Safe Haskell	None
Language	Haskell2010

Opaleye.Column

Description

Functions for working directly with Columns.

Please note that numeric Column types are instances of Num, so you can use *, /, +, - on them.

Synopsis

Documentation

null :: Column (Nullable a) Source #

A NULL of any type

isNull :: Column (Nullable a) -> Column PGBool Source #

TRUE if the value of the column is NULL, FALSE otherwise.

matchNullable :: Column b -> (Column a -> Column b) -> Column (Nullable a) -> Column b Source #

If the Column (Nullable a) is NULL then return the Column b otherwise map the underlying Column a using the provided function.

The Opaleye equivalent of maybe.

fromNullable :: Column a -> Column (Nullable a) -> Column a Source #

If the Column (Nullable a) is NULL then return the provided Column a otherwise return the underlying Column a.

The Opaleye equivalent of fromMaybe.

toNullable :: Column a -> Column (Nullable a) Source #

Treat a column as though it were nullable. This is always safe.

The Opaleye equivalent of Just.

maybeToNullable :: Maybe (Column a) -> Column (Nullable a) Source #

If the argument is Nothing return NULL otherwise return the provided value coerced to a nullable type.

data Column a Source #

Instances

Default Constant Bool (Column PGBool)
Methods def :: Constant Bool (Column PGBool)
Default Constant Double (Column PGFloat8)
Methods def :: Constant Double (Column PGFloat8)
Default Constant Int (Column PGInt4)
Methods def :: Constant Int (Column PGInt4)
Default Constant Int32 (Column PGInt4)
Methods def :: Constant Int32 (Column PGInt4)
Default Constant Int64 (Column PGInt8)
Methods def :: Constant Int64 (Column PGInt8)
Default Constant String (Column PGText)
Methods def :: Constant String (Column PGText)
Default Constant ByteString (Column PGJsonb)
Methods def :: Constant ByteString (Column PGJsonb)
Default Constant ByteString (Column PGJson)
Methods def :: Constant ByteString (Column PGJson)
Default Constant ByteString (Column PGBytea)
Methods def :: Constant ByteString (Column PGBytea)
Default Constant ByteString (Column PGJsonb)
Methods def :: Constant ByteString (Column PGJsonb)
Default Constant ByteString (Column PGJson)
Methods def :: Constant ByteString (Column PGJson)
Default Constant ByteString (Column PGBytea)
Methods def :: Constant ByteString (Column PGBytea)
Default Constant LocalTime (Column PGTimestamp)
Methods def :: Constant LocalTime (Column PGTimestamp)
Default Constant TimeOfDay (Column PGTime)
Methods def :: Constant TimeOfDay (Column PGTime)
Default Constant UTCTime (Column PGTimestamptz)
Methods def :: Constant UTCTime (Column PGTimestamptz)
Default Constant Day (Column PGDate)
Methods def :: Constant Day (Column PGDate)
Default Constant Text (Column PGText)
Methods def :: Constant Text (Column PGText)
Default Constant Text (Column PGText)
Methods def :: Constant Text (Column PGText)
Default Constant Value (Column PGJsonb)
Methods def :: Constant Value (Column PGJsonb)
Default Constant Value (Column PGJson)
Methods def :: Constant Value (Column PGJson)
Default Constant UUID (Column PGUuid)
Methods def :: Constant UUID (Column PGUuid)
Default ViewColumnMaker String (Column a)
Methods def :: ViewColumnMaker String (Column a)
Default RelExprMaker String (Column a)
Methods def :: RelExprMaker String (Column a)
QueryRunnerColumnDefault a b => Default QueryRunner (Column a) b
Methods def :: QueryRunner (Column a) b
(Default Constant a (Column b), IsSqlType b) => Default Constant [a] (Column (PGArray b))
Methods def :: Constant [a] (Column (PGArray b))
Default Constant haskell (Column sql) => Default Constant (Maybe haskell) (Maybe (Column sql))
Methods def :: Constant (Maybe haskell) (Maybe (Column sql))
Default Constant haskell (Column sql) => Default Constant (Maybe haskell) (Column (Nullable sql))
Methods def :: Constant (Maybe haskell) (Column (Nullable sql))
Default Constant (CI Text) (Column PGCitext)
Methods def :: Constant (CI Text) (Column PGCitext)
Default Constant (CI Text) (Column PGCitext)
Methods def :: Constant (CI Text) (Column PGCitext)
Default Unpackspec (Column a) (Column a)
Methods def :: Unpackspec (Column a) (Column a)
Default Binaryspec (Column a) (Column a)
Methods def :: Binaryspec (Column a) (Column a)
Default Valuesspec (Column a) (Column a)
Methods def :: Valuesspec (Column a) (Column a)
Default NullMaker (Column a) (Column (Nullable a))
Methods def :: NullMaker (Column a) (Column (Nullable a))
Default NullMaker (Column (Nullable a)) (Column (Nullable a))
Methods def :: NullMaker (Column (Nullable a)) (Column (Nullable a))
Default ColumnMaker (Column a) (Column a)
Methods def :: ColumnMaker (Column a) (Column a)
Default EqPP (Column a) (Column a)
Methods def :: EqPP (Column a) (Column a)
Default Distinctspec (Column a) (Column a)
Methods def :: Distinctspec (Column a) (Column a)
(PGNum a, PGFractional a) => Fractional (Column a) Source #
Methods (/) :: Column a -> Column a -> Column a # recip :: Column a -> Column a # fromRational :: Rational -> Column a #
PGNum a => Num (Column a) Source #
Methods (+) :: Column a -> Column a -> Column a # (-) :: Column a -> Column a -> Column a # (*) :: Column a -> Column a -> Column a # negate :: Column a -> Column a # abs :: Column a -> Column a # signum :: Column a -> Column a # fromInteger :: Integer -> Column a #
Show (Column a) Source #
Methods showsPrec :: Int -> Column a -> ShowS # show :: Column a -> String # showList :: [Column a] -> ShowS #
PGString a => IsString (Column a) Source #
Methods fromString :: String -> Column a #

data Nullable a Source #

Only used within a Column, to indicate that it can take null values.

Instances

Default Constant haskell (Column sql) => Default Constant (Maybe haskell) (Column (Nullable sql))
Methods def :: Constant (Maybe haskell) (Column (Nullable sql))
Default NullMaker (Column a) (Column (Nullable a))
Methods def :: NullMaker (Column a) (Column (Nullable a))
Default NullMaker (Column (Nullable a)) (Column (Nullable a))
Methods def :: NullMaker (Column (Nullable a)) (Column (Nullable a))
IsSqlType a => IsSqlType (Nullable a) Source #
Methods showPGType :: proxy (Nullable a) -> String Source #
PGOrd a => PGOrd (Nullable a) Source #

QueryRunnerColumnDefault a b => QueryRunnerColumnDefault (Nullable a) (Maybe b) Source #
Methods queryRunnerColumnDefault :: QueryRunnerColumn (Nullable a) (Maybe b) Source #

unsafeCast :: String -> Column a -> Column b Source #

Cast a column to any other type. Implements Postgres's :: or CAST( ... AS ... ) operations. This is safe for some conversions, such as uuid to text.

unsafeCoerce :: Column a -> Column b Source #

Deprecated: Use unsafeCoerceColumn instead

unsafeCoerceColumn :: Column a -> Column b Source #

Treat a Column as though it were of a different type. If such a treatment is not valid then Postgres may fail with an error at SQL run time.

unsafeCompositeField :: Column a -> String -> Column b Source #