t) => Show (GDBRef rt t) where+ showsPrec n (DBRef k) = showsPrec n k+instance (Model t) => Read (GDBRef rt t) where+ readsPrec n str = map wrap $ readsPrec n str+ where wrap (k, s) = (DBRef k, s)+instance FromField (GDBRef rt t) where+ {-# INLINE fromField #-}+ fromField f bs = DBRef <$> fromField f bs+instance ToField (GDBRef rt t) where+ {-# INLINE toField #-}+ toField (DBRef k) = toField k++-- | Phantom type for instantiating 'GDBRef' that represents a one-to-many+-- relationship between tables.+data NormalRef = NormalRef deriving (Show, Data, Typeable)++-- | A @DBRef T@ represents a many-to-one relationship between tables. For+-- example, if type @A@ contains a @DBRef B@, then each @B@ is associated+-- with many @A@'s. By contrast, a @'DBRefUnique'@ represents a one-to-one+-- relationship.+--+-- @DBRef@ is a type alias of kind @* -> *@. The type @DBRef T@+-- references an instance of type @T@ by the primary key of its+-- database row. The type argument @T@ should be an instance of+-- 'Model'.+type DBRef = GDBRef NormalRef++-- | Phantom type for instantiating 'GDBRef' that represents a one-to-one+-- relationship between tables.+data UniqueRef = UniqueRef deriving (Show, Data, Typeable)++-- | A @DBRefUnique T@ represents a one-to-one relationship between types. For+-- example, if type @A@ contains a @DBRefUnique B@, then each @A@ is associated+-- with one (or at most one) @B@, and each @B@ has one (or at most one) @A@+-- associated with it.+--+-- By contrast, a @'DBRef'@ represents a many-to-one relationship.+type DBRefUnique = GDBRef UniqueRef+-- Functionally, @DBRefUnique@ and @DBRef@ are treated the same by+-- this module. However, other modules make a distinction. In+-- particular, the 'modelCreateStatement' corresponding to a+-- 'DBRefUnique' will include a @UNIQUE@ constraint.++-- | Create a reference to the primary key of a 'Model', suitable for+-- storing in a 'DBRef' or 'DBRefUnique' field of a different 'Model'.+mkDBRef :: (Model a) => a -> GDBRef rt a+mkDBRef a+ | (DBKey k) <- primaryKey a = DBRef k+ | otherwise = error $ "mkDBRef " ++ S8.unpack (modelName a) ++ ": NullKey"+++-- | A @ModelInfo T@ contains the information necessary for mapping+-- @T@ to a database table. Each @'Model'@ type has a single+-- @ModelInfo@ associated with it, accessible through the 'modelInfo'+-- method of the 'Model' class. Note the table and column names must+-- all be unquoted in this data structure, as they will later be+-- quoted using 'quoteIdent' by the 'modelIdentifiers' method.+data ModelInfo a = ModelInfo {+ modelTable :: !S.ByteString+ -- ^ The name of the database table corresponding to this model.+ -- The default 'modelInfo' instance uses 'defaultModelTable',+ -- which is the name of your data type with the first letter+ -- downcased.+ , modelColumns :: ![S.ByteString]+ -- ^ The names of the database columns corresponding to fields of+ -- this model. The column names should appear in the order in+ -- which the fields are defined in the Haskell data type @a@+ -- (which should also be the order in which 'modelRead' parses+ -- them to an @a@ and 'modelWrite' marshalls them).+ --+ -- Note that all queries generated by the library specify explicit+ -- column names. Hence the order of columns does not need to+ -- match their order in the database table. They should instead+ -- match the order of fields in the Haskell data structure.+ --+ -- The default, given by 'defaultModelColumns', is to use the+ -- Haskell field names for @a@. This default will fail to compile+ -- if @a@ is not defined using record syntax.+ , modelPrimaryColumn :: !Int+ -- ^ The 0-based index of the primary key column in+ -- 'modelColumns'. This should be 0 when your data structure's+ -- first field is its 'DBKey' (highly recommended, and required by+ -- 'defaultModelGetPrimaryKey'). If you customize this field, you+ -- must also customize 'modelGetPrimaryKey'--no check is made that+ -- the two are consistent.+ , modelGetPrimaryKey :: !(a -> DBKey)+ -- ^ Return the primary key of a particular model instance. If+ -- you customize this field, you must also customize+ -- 'modelPrimaryColumn'--no check is made that the two are+ -- consistent.+ }++instance Show (ModelInfo a) where+ show a = intercalate " " [+ "Model", show $ modelTable a, show $ modelColumns a+ , show $ modelPrimaryColumn a , "?"]+++-- $HelperClasses+--+-- These classes are used internally to manipulate the 'Rep'+-- representations of 'Generic' data structures. You should not be+-- defining instances of or using these classes directly. The names+-- are exported so that you can include them in the context of the+-- type signatures of your functions, should you wish to make use of+-- the various @default@... funcitons in this file.++-- | This class returns the name of a datatype.+class GDatatypeName f where+ gDatatypeName :: f p -> String+instance (Datatype c) => GDatatypeName (D1 c f) where + gDatatypeName a = datatypeName a+-- | The default name of the database table corresponding to a Haskell+-- type. The default is the same as the type name with the first+-- letter converted to lower-case. (The rationale is that Haskell+-- requires types to start with a capital letter, but all-lower-case+-- table names are easier to use in queries because PostgreSQL+-- generally does not require them to be quoted.)+defaultModelTable :: (Generic a, GDatatypeName (Rep a)) => a -> S.ByteString+defaultModelTable = fromString . caseFold. gDatatypeName . from+ where caseFold (h:t) = toLower h:t+ caseFold s = s++-- | This class extracts the field names of a Haskell data structure. Only+-- defined for types with a single constructor that uses record syntax.+class GColumns f where+ gColumns :: f p -> [S.ByteString]+instance GColumns U1 where+ gColumns _ = []+instance (Selector c, RequireSelector c) => GColumns (M1 S c f) where+ gColumns s = [fromString $ selName s]+instance (GColumns a, GColumns b) => GColumns (a :*: b) where+ gColumns ~(a :*: b) = gColumns a ++ gColumns b+instance (GColumns f) => GColumns (M1 C c f) where+ gColumns ~(M1 fp) = gColumns fp+instance (GColumns f) => GColumns (M1 D c f) where+ gColumns ~(M1 fp) = gColumns fp+-- | Returns the Haskell field names in a data structure.+defaultModelColumns :: (Generic a, GColumns (Rep a)) => a -> [S.ByteString]+defaultModelColumns = gColumns . from++-- | This class extracts the first field in a data structure when the+-- field is of type 'DBKey'. If you get a compilation error because+-- of this class, then move the 'DBKey' first in your data structure.+class GPrimaryKey0 f where+ gPrimaryKey0 :: f p -> DBKey+instance (RequireSelector c) => GPrimaryKey0 (S1 c (K1 i DBKey)) where+ {-# INLINE gPrimaryKey0 #-}+ gPrimaryKey0 (M1 (K1 k)) = k+instance (GPrimaryKey0 a) => GPrimaryKey0 (a :*: b) where+ {-# INLINE gPrimaryKey0 #-}+ gPrimaryKey0 (a :*: _) = gPrimaryKey0 a+instance (GPrimaryKey0 f) => GPrimaryKey0 (C1 c f) where+ {-# INLINE gPrimaryKey0 #-}+ gPrimaryKey0 (M1 fp) = gPrimaryKey0 fp+instance (GPrimaryKey0 f) => GPrimaryKey0 (D1 c f) where+ {-# INLINE gPrimaryKey0 #-}+ gPrimaryKey0 (M1 fp) = gPrimaryKey0 fp++-- | Extract the primary key of type 'DBKey' from a model when the+-- 'DBKey' is the first element of the data structure. Fails to+-- compile if the first field is not of type 'DBKey'.+defaultModelGetPrimaryKey :: (Generic a, GPrimaryKey0 (Rep a)) => a -> DBKey+{-# INLINE defaultModelGetPrimaryKey #-}+defaultModelGetPrimaryKey = gPrimaryKey0 . from+++class GFromRow f where+ gFromRow :: RowParser (f p)+instance GFromRow U1 where+ {-# INLINE gFromRow #-}+ gFromRow = return U1+instance (FromField c) => GFromRow (K1 i c) where+ {-# INLINE gFromRow #-}+ gFromRow = K1 <$> field+instance (GFromRow a, GFromRow b) => GFromRow (a :*: b) where+ {-# INLINE gFromRow #-}+ gFromRow = (:*:) <$> gFromRow <*> gFromRow+instance (GFromRow f) => GFromRow (M1 i c f) where+ {-# INLINE gFromRow #-}+ gFromRow = M1 <$> gFromRow+-- | This function provides a 'fromRow' function for 'Generic' types,+-- suitable as a default of the 'FromRow' class. This module uses it+-- as the default implementation of 'modelRead'.+defaultFromRow :: (Generic a, GFromRow (Rep a)) => RowParser a+{-# INLINE defaultFromRow #-}+defaultFromRow = to <$> gFromRow+++class GToRow f where+ gToRow :: f p -> [Action]+instance GToRow U1 where+ gToRow _ = []+instance (ToField c) => GToRow (K1 i c) where+ gToRow (K1 c) = [toField c]+instance (GToRow a, GToRow b) => GToRow (a :*: b) where+ gToRow (a :*: b) = gToRow a ++ gToRow b+instance (GToRow f) => GToRow (M1 i c f) where+ gToRow (M1 fp) = gToRow fp+-- | This function provides a 'toRow' function for 'Generic' types+-- that marshalls each field of the data type in the order in which it+-- appears in the type definition. This function is /not/ a suitable+-- implementation of 'modelWrite' (since it marshals the primary key,+-- which is not supposed to be written). However, it is required+-- internally by 'defaultModelWrite', and exposed in the unlikely+-- event it is of use to alternate generic 'modelWrite' functions.+-- You probably don't want to call this function.+defaultToRow :: (Generic a, GToRow (Rep a)) => a -> [Action]+defaultToRow = gToRow . from++-- | Removes a single element from the list at the position specified.+-- (Internal)+deleteAt :: Int -> [a] -> [a]+deleteAt 0 (_:t) = t+deleteAt n (h:t) = h:deleteAt (n-1) t+deleteAt _ _ = []++-- | Returns a series of 'Action's serializing each field of a data+-- structure (in the order of the Haskell datatype definition),+-- /except/ the primary key, since the primary key should never be+-- written to a database. Every field must be an instance of+-- 'ToField'.+defaultModelWrite :: forall a. (Model a, Generic a, GToRow (Rep a))+ => a -> [Action]+{-# INLINE defaultModelWrite #-}+defaultModelWrite a = deleteAt pki $ defaultToRow a+ where pki = modelPrimaryColumn (modelInfo :: ModelInfo a)++-- | The default definition of 'modelInfo'. See the documentation at+-- 'Model' for more information. Sets 'modelTable' to the name of the+-- type with the first character converted to lower-case. Sets+-- 'modelColumns' to the names of the Haskell field selectors. Sets+-- 'modelPrimaryColumn' to @0@ and extracts the first field of the+-- structure for 'modelGetPrimaryKey'. Will fail to compile unless+-- the data structure is defined with record syntax and that its first+-- field is of type 'DBKey'.