Database.PostgreSQL.PQTypes.FromSQL

Documentation

class (PQFormat t, Storable (PQBase t)) => FromSQL t where

Class which represents "from SQL (libpqtypes) type to Haskell type" transformation.

Associated Types

type PQBase t :: *

Base type (used by libpqtypes).

Methods

fromSQL

Arguments

:: Maybe (PQBase t)

base value (Nothing if NULL was delivered)

-> IO t

Convert value of base type to target one.

Instances

FromSQL Bool

FromSQL Char

FromSQL Double

FromSQL Float

FromSQL Int16

FromSQL Int32

FromSQL Int64

FromSQL Word8

FromSQL String

Assumes that source C string is UTF-8, so if you are working with a different encoding, you should not rely on this instance.

FromSQL ByteString

FromSQL Text

Assumes that source C string is UTF-8, so if you are working with a different encoding, you should not rely on this instance.

FromSQL LocalTime

FromSQL ZonedTime

FromSQL TimeOfDay

FromSQL UTCTime

FromSQL Day

FromSQL Interval

FromSQL XML

FromSQL t => FromSQL (Maybe t)

CompositeFromSQL t => FromSQL (Composite t)

FromSQL (Binary ByteString)

CompositeFromSQL t => FromSQL (CompositeArray2 t)

FromSQL t => FromSQL (Array2 t)

CompositeFromSQL t => FromSQL (CompositeArray1 t)

FromSQL t => FromSQL (Array1 t)