Safe Haskell	None
Language	Haskell98

Opaleye.Column

Synopsis

Documentation

null :: Column (Nullable a) Source

A NULL of any type

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

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 the maybe function.

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 the fromMaybe function

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

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.

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

Cast a column to any other type. This is safe for some conversions such as uuid to text.

data Column a Source

The Num and Fractional instances for Column a are too general. For example, they allow you to add two Column Strings. This will be fixed in a subsequent release.

Instances

Default Constant Bool (Column PGBool)
Default Constant Double (Column PGFloat8)
Default Constant Int (Column PGInt4)
Default Constant Int64 (Column PGInt8)
Default Constant String (Column PGText)
Default Constant ByteString (Column PGJsonb)
Default Constant ByteString (Column PGJson)
Default Constant ByteString (Column PGBytea)
Default Constant ByteString (Column PGJsonb)
Default Constant ByteString (Column PGJson)
Default Constant ByteString (Column PGBytea)
Default Constant Text (Column PGText)
Default Constant UTCTime (Column PGTimestamptz)
Default Constant Text (Column PGText)
Default Constant LocalTime (Column PGTimestamp)
Default Constant TimeOfDay (Column PGTime)
Default Constant Day (Column PGDate)
Default Constant UUID (Column PGUuid)
Default ViewColumnMaker String (Column a)
QueryRunnerColumnDefault a b => Default QueryRunner (Column a) b
Default Binaryspec (Column a) (Column a)
Default Constant haskell (Column sql) => Default Constant (Maybe haskell) (Column (Nullable sql))
Default Constant (CI Text) (Column PGCitext)
Default Constant (CI Text) (Column PGCitext)
Default Unpackspec (Column a) (Column a)
Default Valuesspec (Column PGInt4) (Column PGInt4)
Default NullMaker (Column a) (Column (Nullable a))
Default NullMaker (Column (Nullable a)) (Column (Nullable a))
Default ColumnMaker (Column a) (Column a)
Default Distinctspec (Column a) (Column a)
(PGNum a, PGFractional a) => Fractional (Column a)
PGNum a => Num (Column a)
Show (Column a)

data Nullable a Source

Instances

Default Constant haskell (Column sql) => Default Constant (Maybe haskell) (Column (Nullable sql))
Default NullMaker (Column a) (Column (Nullable a))
Default NullMaker (Column (Nullable a)) (Column (Nullable a))
QueryRunnerColumnDefault a b => QueryRunnerColumnDefault (Nullable a) (Maybe b)

unsafeCoerce :: Column a -> Column b Source

Deprecated: Use unsafeCoerceColumn instead

unsafeCoerceColumn :: Column a -> Column b Source

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