+--+-- Note that defaults for the individual fields are available in+-- separate functions (e.g., 'defaultModelTable') with fewer class+-- requirements in the context, in case you want to make piecemeal use+-- of defaults. The default for 'modelPrimaryColumn' is 0. If you+-- overwrite that, you will need to overwrite 'modelGetPrimaryKey' as+-- well (and likely vice versa).+defaultModelInfo :: forall a.+ (Generic a, GDatatypeName (Rep a), GColumns (Rep a)+ , GPrimaryKey0 (Rep a)) => ModelInfo a+defaultModelInfo = m+ where m = ModelInfo { modelTable = defaultModelTable a+ , modelColumns = defaultModelColumns a+ , modelPrimaryColumn = 0+ , modelGetPrimaryKey = defaultModelGetPrimaryKey+ }+ a = undefined :: a++-- | An alternate 'Model' pattern in which Haskell type and field+-- names are converted from camel-case to underscore notation. The+-- first argument is a prefix to be removed from field names (since+-- Haskell requires field names to be unique across data types, while+-- SQL allows the same column names to be used in different tables).+--+-- For example:+--+-- > data Bar = Bar {+-- > barId :: !DBKey+-- > , barNameOfBar :: !String+-- > , barParent :: !(Maybe (DBRef Bar))+-- > } deriving (Show, Generic)+-- >+-- > instance Model Bar where modelInfo = underscoreModelInfo "bar"+--+-- would associate type @Bar@ with a database table called @bar@ with+-- fields @id@, @name_of_bar@, and @parent@.+underscoreModelInfo :: (Generic a, GToRow (Rep a), GFromRow (Rep a)+ , GPrimaryKey0 (Rep a), GColumns (Rep a)+ , GDatatypeName (Rep a)) =>+ S.ByteString -> ModelInfo a+underscoreModelInfo prefix = def {+ modelTable = toUnderscore True $ modelTable def+ , modelColumns = map fixCol $ modelColumns def+ }+ where def = defaultModelInfo+ plen = S.length prefix+ fixCol c = toUnderscore False $ stripped+ where stripped | prefix `S.isPrefixOf` c = S.drop plen c+ | otherwise = c++-- | Convert a name from camel-case to underscore notation.+-- I.e., names of the form "MSizeForm" are changed to "MSize_From".+-- @skipFirst@ determines if the first character should be ignored+-- in the conversion.+toUnderscore :: Bool -> S.ByteString -> S.ByteString+toUnderscore skipFirst | skipFirst = S8.pack . skip . S8.unpack+ | otherwise = S8.pack . go True . S8.unpack+ where skip "" = ""+ skip (h:t) = toLower h : go True t+ go _ "" = ""+ go _ (h:t) | not (isUpper h) = h : go False t+ go True (h:t) = toLower h : go True t+ go False (h:t) = '_' : toLower h : go True t+++-- | SQL table and column identifiers that should be copied verbatim+-- into queries. For normal models, these will simply be quoted+-- versions of the fields in the corresponding 'ModelInfo'. However,+-- for special cases, the fields of this structure can contain+-- unquoted SQL including @JOIN@ keywords. In the case of joins,+-- different elements of 'modelQColumns' may be qualified by different+-- table names.+--+-- Note that 'modelQColumns' and 'modelQPrimaryColumn' both contain+-- table-qualified names (e.g., @\"\\\"my_type\\\".\\\"key\\\"\"@),+-- while 'modelQWriteColumns' contains only the quoted column names.+data ModelIdentifiers a = ModelIdentifiers {+ modelQTable :: !S.ByteString+ -- ^ Literal SQL for the name of the table.+ , modelQColumns :: ![S.ByteString]+ -- ^ Literal SQL for each, table-qualified column.+ , modelQPrimaryColumn :: S.ByteString+ -- ^ Literal SQL for the model's table-qualified primary key+ -- column.+ , modelQWriteColumns :: [S.ByteString]+ -- ^ Literal SQL for all the columns except the primary key.+ -- These are the columns that should be included in an @INSERT@ or+ -- @UPDATE@. Note that unlike the other fields, these column+ -- names should /not/ be table-qualified.+ , modelQualifier :: !(Maybe S.ByteString)+ -- ^ When all columns in 'modelQColumns' are qualified by the same+ -- table name, this field contains 'Just' the table name.+ -- For the ':.' type (in which different columns have different+ -- table qualifications), this field is 'Nothing'.+ --+ -- For normal models, this field will be identical to+ -- 'modelQTable'. However, for 'As' models, 'modelQTable' will+ -- contain unquoted SQL such as @\"\\\"MyType\\\" AS+ -- \\\"my_alias\\\"\"@, in which case @modelQualifier@ will+ -- contain @'Just' \"\\\"my_alias\\\"\"@.+ , modelOrigTable :: !(Maybe S.ByteString)+ -- ^ The original, unquoted name of the table representing the+ -- model in the database. Ordinarily, this should be the same as+ -- 'modelTable' in 'ModelInfo', but in the case of 'As' aliases,+ -- the 'modelTable' is an alias, and 'modelOrigTable' is the+ -- original table. 'Nothing' for joins.+ } deriving (Show)++-- | The default simply quotes the 'modelInfo' and 'modelColumns'+-- fields of 'ModelInfo' using 'quoteIdent'.+defaultModelIdentifiers :: ModelInfo a -> ModelIdentifiers a+defaultModelIdentifiers mi = ModelIdentifiers {+ modelQTable = qtable+ , modelQColumns = qcols+ , modelQPrimaryColumn = qcols !! pki+ , modelQWriteColumns = deleteAt pki $ map quoteIdent $ modelColumns mi+ , modelQualifier = Just qtable+ , modelOrigTable = Just $ modelTable mi+ }+ where qtable = quoteIdent (modelTable mi)+ qcol c = S.concat [qtable, ".", quoteIdent c]+ qcols = map qcol $ modelColumns mi+ pki = modelPrimaryColumn mi++-- | Standard CRUD (create\/read\/update\/delete) queries on a model.+data ModelQueries a = ModelQueries {+ modelLookupQuery :: !Query+ -- ^ A query template for looking up a model by its primary key.+ -- Expects a single query parameter, namely the 'DBKey' or 'DBRef'+ -- being looked up.+ , modelUpdateQuery :: !Query+ -- ^ A query template for updating an existing 'Model' in the+ -- database. Expects as query parameters a value for every column+ -- of the model /except/ the primary key, followed by the primary+ -- key. (The primary key is not written to the database, just+ -- used to select the row to change.)+ , modelInsertQuery :: !Query+ -- ^ A query template for inserting a new 'Model' in the database.+ -- The query parameters are values for all columns /except/ the+ -- primary key. The query returns the full row as stored in the+ -- database (including the values of fields, such as the primary+ -- key, that have been chosen by the database server).+ , modelDeleteQuery :: !Query+ -- ^ A query template for deleting a 'Model' from the database.+ -- Should have a single query parameter, namely the 'DBKey' of the+ -- row to delete.+ } deriving (Show)++-- | Default SQL lookup query for a model.+defaultModelLookupQuery :: ModelIdentifiers a -> Query+defaultModelLookupQuery mi = Query $ S.concat [+ modelSelectFragment mi, " WHERE ", modelQPrimaryColumn mi, " = ?"+ ]++-- | Default SQL update query for a model.+defaultModelUpdateQuery :: ModelIdentifiers a -> Query+defaultModelUpdateQuery mi = Query $ S.concat [+ "UPDATE ", modelQTable mi, " SET "+ , S.intercalate ", " $ map (<> " = ?") $ modelQWriteColumns mi+ , " WHERE ", modelQPrimaryColumn mi, " = ?"+ ]++-- | Default SQL insert query for a model.+defaultModelInsertQuery :: ModelIdentifiers a -> Query+defaultModelInsertQuery mi+ | null (modelQWriteColumns mi) = Query $ S.concat [+ "INSERT INTO ", modelQTable mi, " DEFAULT VALUES RETURNING "+ , S.intercalate ", " $ modelQColumns mi ]+ | otherwise = Query $ S.concat $ [+ "INSERT INTO ", modelQTable mi+ , " (", S.intercalate ", " $ modelQWriteColumns mi+ , ") VALUES (", S.intercalate ", " $ map (const "?") $ modelQWriteColumns mi+ , ") RETURNING ", S.intercalate ", " $ modelQColumns mi+ ]++-- | Default SQL delete query for a model.+defaultModelDeleteQuery :: ModelIdentifiers a -> Query+defaultModelDeleteQuery mi = Query $ S.concat [+ "DELETE FROM ", modelQTable mi+ , " WHERE ", modelQPrimaryColumn mi, " = ?"+ ]++-- | The default value of 'modelQueries'.+defaultModelQueries :: ModelIdentifiers a -> ModelQueries a+defaultModelQueries mi = ModelQueries {+ modelLookupQuery = defaultModelLookupQuery mi+ , modelUpdateQuery = defaultModelUpdateQuery mi+ , modelInsertQuery = defaultModelInsertQuery mi+ , modelDeleteQuery = defaultModelDeleteQuery mi+ }++-- | Extra information for "Database.PostgreSQL.ORM.CreateTable". You+-- probably don't need to use this.+data ModelCreateInfo a = ModelCreateInfo {+ modelCreateColumnTypeExceptions :: ![(S.ByteString, S.ByteString)]+ -- ^ A list of (column-name, type) pairs for which you want to+ -- override the default.+ , modelCreateExtraConstraints :: !S.ByteString+ -- ^ Extra constraints to stick at the end of the @CREATE TABLE@+ -- statement.+ } deriving (Show)++-- | A 'ModelCreateInfo' that doesn't imply any extra constraints or+-- exceptions.+emptyModelCreateInfo :: ModelCreateInfo a+emptyModelCreateInfo = ModelCreateInfo {+ modelCreateColumnTypeExceptions = []+ , modelCreateExtraConstraints = S.empty+ }++-- | The class of data types that represent a database table. This+-- class conveys information necessary to move a Haskell data+-- structure in and out of a database table. The most important field+-- is 'modelInfo', which describes the database table and column+-- names. 'modelInfo' has a reasonable default implementation for+-- types that are members of the 'Generic' class (using GHC's+-- @DeriveGeneric@ extension), provided the following conditions hold:+--+-- 1. The data type must have a single constructor that is defined+-- using record selector syntax.+--+-- 2. The very first field of the data type must be a 'DBKey' to+-- represent the primary key. Other orders will cause a+-- compilation error.+--+-- 3. Every field of the data structure must be an instance of+-- 'FromField' and 'ToField'.+--+-- If these three conditions hold and your database naming scheme+-- follows the conventions of 'defaultModelInfo'--namely that the+-- table name is the same as the type name with the first character+-- downcased, and the field names are the same as the column names--+-- then it is reasonable to have a completely empty (default) instance+-- declaration:+--+-- > data MyType = MyType { myKey :: !DBKey+-- > , myName :: !S.ByteString+-- > , myCamelCase :: !Int+-- > , ...+-- > } deriving (Show, Generic)+-- > instance Model MyType+--+-- The default 'modelInfo' method is called 'defaultModelInfo'. You+-- may wish to use almost all of the defaults, but tweak a few things.