Database.PostgreSQL.Simple.Range

Documentation

data RangeBound a

Represents boundary of a range

Constructors

NegInfinity

Inclusive !a

Exclusive !a

PosInfinity

Instances

Functor RangeBound

Eq a => Eq (RangeBound a)

Show a => Show (RangeBound a)

data PGRange a

Generic range type

Constructors

PGRange !(RangeBound a) !(RangeBound a)

Instances

Functor PGRange

Ord a => Eq (PGRange a)

Show a => Show (PGRange a)

(FromField a, Typeable * a) => FromField (PGRange a)

ToField (PGRange Double)

ToField (PGRange Float)

ToField (PGRange Int)

ToField (PGRange Int8)

ToField (PGRange Int16)

ToField (PGRange Int32)

ToField (PGRange Int64)

ToField (PGRange Integer)

ToField (PGRange Word)

ToField (PGRange Word8)

ToField (PGRange Word16)

ToField (PGRange Word32)

ToField (PGRange Word64)

ToField (PGRange Scientific)

ToField (PGRange UTCTime)

ToField (PGRange LocalTime)

ToField (PGRange ZonedTime)

ToField (PGRange TimeOfDay)

ToField (PGRange NominalDiffTime)

ToField (PGRange Day)

ToField (PGRange Date)

ToField (PGRange ZonedTimestamp)

ToField (PGRange UTCTimestamp)

ToField (PGRange LocalTimestamp)

empty :: PGRange a

isEmpty :: Ord a => PGRange a -> Bool

Is a range empty? If this returns True, then the contains predicate will always return False. However, if this returns False, it is not necessarily true that there exists a point for which contains returns True. Consider PGRange (Excludes 2) (Excludes 3) :: PGRange Int, for example.

isEmptyBy :: (a -> a -> Ordering) -> PGRange a -> Bool

contains :: Ord a => PGRange a -> a -> Bool

Does a range contain a given point? Note that in some cases, this may not correspond exactly with a server-side computation. Consider UTCTime for example, which has a resolution of a picosecond, whereas postgresql's timestamptz types have a resolution of a microsecond. Putting such Haskell values into the database will result in them being rounded, which can change the value of the containment predicate.

containsBy :: (a -> a -> Ordering) -> PGRange a -> a -> Bool