Servant.Util.Beam.Postgres.Sorting

Converting a sorting specification to a value understandable by Beam.

Documentation

type SortingSpecApp backend (allParams :: [TyNamedParam Type]) = HList (SortingApp backend) allParams

List of SortingApp functions. Describes how to apply SortingSpec params (each of possible SortingItem) to an SQL query.

Instance of this type can be created using fieldSort function. For example:

sortingSpecApp :: SortingSpecApp ["course" ?: Course, "desc" ?: Text]
sortingSpecApp =
    fieldSort "course" courseField .*.
    fieldSort "desc" descField .*.
    HNil

Annotating fieldSort call with parameter name is not mandatory but recommended to prevent possible mistakes in fieldSorts ordering.

fieldSort :: forall (name :: Symbol) a backend. (SortingBackend backend, SortedValueConstraint backend a) => SortedValue backend a -> SortingApp backend ('TyNamedParam name a)

sortBy_ :: (backend ~ BeamSortingBackend syntax0 s0, allParams ~ AllSortingParams provided base, ApplyToSortItem backend allParams, Projectible be a, SqlOrderable be (BackendOrdering backend), ThreadRewritable (QNested s) a) => SortingSpec provided base -> (a -> SortingSpecApp backend allParams) -> Q be db (QNested s) a -> Q be db s (WithRewrittenThread (QNested s) s a)

Applies orderBy_ according to the given sorting specification.