+-- This is easily accomplished by overriding a few fields of the+-- default structure. For example, suppose your database columns use+-- exactly the same name as your Haskell field names, but the name of+-- your database table is not the same as the name of the Haskell data+-- type. You can override the database table name (field+-- 'modelTable') as follows:+--+-- > instance Model MyType where+-- > modelInfo = defaultModelInfo { modelTable = "my_type" }+--+-- Finally, if you dislike the conventions followed by+-- 'defaultModelInfo', you can simply implement an alternate pattern.+-- An example of this is 'underscoreModelInfo', which strips a prefix+-- off every field name and converts everything from camel-case to+-- underscore notation:+--+-- > instance Model MyType where+-- > modelInfo = underscoreModelInfo "my"+--+-- The above code will associate @MyType@ with a database table+-- @my_type@ having column names @key@, @name@, @camel_case@, etc.+--+-- You can implement other patterns like 'underscoreModelInfo' by+-- calling 'defaultModelInfo' and modifying the results.+-- Alternatively, you can directly call the lower-level functions from+-- which 'defaultModelInfo' is built ('defaultModelTable',+-- 'defaultModelColumns', 'defaultModelGetPrimaryKey').+class Model a where+ -- | @modelInfo@ provides information about how the Haskell data+ -- type is stored in the database, in the form of a 'ModelInfo' data+ -- structure. Among other things, this structure specifies the name+ -- of the database table, the names of the database columns+ -- corresponding to the Haskell data structure fields, and the+ -- position of the primary key in both the database columns and the+ -- Haskell data structure.+ modelInfo :: ModelInfo a+ default modelInfo :: (Generic a, GDatatypeName (Rep a), GColumns (Rep a)+ , GPrimaryKey0 (Rep a)) => ModelInfo a+ {-# INLINE modelInfo #-}+ modelInfo = defaultModelInfo++ -- | 'modelIdentifiers' contains the table and column names verbatim+ -- as they should be inserted into SQL queries. For normal models,+ -- these are simply double-quoted (with 'quoteIdent') versions of+ -- the names in 'modelInfo', with the column names qualified by the+ -- double-quoted table name. However, for special cases such as+ -- join relations (with ':.') or row aliases (with 'As'),+ -- 'modelIdentifiers' can modify the table name with unquoted SQL+ -- identifiers (such as @JOIN@ and @AS@) and change the qualified+ -- column names appropriately.+ modelIdentifiers :: ModelIdentifiers a+ {-# INLINE modelIdentifiers #-}+ modelIdentifiers = defaultModelIdentifiers modelInfo++ -- | @modelRead@ converts from a database 'query' result to the+ -- Haskell data type of the @Model@, namely @a@. Note that if type+ -- @a@ is an instance of 'FromRow', a fine definition of @modelRead@+ -- is @modelRead = fromRow@. The default is to construct a row+ -- parser using the 'Generic' class. However, it is crucial that+ -- the columns be parsed in the same order they are listed in the+ -- 'modelColumns' field of @a@'s 'ModelInfo' structure, and this+ -- should generally be the same order they are defined in the+ -- Haskell data structure. Hence @modelRead@ should generally look+ -- like:+ --+ -- @+ -- -- Call 'field' as many times as there are fields in your type+ -- modelRead = Constructor \<$> 'field' \<*> 'field' \<*> 'field'+ -- @+ modelRead :: RowParser a+ default modelRead :: (Generic a, GFromRow (Rep a)) => RowParser a+ {-# INLINE modelRead #-}+ modelRead = defaultFromRow++ -- | Marshal all fields of @a@ /except/ the primary key. As with+ -- 'modelRead', the fields must be marshalled in the same order the+ -- corresponding columns are listed in 'modelColumns', only with the+ -- primary key (generally column 0) deleted.+ --+ -- Do /not/ define this as 'toRow', even if @a@ is an instance of+ -- 'ToRow', because 'toRow' would include the primary key.+ -- Similarly, do /not/ define this as 'defaultToRow'. On the other+ -- hand, it is reasonable for @modelWrite@ to return an error for+ -- degenerate models (such as joins) that should never be 'save'd.+ modelWrite :: a -> [Action]+ default modelWrite :: (Generic a, GToRow (Rep a)) => a -> [Action]+ {-# INLINE modelWrite #-}+ modelWrite = defaultModelWrite++ -- | @modelQueries@ provides pre-formatted 'Query' templates for+ -- 'findRow', 'save', and 'destroy'. The default 'modelQueries'+ -- value is generated from 'modelIdentifiers' and should not be+ -- modified. However, for degenerate tables (such as joins created+ -- with ':.'), it is reasonable to make 'modelQueries' always throw+ -- an exception, thereby disallowing ordinary queries and requiring+ -- use of more general query functions.+ --+ -- This method should either throw an exception or use the default+ -- implementation.+ modelQueries :: ModelQueries a+ {-# INLINE modelQueries #-}+ modelQueries = defaultModelQueries modelIdentifiers++ -- | Extra constraints, if any, to place in a @CREATE TABLE@+ -- statement. Only used by "Database.PostgreSQL.ORM.CreateTable".+ modelCreateInfo :: ModelCreateInfo a+ modelCreateInfo = emptyModelCreateInfo++ -- | Perform a validation of the model, returning any errors if+ -- it is invalid.+ modelValid :: a -> [InvalidError]+ modelValid = const []++-- | Degenerate instances of 'Model' for types in the 'ToRow' class+-- are to enable extra 'ToRow' types to be included with ':.' in the+-- result of 'dbSelect' queries.+degen_err :: a+degen_err = error "Attempt to use degenerate ToRow instance as Model"+#define DEGENERATE(ctx,t) \+instance ctx => Model t where \+ modelInfo = degen_err; \+ modelIdentifiers = degen_err; \+ modelRead = fromRow; \+ modelWrite _ = degen_err; \+ modelCreateInfo = degen_err;++DEGENERATE(FromField t, (Only t))+DEGENERATE(FromField t, [t])+DEGENERATE((FromField a, FromField b), (a, b))+DEGENERATE((FromField a, FromField b, FromField c), (a, b, c))+DEGENERATE((FromField a, FromField b, FromField c, FromField d), (a, b, c, d))+DEGENERATE((FromField a, FromField b, FromField c, FromField d, FromField e), + (a, b, c, d, e))++#undef DEGEN_ERR+#undef DEGENERATE++joinModelIdentifiers :: forall a b. (Model a, Model b)+ => ModelIdentifiers (a :. b)+joinModelIdentifiers = r+ where r = ModelIdentifiers {+ modelQTable = qtable+ , modelQColumns = modelQColumns mia ++ modelQColumns mib+ , modelQWriteColumns = error "attempt to write join relation"+ , modelQPrimaryColumn =+ error "attempt to use primary key of join relation"+ , modelQualifier = Nothing+ , modelOrigTable = Nothing+ }+ qtable | S.null $ modelQTable mib = modelQTable mia+ | S.null $ modelQTable mia = modelQTable mib+ | otherwise = S.concat [modelQTable mia, " CROSS JOIN "+ , modelQTable mib]+ mia = modelIdentifiers :: ModelIdentifiers a+ mib = modelIdentifiers :: ModelIdentifiers b++-- | A degenerate instance of model representing a database join. The+-- ':.' instance does not allow normal model operations such as+-- 'findRow', 'save', and 'destroy'. Attempts to use such functions+-- will result in an exception.+instance (Model a, Model b) => Model (a :. b) where+ modelInfo = error "attempt to access ModelInfo of join type :."+ modelIdentifiers = joinModelIdentifiers+ modelRead = (:.) <$> modelRead <*> modelRead+ modelWrite _ = error "attempt to write join type :. as a normal Model"+ modelQueries = error "attempt to perform standard query on join type :."+++class GUnitType f where+ gUnitTypeName :: f p -> String+instance GUnitType (C1 c U1) where+ gUnitTypeName _ = error "gUnitTypeName"+instance GUnitType V1 where+ gUnitTypeName _ = error "gUnitTypeName"+instance (Datatype c, GUnitType f) => GUnitType (D1 c f) where+ gUnitTypeName = datatypeName++-- | The class of types that can be used as tags in as 'As' alias.+-- Such types should be unit types--in other words, have exactly one+-- constructor where the constructor is nullary (take no arguments).+-- The reason for this class is that the 'Model' instance for 'As'+-- requires a way to extract the name of the row alias without having+-- a concrete instance of the type. This is provided by the+-- 'rowAliasName' method (which must be non-strict).+class RowAlias a where+ rowAliasName :: g a row -> S.ByteString+ -- ^ Return the SQL identifier for the row alias. This method must+ -- be non-strict in its argument. Hence, it should discard the+ -- argument and return the name of the alias. For example:+ --+ -- > {-# LANGUAGE OverloadedStrings #-}+ -- >+ -- > data My_alias = My_alias+ -- > instance RowAlias My_alias where rowAliasName _ = "my_alias"+ --+ -- Keep in mind that PostgreSQL folds unquoted identifiers to+ -- lower-case. However, this library quotes row aliases in @SELECT@+ -- statements, thereby preserving case. Hence, if you want to call+ -- construct a @WHERE@ clause without double-quoting row aliases in+ -- your 'Query', you should avoid capital letters in alias names.+ --+ -- A default implementation of @rowAliasName@ exists for unit types+ -- (as well as empty data declarations) in the 'Generic' class. The+ -- default converts the first character of the type name to+ -- lower-case, following the logic of 'defaultModelTable'.+ default rowAliasName :: (Generic a, GUnitType (Rep a)) =>+ g a row -> S.ByteString+ rowAliasName _ = fromString $ caseFold $ gUnitTypeName . from $ a+ where caseFold (h:t) = toLower h:t -- fold first character only+ caseFold [] = []+ a = undefined :: a++-- | The newtype @As@ can be wrapped around an existing type to give+-- it a table name alias in a query. This is necessary when a model+-- is being joined with itself, to distinguish the two joined+-- instances of the same table.+--+-- For example:+--+-- @{-\# LANGUAGE OverloadedStrings #-}+--+--data X = X+--instance 'RowAlias' X where rowAliasName = const \"x\"+--+-- \ ...+-- r <- 'dbSelect' c $ addWhere_ \"bar.bar_key = x.bar_parent\" modelDBSelect+-- :: IO [Bar :. As X Bar]+-- @+newtype As alias row = As { unAs :: row }+instance (RowAlias alias, Show row) => Show (As alias row) where+ showsPrec d as@(As row) = showParen (d > 10) $ \rest ->+ "As " ++ S8.unpack (rowAliasName as) +++ " (" ++ showsPrec 11 row (")" ++ rest)+++-- | @fromAs@ extracts the @row@ from an @'As' alias row@, but+-- constrains the type of @alias@ to be the same as its first argument+-- (which is non-strict). This can save you from explicitly+-- specifying types. For example:+--+-- > data X = X deriving (Generic)+-- > instance RowAlias X where rowAliasName = const "x"+-- >+-- > ...+-- > r <- map (\(b1 :. b2) -> (b1, fromAs X b2)) <$>+-- > dbSelect c $ addWhere \"bar.bar_key = x.bar_parent\" modelDBSelect+fromAs :: alias -> As alias row -> row+{-# INLINE fromAs #-}+fromAs _ (As row) = row++-- | A type-restricted wrapper around the 'As' constructor, under the+-- same rationale as 'fromAs'. Not strict in its first argument.+toAs :: alias -> row -> As alias row+{-# INLINE toAs #-}+toAs _ = As++aliasModelInfo :: forall a alias.+ (Model a, RowAlias alias) =>+ ModelInfo a -> ModelInfo (As alias a)+aliasModelInfo mi = r+ where alias = rowAliasName (undefined :: As alias a)+ r = mi { modelTable = alias+ , modelGetPrimaryKey = modelGetPrimaryKey mi . unAs+ }++aliasModelIdentifiers :: forall a alias. (Model a, RowAlias alias)+ => ModelInfo a -> ModelIdentifiers (As alias a)+aliasModelIdentifiers mi+ | not ok = error $ "aliasModelIdentifiers: degenerate model " +++ show (modelQTable ida )+ | otherwise = r+ where r = ModelIdentifiers {+ modelQTable = S.concat [quoteIdent orig, " AS ", alias]+ , modelQColumns = qcols+ , modelQPrimaryColumn = qcols !! pki+ , modelQWriteColumns = deleteAt pki qcols+ , modelQualifier = Just alias+ , modelOrigTable = Just orig+ }+ ida = modelIdentifiers :: ModelIdentifiers a+ ok = Just (modelQTable ida) == modelQualifier ida+ && isJust (modelOrigTable ida)+ Just orig = modelOrigTable ida+ alias = quoteIdent $ rowAliasName (undefined :: As alias a)+ qcol c = S.concat [alias, ".", quoteIdent c]+ qcols = map qcol $ modelColumns mi+ pki = modelPrimaryColumn mi++-- | A degenerate instance of 'Model' that re-names the row with a SQL+-- @AS@ keyword. This is primarily useful when joining a model with+-- itself. Hence, standard operations ('findRow', 'save', 'destroy')+-- are not allowed on 'As' models.+instance (Model a, RowAlias as) => Model (As as a) where+ {-# INLINE modelInfo #-}+ modelInfo = aliasModelInfo modelInfo+ {-# INLINE modelRead #-}+ modelRead = As <$> modelRead+ modelWrite = error "attempt to write \"As\" alias as normal Model"+ {-# INLINE modelIdentifiers #-}+ modelIdentifiers = aliasModelIdentifiers modelInfo+ modelQueries = error "attempt to perform standard query on AS table alias"+++-- | Lookup the 'modelTable' of a 'Model' (@modelName _ = 'modelTable'+-- ('modelInfo' :: 'ModelInfo' a)@).+modelName :: forall a. (Model a) => a -> S.ByteString+{-# INLINE modelName #-}+modelName _ = modelTable (modelInfo :: ModelInfo a)++-- | Lookup the primary key of a 'Model'.+primaryKey :: (Model a) => a -> DBKey+{-# INLINE primaryKey #-}+primaryKey a = modelGetPrimaryKey modelInfo a++-- | Generate a SQL @SELECT@ statement with no @WHERE@ predicate. For+-- example, 'defaultModelLookupQuery' consists of+-- @modelSelectFragment@ followed by \"@WHERE@ /primary-key/ = ?\".+modelSelectFragment :: ModelIdentifiers a -> S.ByteString+modelSelectFragment mi = S.concat [+ "SELECT ", S.intercalate ", " $ modelQColumns mi, " FROM ", modelQTable mi ]++-- | A newtype wrapper in the 'FromRow' class, permitting every model+-- to be used as the result of a database query.+newtype LookupRow a = LookupRow { lookupRow :: a } deriving (Show)+instance (Model a) => FromRow (LookupRow a) where+ fromRow = LookupRow <$> modelRead++-- | A newtype wrapper in the 'ToRow' class, which marshalls every+-- field except the primary key. For use with 'modelInsertQuery'.+newtype InsertRow a = InsertRow a deriving (Show)+instance (Model a) => ToRow (InsertRow a) where+ toRow (InsertRow a) = modelWrite a++-- | A newtype wrapper in the 'ToRow' class, which marshalls every+-- field except the primary key, followed by the primary key. For use+-- with 'modelUpdateQuery'.+newtype UpdateRow a = UpdateRow a deriving (Show)+instance (Model a) => ToRow (UpdateRow a) where+ toRow (UpdateRow a) = toRow $ InsertRow a :. Only (primaryKey a)++-- | Dump an entire model. Useful for development and debugging only,+-- as every row will be read into memory before the function returns.+--+-- Note that unlike the other primary model operations, it is OK to+-- call 'findAll' even on degenerate models such as 'As' and ':.'.+findAll :: forall r. (Model r) => Connection -> IO [r]+findAll c = action+ where mi = modelIdentifiers :: ModelIdentifiers r+ q = Query $ modelSelectFragment mi+ action = map lookupRow <$> query_ c q++-- | Follow a 'DBRef' or 'DBRefUnique' and fetch the target row from+-- the database into a 'Model' type @r@.+findRow :: forall r rt. (Model r) => Connection -> GDBRef rt r -> IO (Maybe r)+findRow c k = action+ where qs = modelQueries :: ModelQueries r+ action = do rs <- query c (modelLookupQuery qs) (Only k)+ case rs of [r] -> return $ Just $ lookupRow $ r+ _ -> return Nothing++-- | Like 'trySave' but instead of returning an 'Either', throws a+-- 'ValidationError' if the 'Model' is invalid.+save :: (Model r)+ => Connection -> r -> IO r+save c r = do+ eResp <- trySave c r+ case eResp of+ Right resp -> return resp+ Left errs -> throwIO $ ValidationError errs++-- | Write a 'Model' to the database. If the primary key is+-- 'NullKey', the item is written with an @INSERT@ query, read back+-- from the database, and returned with its primary key filled in. If+-- the primary key is not 'NullKey', then the 'Model' is written with+-- an @UPDATE@ query and returned as-is.+--+-- If the 'Model' is invalid (i.e. the return value of 'modelValid' is+-- non-empty), a list of 'InvalidError' is returned instead.+trySave :: forall r. Model r+ => Connection -> r -> IO (Either [InvalidError] r)+trySave c r | not . null $ errors = return $ Left errors+ | NullKey <- primaryKey r = do+ rs <- query c (modelInsertQuery qs) (InsertRow r)+ case rs of [r'] -> return $ Right $ lookupRow r'+ _ -> fail "save: database did not return row"+ | otherwise = do+ n <- execute c (modelUpdateQuery qs) (UpdateRow r)+ case n of 1 -> return $ Right r+ _ -> fail $ "save: database updated " ++ show n+ ++ " records"+ where qs = modelQueries :: ModelQueries r+ errors = modelValid r++-- | Remove the row corresponding to a particular data structure from+-- the database. This function only looks at the primary key in the+-- data structure. It is an error to call this function if the+-- primary key is not set.+destroy :: forall a. (Model a) => Connection -> a -> IO ()+destroy c a =+ case primaryKey a of+ NullKey -> fail "destroy: NullKey"+ DBKey k -> void $ execute c+ (modelDeleteQuery (modelQueries :: ModelQueries a)) (Only k)++-- | Remove a row from the database without fetching it first.+destroyByRef :: forall a rt. (Model a) => Connection -> GDBRef rt a -> IO ()+destroyByRef c a =+ void $ execute c (modelDeleteQuery (modelQueries :: ModelQueries a)) (Only a)++-- | Print to stdout the query statement.+printq :: Query -> IO ()+printq (Query bs) = S8.putStrLn bs+
+ Database/PostgreSQL/ORM/SqlType.hs view
@@ -0,0 +1,108 @@+{-# LANGUAGE CPP #-}+{-# LANGUAGE FlexibleInstances #-}+{-# LANGUAGE OverloadedStrings #-}+{-# LANGUAGE ScopedTypeVariables #-}++module Database.PostgreSQL.ORM.SqlType (SqlType(..), getTypeOid) where++import qualified Data.ByteString as S+import qualified Data.ByteString.Lazy as L+import Data.Int+import Data.Monoid+import qualified Data.Text as ST+import qualified Data.Text.Lazy as LT+import Data.Time+import Data.Typeable+import qualified Data.Vector as V+import Database.PostgreSQL.Simple+import Database.PostgreSQL.Simple.FromField+import Database.PostgreSQL.Simple.Time+import Database.PostgreSQL.Simple.ToField+import Database.PostgreSQL.Simple.TypeInfo.Static+import Database.PostgreSQL.Simple.Types++import Database.PostgreSQL.ORM.Model++newtype ExtractTypeOid = ExtractTypeOid Oid+instance FromField ExtractTypeOid where+ fromField f _ = return $ ExtractTypeOid $ typeOid f++-- | Retreive the 'Oid' corresponding to a type. You can subsequently+-- use the 'Oid' to call 'getTypeInfo' for more information on the+-- type.+getTypeOid :: Connection -> S.ByteString -> IO Oid+getTypeOid c tname = do+ [Only (ExtractTypeOid ti)] <- query_ c $ Query $ "SELECT NULL :: " <> tname+ return ti++-- | The class of Haskell types that can be converted to and from a+-- particular SQL type. For most instances, you only need to define+-- 'sqlBaseType'.+class (ToField a, FromField a) => SqlType a where+ sqlBaseType :: a -> S.ByteString+ -- ^ The name of the SQL type corresponding to Haskell type @a@,+ -- when a value of @a@ can be null. This is the SQL type to and+ -- from which a @'Maybe' a@ will be converted (where 'Nothing'+ -- corresponds to the SQL value null).+ sqlType :: a -> S.ByteString+ -- ^ The name of the SQL type corresponding to Haskell type @a@,+ -- when @a@ is not wrapped in 'Maybe' and hence cannot be null. If+ -- @sqlType@ is unspecified, the default is to append \"@NOT NULL@\"+ -- to 'sqlBaseType'.+ {-# INLINE sqlType #-}+ sqlType _ = (sqlBaseType (undefined :: a)) <> " NOT NULL"++#define TYPE(hs, sql) \+ instance SqlType (hs) where sqlBaseType _ = typname (sql)+TYPE(Bool, bool)+TYPE(Double, float8)+TYPE(Float, float4)+TYPE(Int16, int2)+TYPE(Int32, int4)+TYPE(Int64, int8)+TYPE(S.ByteString, text)+TYPE(L.ByteString, text)+TYPE(ST.Text, text)+TYPE(LT.Text, text)+TYPE(Oid,oid)+TYPE(LocalTime, timestamp)+TYPE(ZonedTime, timestamptz)+TYPE(TimeOfDay, time)+TYPE(UTCTime, timestamptz)+TYPE(Day, date)+TYPE(Date, date)+TYPE(ZonedTimestamp, timestamptz)+TYPE(UTCTimestamp, timestamptz)+TYPE(LocalTimestamp, timestamp)+TYPE(String, text)+TYPE(Binary S.ByteString, bytea)+TYPE(Binary L.ByteString, bytea)++#undef TYPE++instance SqlType DBKey where+ sqlType _ = "bigserial UNIQUE NOT NULL PRIMARY KEY"+ sqlBaseType _ = error "DBKey should not be wrapped in type"++instance (SqlType a) => SqlType (Maybe a) where+ sqlType _ = sqlBaseType (undefined :: a)+ sqlBaseType _ = error "Table field Maybe should not be wrapped in other type"++instance (Typeable a, SqlType a) => SqlType (V.Vector a) where+ sqlBaseType _ = sqlBaseType (undefined :: a) <> "[]"++instance (Model a) => SqlType (DBRef a) where+ sqlBaseType (DBRef k) = sqlBaseType k <> ref+ where t = modelInfo :: ModelInfo a+ Just orig = modelOrigTable (modelIdentifiers :: ModelIdentifiers a)+ ref = S.concat [+ " REFERENCES ", quoteIdent orig, "("+ , quoteIdent (modelColumns t !! modelPrimaryColumn t), ")" ]++instance (Model a) => SqlType (DBRefUnique a) where+ sqlBaseType (DBRef k) = sqlBaseType k <> ref+ where t = modelInfo :: ModelInfo a+ Just orig = modelOrigTable (modelIdentifiers :: ModelIdentifiers a)+ ref = S.concat [+ " UNIQUE REFERENCES ", quoteIdent orig , "("+ , quoteIdent (modelColumns t !! modelPrimaryColumn t), ")" ]
+ Database/PostgreSQL/ORM/Validations.hs view
@@ -0,0 +1,34 @@+{-# LANGUAGE FlexibleContexts, DeriveDataTypeable #-}+module Database.PostgreSQL.ORM.Validations where++import Control.Exception+import qualified Data.Text as T+import Data.Typeable+import qualified Data.ByteString.Char8 as S8++data InvalidError = InvalidError+ { invalidColumn :: !S8.ByteString+ , invalidError :: !S8.ByteString } deriving (Show)++newtype ValidationError = ValidationError [InvalidError]+ deriving (Show, Typeable)++instance Exception ValidationError++type ValidationFunc a = a -> [InvalidError]++validate :: (a -> Bool)+ -> S8.ByteString -- ^ Column name+ -> S8.ByteString -- ^ Error description+ -> ValidationFunc a+validate validator columnName desc = \a ->+ if validator a then+ []+ else [InvalidError columnName desc]++validateNotEmpty :: (a -> T.Text)+ -> S8.ByteString+ -> S8.ByteString+ -> ValidationFunc a+validateNotEmpty accessor = validate (not . T.null . accessor)+
+ LICENSE view
@@ -0,0 +1,675 @@+ GNU GENERAL PUBLIC LICENSE+ Version 3, 29 June 2007++ Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>+ Everyone is permitted to copy and distribute verbatim copies+ of this license document, but changing it is not allowed.++ Preamble++ The GNU General Public License is a free, copyleft license for+software and other kinds of works.++ The licenses for most software and other practical works are designed+to take away your freedom to share and change the works. By contrast,+the GNU General Public License is intended to guarantee your freedom to+share and change all versions of a program--to make sure it remains free+software for all its users. We, the Free Software Foundation, use the+GNU General Public License for most of our software; it applies also to+any other work released this way by its authors. You can apply it to+your programs, too.++ When we speak of free software, we are referring to freedom, not+price. Our General Public Licenses are designed to make sure that you+have the freedom to distribute copies of free software (and charge for+them if you wish), that you receive source code or can get it if you+want it, that you can change the software or use pieces of it in new+free programs, and that you know you can do these things.++ To protect your rights, we need to prevent others from denying you+these rights or asking you to surrender the rights. Therefore, you have+certain responsibilities if you distribute copies of the software, or if+you modify it: responsibilities to respect the freedom of others.++ For example, if you distribute copies of such a program, whether+gratis or for a fee, you must pass on to the recipients the same+freedoms that you received. You must make sure that they, too, receive+or can get the source code. And you must show them these terms so they+know their rights.++ Developers that use the GNU GPL protect your rights with two steps:+(1) assert copyright on the software, and (2) offer you this License+giving you legal permission to copy, distribute and/or modify it.++ For the developers' and authors' protection, the GPL clearly explains+that there is no warranty for this free software. For both users' and+authors' sake, the GPL requires that modified versions be marked as+changed, so that their problems will not be attributed erroneously to+authors of previous versions.++ Some devices are designed to deny users access to install or run+modified versions of the software inside them, although the manufacturer+can do so. This is fundamentally incompatible with the aim of+protecting users' freedom to change the software. The systematic+pattern of such abuse occurs in the area of products for individuals to+use, which is precisely where it is most unacceptable. Therefore, we+have designed this version of the GPL to prohibit the practice for those+products. If such problems arise substantially in other domains, we+stand ready to extend this provision to those domains in future versions+of the GPL, as needed to protect the freedom of users.++ Finally, every program is threatened constantly by software patents.+States should not allow patents to restrict development and use of+software on general-purpose computers, but in those that do, we wish to+avoid the special danger that patents applied to a free program could+make it effectively proprietary. To prevent this, the GPL assures that+patents cannot be used to render the program non-free.++ The precise terms and conditions for copying, distribution and+modification follow.++ TERMS AND CONDITIONS++ 0. Definitions.++ "This License" refers to version 3 of the GNU General Public License.++ "Copyright" also means copyright-like laws that apply to other kinds of+works, such as semiconductor masks.+ + "The Program" refers to any copyrightable work licensed under this+License. Each licensee is addressed as "you". "Licensees" and+"recipients" may be individuals or organizations.++ To "modify" a work means to copy from or adapt all or part of the work+in a fashion requiring copyright permission, other than the making of an+exact copy. The resulting work is called a "modified version" of the+earlier work or a work "based on" the earlier work.++ A "covered work" means either the unmodified Program or a work based+on the Program.++ To "propagate" a work means to do anything with it that, without+permission, would make you directly or secondarily liable for+infringement under applicable copyright law, except executing it on a+computer or modifying a private copy. Propagation includes copying,+distribution (with or without modification), making available to the+public, and in some countries other activities as well.++ To "convey" a work means any kind of propagation that enables other+parties to make or receive copies. Mere interaction with a user through+a computer network, with no transfer of a copy, is not conveying.++ An interactive user interface displays "Appropriate Legal Notices"+to the extent that it includes a convenient and prominently visible+feature that (1) displays an appropriate copyright notice, and (2)+tells the user that there is no warranty for the work (except to the+extent that warranties are provided), that licensees may convey the+work under this License, and how to view a copy of this License. If+the interface presents a list of user commands or options, such as a+menu, a prominent item in the list meets this criterion.++ 1. Source Code.++ The "source code" for a work means the preferred form of the work+for making modifications to it. "Object code" means any non-source+form of a work.++ A "Standard Interface" means an interface that either is an official+standard defined by a recognized standards body, or, in the case of+interfaces specified for a particular programming language, one that+is widely used among developers working in that language.++ The "System Libraries" of an executable work include anything, other+than the work as a whole, that (a) is included in the normal form of+packaging a Major Component, but which is not part of that Major+Component, and (b) serves only to enable use of the work with that+Major Component, or to implement a Standard Interface for which an+implementation is available to the public in source code form. A+"Major Component", in this context, means a major essential component+(kernel, window system, and so on) of the specific operating system+(if any) on which the executable work runs, or a compiler used to+produce the work, or an object code interpreter used to run it.++ The "Corresponding Source" for a work in object code form means all+the source code needed to generate, install, and (for an executable+work) run the object code and to modify the work, including scripts to+control those activities. However, it does not include the work's+System Libraries, or general-purpose tools or generally available free+programs which are used unmodified in performing those activities but+which are not part of the work. For example, Corresponding Source+includes interface definition files associated with source files for+the work, and the source code for shared libraries and dynamically+linked subprograms that the work is specifically designed to require,+such as by intimate data communication or control flow between those+subprograms and other parts of the work.++ The Corresponding Source need not include anything that users+can regenerate automatically from other parts of the Corresponding+Source.++ The Corresponding Source for a work in source code form is that+same work.++ 2. Basic Permissions.++ All rights granted under this License are granted for the term of+copyright on the Program, and are irrevocable provided the stated+conditions are met. This License explicitly affirms your unlimited+permission to run the unmodified Program. The output from running a+covered work is covered by this License only if the output, given its+content, constitutes a covered work. This License acknowledges your+rights of fair use or other equivalent, as provided by copyright law.++ You may make, run and propagate covered works that you do not+convey, without conditions so long as your license otherwise remains+in force. You may convey covered works to others for the sole purpose+of having them make modifications exclusively for you, or provide you+with facilities for running those works, provided that you comply with+the terms of this License in conveying all material for which you do+not control copyright. Those thus making or running the covered works+for you must do so exclusively on your behalf, under your direction+and control, on terms that prohibit them from making any copies of+your copyrighted material outside their relationship with you.++ Conveying under any other circumstances is permitted solely under+the conditions stated below. Sublicensing is not allowed; section 10+makes it unnecessary.++ 3. Protecting Users' Legal Rights From Anti-Circumvention Law.++ No covered work shall be deemed part of an effective technological+measure under any applicable law fulfilling obligations under article+11 of the WIPO copyright treaty adopted on 20 December 1996, or+similar laws prohibiting or restricting circumvention of such+measures.++ When you convey a covered work, you waive any legal power to forbid+circumvention of technological measures to the extent such circumvention+is effected by exercising rights under this License with respect to+the covered work, and you disclaim any intention to limit operation or+modification of the work as a means of enforcing, against the work's+users, your or third parties' legal rights to forbid circumvention of+technological measures.++ 4. Conveying Verbatim Copies.++ You may convey verbatim copies of the Program's source code as you+receive it, in any medium, provided that you conspicuously and+appropriately publish on each copy an appropriate copyright notice;+keep intact all notices stating that this License and any+non-permissive terms added in accord with section 7 apply to the code;+keep intact all notices of the absence of any warranty; and give all+recipients a copy of this License along with the Program.++ You may charge any price or no price for each copy that you convey,+and you may offer support or warranty protection for a fee.++ 5. Conveying Modified Source Versions.++ You may convey a work based on the Program, or the modifications to+produce it from the Program, in the form of source code under the+terms of section 4, provided that you also meet all of these conditions:++ a) The work must carry prominent notices stating that you modified+ it, and giving a relevant date.++ b) The work must carry prominent notices stating that it is+ released under this License and any conditions added under section+ 7. This requirement modifies the requirement in section 4 to+ "keep intact all notices".++ c) You must license the entire work, as a whole, under this+ License to anyone who comes into possession of a copy. This+ License will therefore apply, along with any applicable section 7+ additional terms, to the whole of the work, and all its parts,+ regardless of how they are packaged. This License gives no+ permission to license the work in any other way, but it does not+ invalidate such permission if you have separately received it.++ d) If the work has interactive user interfaces, each must display+ Appropriate Legal Notices; however, if the Program has interactive+ interfaces that do not display Appropriate Legal Notices, your+ work need not make them do so.++ A compilation of a covered work with other separate and independent+works, which are not by their nature extensions of the covered work,+and which are not combined with it such as to form a larger program,+in or on a volume of a storage or distribution medium, is called an+"aggregate" if the compilation and its resulting copyright are not+used to limit the access or legal rights of the compilation's users+beyond what the individual works permit. Inclusion of a covered work+in an aggregate does not cause this License to apply to the other+parts of the aggregate.++ 6. Conveying Non-Source Forms.++ You may convey a covered work in object code form under the terms+of sections 4 and 5, provided that you also convey the+machine-readable Corresponding Source under the terms of this License,+in one of these ways:++ a) Convey the object code in, or embodied in, a physical product+ (including a physical distribution medium), accompanied by the+ Corresponding Source fixed on a durable physical medium+ customarily used for software interchange.++ b) Convey the object code in, or embodied in, a physical product+ (including a physical distribution medium), accompanied by a+ written offer, valid for at least three years and valid for as+ long as you offer spare parts or customer support for that product+ model, to give anyone who possesses the object code either (1) a+ copy of the Corresponding Source for all the software in the+ product that is covered by this License, on a durable physical+ medium customarily used for software interchange, for a price no+ more than your reasonable cost of physically performing this+ conveying of source, or (2) access to copy the+ Corresponding Source from a network server at no charge.++ c) Convey individual copies of the object code with a copy of the+ written offer to provide the Corresponding Source. This+ alternative is allowed only occasionally and noncommercially, and+ only if you received the object code with such an offer, in accord+ with subsection 6b.++ d) Convey the object code by offering access from a designated+ place (gratis or for a charge), and offer equivalent access to the+ Corresponding Source in the same way through the same place at no+ further charge. You need not require recipients to copy the+ Corresponding Source along with the object code. If the place to+ copy the object code is a network server, the Corresponding Source+ may be on a different server (operated by you or a third party)+ that supports equivalent copying facilities, provided you maintain+ clear directions next to the object code saying where to find the+ Corresponding Source. Regardless of what server hosts the+ Corresponding Source, you remain obligated to ensure that it is+ available for as long as needed to satisfy these requirements.++ e) Convey the object code using peer-to-peer transmission, provided+ you inform other peers where the object code and Corresponding+ Source of the work are being offered to the general public at no+ charge under subsection 6d.++ A separable portion of the object code, whose source code is excluded+from the Corresponding Source as a System Library, need not be+included in conveying the object code work.++ A "User Product" is either (1) a "consumer product", which means any+tangible personal property which is normally used for personal, family,+or household purposes, or (2) anything designed or sold for incorporation+into a dwelling. In determining whether a product is a consumer product,+doubtful cases shall be resolved in favor of coverage. For a particular+product received by a particular user, "normally used" refers to a+typical or common use of that class of product, regardless of the status+of the particular user or of the way in which the particular user+actually uses, or expects or is expected to use, the product. A product+is a consumer product regardless of whether the product has substantial+commercial, industrial or non-consumer uses, unless such uses represent+the only significant mode of use of the product.++ "Installation Information" for a User Product means any methods,+procedures, authorization keys, or other information required to install+and execute modified versions of a covered work in that User Product from+a modified version of its Corresponding Source. The information must+suffice to ensure that the continued functioning of the modified object+code is in no case prevented or interfered with solely because+modification has been made.++ If you convey an object code work under this section in, or with, or+specifically for use in, a User Product, and the conveying occurs as+part of a transaction in which the right of possession and use of the+User Product is transferred to the recipient in perpetuity or for a+fixed term (regardless of how the transaction is characterized), the+Corresponding Source conveyed under this section must be accompanied+by the Installation Information. But this requirement does not apply+if neither you nor any third party retains the ability to install+modified object code on the User Product (for example, the work has+been installed in ROM).++ The requirement to provide Installation Information does not include a+requirement to continue to provide support service, warranty, or updates+for a work that has been modified or installed by the recipient, or for+the User Product in which it has been modified or installed. Access to a+network may be denied when the modification itself materially and+adversely affects the operation of the network or violates the rules and+protocols for communication across the network.++ Corresponding Source conveyed, and Installation Information provided,+in accord with this section must be in a format that is publicly+documented (and with an implementation available to the public in+source code form), and must require no special password or key for+unpacking, reading or copying.++ 7. Additional Terms.++ "Additional permissions" are terms that supplement the terms of this+License by making exceptions from one or more of its conditions.+Additional permissions that are applicable to the entire Program shall+be treated as though they were included in this License, to the extent+that they are valid under applicable law. If additional permissions+apply only to part of the Program, that part may be used separately+under those permissions, but the entire Program remains governed by+this License without regard to the additional permissions.++ When you convey a copy of a covered work, you may at your option+remove any additional permissions from that copy, or from any part of+it. (Additional permissions may be written to require their own+removal in certain cases when you modify the work.) You may place+additional permissions on material, added by you to a covered work,+for which you have or can give appropriate copyright permission.++ Notwithstanding any other provision of this License, for material you+add to a covered work, you may (if authorized by the copyright holders of+that material) supplement the terms of this License with terms:++ a) Disclaiming warranty or limiting liability differently from the+ terms of sections 15 and 16 of this License; or++ b) Requiring preservation of specified reasonable legal notices or+ author attributions in that material or in the Appropriate Legal+ Notices displayed by works containing it; or++ c) Prohibiting misrepresentation of the origin of that material, or+ requiring that modified versions of such material be marked in+ reasonable ways as different from the original version; or++ d) Limiting the use for publicity purposes of names of licensors or+ authors of the material; or++ e) Declining to grant rights under trademark law for use of some+ trade names, trademarks, or service marks; or++ f) Requiring indemnification of licensors and authors of that+ material by anyone who conveys the material (or modified versions of+ it) with contractual assumptions of liability to the recipient, for+ any liability that these contractual assumptions directly impose on+ those licensors and authors.++ All other non-permissive additional terms are considered "further+restrictions" within the meaning of section 10. If the Program as you+received it, or any part of it, contains a notice stating that it is+governed by this License along with a term that is a further+restriction, you may remove that term. If a license document contains+a further restriction but permits relicensing or conveying under this+License, you may add to a covered work material governed by the terms+of that license document, provided that the further restriction does+not survive such relicensing or conveying.++ If you add terms to a covered work in accord with this section, you+must place, in the relevant source files, a statement of the+additional terms that apply to those files, or a notice indicating+where to find the applicable terms.++ Additional terms, permissive or non-permissive, may be stated in the+form of a separately written license, or stated as exceptions;+the above requirements apply either way.++ 8. Termination.++ You may not propagate or modify a covered work except as expressly+provided under this License. Any attempt otherwise to propagate or+modify it is void, and will automatically terminate your rights under+this License (including any patent licenses granted under the third+paragraph of section 11).++ However, if you cease all violation of this License, then your+license from a particular copyright holder is reinstated (a)+provisionally, unless and until the copyright holder explicitly and+finally terminates your license, and (b) permanently, if the copyright+holder fails to notify you of the violation by some reasonable means+prior to 60 days after the cessation.++ Moreover, your license from a particular copyright holder is+reinstated permanently if the copyright holder notifies you of the+violation by some reasonable means, this is the first time you have+received notice of violation of this License (for any work) from that+copyright holder, and you cure the violation prior to 30 days after+your receipt of the notice.++ Termination of your rights under this section does not terminate the+licenses of parties who have received copies or rights from you under+this License. If your rights have been terminated and not permanently+reinstated, you do not qualify to receive new licenses for the same+material under section 10.++ 9. Acceptance Not Required for Having Copies.++ You are not required to accept this License in order to receive or+run a copy of the Program. Ancillary propagation of a covered work+occurring solely as a consequence of using peer-to-peer transmission+to receive a copy likewise does not require acceptance. However,+nothing other than this License grants you permission to propagate or+modify any covered work. These actions infringe copyright if you do+not accept this License. Therefore, by modifying or propagating a+covered work, you indicate your acceptance of this License to do so.++ 10. Automatic Licensing of Downstream Recipients.++ Each time you convey a covered work, the recipient automatically+receives a license from the original licensors, to run, modify and+propagate that work, subject to this License. You are not responsible+for enforcing compliance by third parties with this License.++ An "entity transaction" is a transaction transferring control of an+organization, or substantially all assets of one, or subdividing an+organization, or merging organizations. If propagation of a covered+work results from an entity transaction, each party to that+transaction who receives a copy of the work also receives whatever+licenses to the work the party's predecessor in interest had or could+give under the previous paragraph, plus a right to possession of the+Corresponding Source of the work from the predecessor in interest, if+the predecessor has it or can get it with reasonable efforts.++ You may not impose any further restrictions on the exercise of the+rights granted or affirmed under this License. For example, you may+not impose a license fee, royalty, or other charge for exercise of+rights granted under this License, and you may not initiate litigation+(including a cross-claim or counterclaim in a lawsuit) alleging that+any patent claim is infringed by making, using, selling, offering for+sale, or importing the Program or any portion of it.++ 11. Patents.++ A "contributor" is a copyright holder who authorizes use under this+License of the Program or a work on which the Program is based. The+work thus licensed is called the contributor's "contributor version".++ A contributor's "essential patent claims" are all patent claims+owned or controlled by the contributor, whether already acquired or+hereafter acquired, that would be infringed by some manner, permitted+by this License, of making, using, or selling its contributor version,+but do not include claims that would be infringed only as a+consequence of further modification of the contributor version. For+purposes of this definition, "control" includes the right to grant+patent sublicenses in a manner consistent with the requirements of+this License.++ Each contributor grants you a non-exclusive, worldwide, royalty-free+patent license under the contributor's essential patent claims, to+make, use, sell, offer for sale, import and otherwise run, modify and+propagate the contents of its contributor version.++ In the following three paragraphs, a "patent license" is any express+agreement or commitment, however denominated, not to enforce a patent+(such as an express permission to practice a patent or covenant not to+sue for patent infringement). To "grant" such a patent license to a+party means to make such an agreement or commitment not to enforce a+patent against the party.++ If you convey a covered work, knowingly relying on a patent license,+and the Corresponding Source of the work is not available for anyone+to copy, free of charge and under the terms of this License, through a+publicly available network server or other readily accessible means,+then you must either (1) cause the Corresponding Source to be so+available, or (2) arrange to deprive yourself of the benefit of the+patent license for this particular work, or (3) arrange, in a manner+consistent with the requirements of this License, to extend the patent+license to downstream recipients. "Knowingly relying" means you have+actual knowledge that, but for the patent license, your conveying the+covered work in a country, or your recipient's use of the covered work+in a country, would infringe one or more identifiable patents in that+country that you have reason to believe are valid.+ + If, pursuant to or in connection with a single transaction or+arrangement, you convey, or propagate by procuring conveyance of, a+covered work, and grant a patent license to some of the parties+receiving the covered work authorizing them to use, propagate, modify+or convey a specific copy of the covered work, then the patent license+you grant is automatically extended to all recipients of the covered+work and works based on it.++ A patent license is "discriminatory" if it does not include within+the scope of its coverage, prohibits the exercise of, or is+conditioned on the non-exercise of one or more of the rights that are+specifically granted under this License. You may not convey a covered+work if you are a party to an arrangement with a third party that is+in the business of distributing software, under which you make payment+to the third party based on the extent of your activity of conveying+the work, and under which the third party grants, to any of the+parties who would receive the covered work from you, a discriminatory+patent license (a) in connection with copies of the covered work+conveyed by you (or copies made from those copies), or (b) primarily+for and in connection with specific products or compilations that+contain the covered work, unless you entered into that arrangement,+or that patent license was granted, prior to 28 March 2007.++ Nothing in this License shall be construed as excluding or limiting+any implied license or other defenses to infringement that may+otherwise be available to you under applicable patent law.++ 12. No Surrender of Others' Freedom.++ If conditions are imposed on you (whether by court order, agreement or+otherwise) that contradict the conditions of this License, they do not+excuse you from the conditions of this License. If you cannot convey a+covered work so as to satisfy simultaneously your obligations under this+License and any other pertinent obligations, then as a consequence you may+not convey it at all. For example, if you agree to terms that obligate you+to collect a royalty for further conveying from those to whom you convey+the Program, the only way you could satisfy both those terms and this+License would be to refrain entirely from conveying the Program.++ 13. Use with the GNU Affero General Public License.++ Notwithstanding any other provision of this License, you have+permission to link or combine any covered work with a work licensed+under version 3 of the GNU Affero General Public License into a single+combined work, and to convey the resulting work. The terms of this+License will continue to apply to the part which is the covered work,+but the special requirements of the GNU Affero General Public License,+section 13, concerning interaction through a network will apply to the+combination as such.++ 14. Revised Versions of this License.++ The Free Software Foundation may publish revised and/or new versions of+the GNU General Public License from time to time. Such new versions will+be similar in spirit to the present version, but may differ in detail to+address new problems or concerns.++ Each version is given a distinguishing version number. If the+Program specifies that a certain numbered version of the GNU General+Public License "or any later version" applies to it, you have the+option of following the terms and conditions either of that numbered+version or of any later version published by the Free Software+Foundation. If the Program does not specify a version number of the+GNU General Public License, you may choose any version ever published+by the Free Software Foundation.++ If the Program specifies that a proxy can decide which future+versions of the GNU General Public License can be used, that proxy's+public statement of acceptance of a version permanently authorizes you+to choose that version for the Program.++ Later license versions may give you additional or different+permissions. However, no additional obligations are imposed on any+author or copyright holder as a result of your choosing to follow a+later version.++ 15. Disclaimer of Warranty.++ THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY+APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT+HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY+OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,+THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR+PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM+IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF+ALL NECESSARY SERVICING, REPAIR OR CORRECTION.++ 16. Limitation of Liability.++ IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF+SUCH DAMAGES.++ 17. Interpretation of Sections 15 and 16.++ If the disclaimer of warranty and limitation of liability provided+above cannot be given local legal effect according to their terms,+reviewing courts shall apply local law that most closely approximates+an absolute waiver of all civil liability in connection with the+Program, unless a warranty or assumption of liability accompanies a+copy of the Program in return for a fee.++ END OF TERMS AND CONDITIONS++ How to Apply These Terms to Your New Programs++ If you develop a new program, and you want it to be of the greatest+possible use to the public, the best way to achieve this is to make it+free software which everyone can redistribute and change under these terms.++ To do so, attach the following notices to the program. It is safest+to attach them to the start of each source file to most effectively+state the exclusion of warranty; and each file should have at least+the "copyright" line and a pointer to where the full notice is found.++ <one line to give the program's name and a brief idea of what it does.>+ Copyright (C) <year> <name of author>++ This program is free software: you can redistribute it and/or modify+ it under the terms of the GNU General Public License as published by+ the Free Software Foundation, either version 3 of the License, or+ (at your option) any later version.++ This program is distributed in the hope that it will be useful,+ but WITHOUT ANY WARRANTY; without even the implied warranty of+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the+ GNU General Public License for more details.++ You should have received a copy of the GNU General Public License+ along with this program. If not, see <http://www.gnu.org/licenses/>.++Also add information on how to contact you by electronic and paper mail.++ If the program does terminal interaction, make it output a short+notice like this when it starts in an interactive mode:++ <program> Copyright (C) <year> <name of author>+ This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.+ This is free software, and you are welcome to redistribute it+ under certain conditions; type `show c' for details.++The hypothetical commands `show w' and `show c' should show the appropriate+parts of the General Public License. Of course, your program's commands+might be different; for a GUI interface, you would use an "about box".++ You should also get your employer (if you work as a programmer) or school,+if any, to sign a "copyright disclaimer" for the program, if necessary.+For more information on this, and how to apply and follow the GNU GPL, see+<http://www.gnu.org/licenses/>.++ The GNU General Public License does not permit incorporating your program+into proprietary programs. If your program is a subroutine library, you+may consider it more useful to permit linking proprietary applications with+the library. If this is what you want to do, use the GNU Lesser General+Public License instead of this License. But first, please read+<http://www.gnu.org/philosophy/why-not-lgpl.html>.+
+ Setup.hs view
@@ -0,0 +1,2 @@+import Distribution.Simple+main = defaultMain
+ man/man1/pg_migrate.1 view
@@ -0,0 +1,90 @@+.TH pg_migrate 1 "" +.SH NAME+.PP+pg_migrate \- PostgreSQL ORM migrations runner+.SH SYNOPSIS+.IP+.nf+\f[C]+pg_migrate\ COMMAND\ [directory]+\f[]+.fi+.SH DESCRIPTION+.PP+pg_migrate is a utility for managing migrations on a PostgreSQL+database.+It allows you to run migrations from a directory, only running those not+yet applied and rollback to previous versions.+For example, in development, use pg_migrate to iterate on your database+schema, and in production, use it to retain a rollback path when pushing+code that requires a new schema.+.PP+Migrations are executable Haskell source code files that run a single+migration and corresponding rollback.+All migrations for a project should be stored in the same directory.+See pg_migrate(5) for details on how migrations are run.+.SS Migration File Names+.PP+Migrations files are underscore delimited and contain the version+followed by a descriptive name:+.IP+.nf+\f[C]+\ \ 201304021245_create_users_table.hs+\f[]+.fi+.PP+Versions are ordered lexically and can be any string not containing the+characters \[aq].\[aq] or \[aq]_\[aq].+However, a common choice is the GMT time of creation formatted in+decreasing order of significance: %Y%m%d%H%M.+.SS Database format+.PP+The only requirement on the database is that it contain a table+schema_migrations with a VARCHAR column version.+running "\f[I]pg_migrate init\f[]" will create such a table, by running+the following SQL:+.IP+.nf+\f[C]+\ \ CREATE\ TABLE\ schema_migrations\ (+\ \ \ \ version\ VARCHAR(28)+\ \ );+\f[]+.fi+.PP+When a migration is run, it\[aq]s version is inserted into this table.+When it is rolled back, the version is removed.+Maintaining all migration versions in the database allows us to easily+run only new migrations.+.SH COMMANDS+.SS migrate [directory]+.PP+Run all migrations found in \f[I]directory\f[], starting with the oldest+migrations not yet commited to the database.+If not specified, \f[I]directory\f[] is "db/migrations".+.SS rollback [directory]+.PP+Rollback the newest migration in \f[I]directory\f[] committed to the+database.+If not specified, \f[I]directory\f[] is "db/migrations".+.SS init+.PP+Prepare the database for using migrations by creating the+"schema_migrations" table.+This command will fail if such a table already exists without destroying+the existing table.+.SS dump [file]+.PP+Dump the current database schema to the \f[I]file\f[], or+"db/schema.sql" if not \f[I]file\f[] is specified.+The current implementation simply runs pg_dump(1):+.IP+.nf+\f[C]+pg_dump\ \-\-schema\-only\ \-O\ \-x+\f[]+.fi+.SH SEE ALSO+.PP+pg_migrate(5), pg_dump(1)
+ man/man5/pg_migrate.5 view
@@ -0,0 +1,44 @@+.TH pg_migrate 5 "" +.SH NAME+.PP+PostgreSQL ORM migration+.SH SYNOPSIS+.IP+.nf+\f[C]+201305041232_migration_file.hs\ COMMAND\ [\-\-with\-db\-commit]+\f[]+.fi+.SH DESCRIPTION+.PP+A Migrations is an executable Haskell source file (e.g.+a Haskell source file with a "\f[C]main\ ::\ IO\ ()\f[]" function,+runnable by \f[C]runghc\f[]).+It must respond to the commands "up" and "down" by running a migration+and rollback, respectively.+Unless the "\-\-with\-db\-commit" flag is set, the result of the+migration or rollback should not be committed to the database.+.PP+While you can implement a migration however you like, the module+\f[C]Database.PostgreSQL.Migrations\f[] in the \f[C]postgresql\-orm\f[]+package defines a function called \f[C]defaultMain\f[] that implements+most of the boiler plate functionality of a migration.+You need only implement the actual migration and rollback code.+.SH COMMANDS+.SS up+.PP+Upgrade the database by running the migration+.SS down+.PP+Downgrade the database by rolling back the migration+.SH FLAGS+.SS \-\-with\-db\-commit+.PP+MUST be included in order to actually commit the migration or rollback+to the database.+If this argument is not included, a test run is implied, and the+migration should affect the database, probably by rolling back the+transaction before exiting.+.SH SEE ALSO+.PP+pg_migrate(1), runghc(1)
+ pg_migrate.hs view
@@ -0,0 +1,28 @@+import Database.PostgreSQL.Migrate+import System.Environment+import System.Exit +import System.FilePath+import System.IO++main :: IO ()+main = do+ args <- getArgs+ ec <- case args of+ "init":[] -> initializeDb >> return ExitSuccess+ "dump":[] -> withFile (defaultMigrationsDir </> ".." </> "schema.sql")+ WriteMode $ dumpDb+ "dump":file:[] -> withFile file WriteMode $ dumpDb+ "migrate":[] -> runMigrationsForDir stdout defaultMigrationsDir+ "migrate":dir:[] -> runMigrationsForDir stdout dir+ "rollback":[] -> runRollbackForDir defaultMigrationsDir+ "rollback":dir:[] -> runRollbackForDir dir+ _ -> do+ progName <- getProgName+ putStrLn $ "Usage: " ++ progName ++ " migrate|rollback [DIRECTORY]"+ putStrLn $ " " ++ progName ++ " init"+ putStrLn $ " " ++ progName ++ " dump [FILE]"+ return $ ExitFailure 1+ if ec == ExitSuccess then+ return ()+ else exitWith ec+
+ postgresql-orm.cabal view
@@ -0,0 +1,69 @@+name: postgresql-orm+version: 0.1+cabal-version: >= 1.14+build-type: Simple+license: GPL+license-file: LICENSE+author: Amit Levy and David Mazieres+maintainer: amit@amitlevy.com+category: Databases+synopsis: An ORM (Object Relational Mapping) and migrations DSL for PostgreSQL.+data-files: man/man1/pg_migrate.1 man/man5/pg_migrate.5+description:+ An ORM (Object Relational Mapping) and migrations DSL for PostgreSQL. See+ "Database.PostgreSQL.ORM" for documentation.++executable pg_migrate+ default-language: Haskell2010+ Main-is: pg_migrate.hs+ ghc-options: -Wall+ build-depends: base < 6+ , blaze-builder+ , bytestring+ , directory+ , filepath+ , ghc-prim+ , mtl+ , postgresql-simple+ , process++library+ default-language: Haskell2010+ build-depends: base < 6+ , blaze-builder+ , bytestring+ , directory+ , filepath+ , ghc-prim+ , mtl+ , postgresql-simple+ , process+ , text+ , time+ , transformers+ , unix+ , vector+ ghc-options: -Wall -fno-warn-unused-do-bind+ exposed-modules: Data.GetField+ , Data.RequireSelector+ , Database.PostgreSQL.Devel+ , Database.PostgreSQL.Describe+ , Database.PostgreSQL.Escape+ , Database.PostgreSQL.Migrate+ , Database.PostgreSQL.Migrations+ , Database.PostgreSQL.ORM+ , Database.PostgreSQL.ORM.Association+ , Database.PostgreSQL.ORM.CreateTable+ , Database.PostgreSQL.ORM.DBSelect+ , Database.PostgreSQL.ORM.Model+ , Database.PostgreSQL.ORM.SqlType+ , Database.PostgreSQL.ORM.Validations+ other-extensions: FlexibleContexts+ , FlexibleInstances+ , FunctionalDependencies+ , MultiParamTypeClasses+ , OverlappingInstances+ , OverloadedStrings+ , ScopedTypeVariables+ , TypeOperators+ , UndecidableInstances