Safe Haskell	None
Language	Haskell2010

Database.Beam.Query.CTE

Synopsis

data Recursiveness be where
- Nonrecursive :: Recursiveness be
- Recursive :: IsSql99RecursiveCommonTableExpressionSelectSyntax ( BeamSqlBackendSelectSyntax be) => Recursiveness be
newtype With be (db :: ( Type -> Type ) -> Type ) a = With {
- runWith :: WriterT ( Recursiveness be, [ BeamSql99BackendCTESyntax be]) ( State Int ) a
}
data QAnyScope
data ReusableQ be db res where
- ReusableQ :: Proxy res -> ( forall s. Proxy s -> Q be db s ( WithRewrittenThread QAnyScope s res)) -> ReusableQ be db res
reusableForCTE :: forall be res db. ( ThreadRewritable QAnyScope res, Projectible be res, BeamSqlBackend be) => Text -> ReusableQ be db res
selecting :: forall res be db. ( BeamSql99CommonTableExpressionBackend be, HasQBuilder be, Projectible be res, ThreadRewritable QAnyScope res) => Q be db QAnyScope res -> With be db ( ReusableQ be db res)
reuse :: forall s be db res. ReusableQ be db res -> Q be db s ( WithRewrittenThread QAnyScope s res)

Documentation

data Recursiveness be where Source #

Constructors

Nonrecursive :: Recursiveness be
Recursive :: IsSql99RecursiveCommonTableExpressionSelectSyntax ( BeamSqlBackendSelectSyntax be) => Recursiveness be

Instances

Instances details

Semigroup ( Recursiveness be) Source #
Instance details Defined in Database.Beam.Query.CTE Methods (<>) :: Recursiveness be -> Recursiveness be -> Recursiveness be Source # sconcat :: NonEmpty ( Recursiveness be) -> Recursiveness be Source # stimes :: Integral b => b -> Recursiveness be -> Recursiveness be Source #
Monoid ( Recursiveness be) Source #
Instance details Defined in Database.Beam.Query.CTE Methods mempty :: Recursiveness be Source # mappend :: Recursiveness be -> Recursiveness be -> Recursiveness be Source # mconcat :: [ Recursiveness be] -> Recursiveness be Source #

newtype With be (db :: ( Type -> Type ) -> Type ) a Source #

Monad in which SELECT statements can be made (via selecting ) and bound to result names for re-use later. This has the advantage of only computing each result once. In SQL, this is translated to a common table expression.

Once introduced, results can be re-used in future queries with reuse .

With is also a member of MonadFix for backends that support recursive CTEs. In this case, you can use mdo or rec notation (with RecursiveDo enabled) to bind result values (again, using reuse ) even before they're introduced.

See further documentation here .

Constructors

With
Fields runWith :: WriterT ( Recursiveness be, [ BeamSql99BackendCTESyntax be]) ( State Int ) a

Instances

Instances details

Monad ( With be db) Source #
Instance details Defined in Database.Beam.Query.CTE Methods (>>=) :: With be db a -> (a -> With be db b) -> With be db b Source # (>>) :: With be db a -> With be db b -> With be db b Source # return :: a -> With be db a Source #
Functor ( With be db) Source #
Instance details Defined in Database.Beam.Query.CTE Methods fmap :: (a -> b) -> With be db a -> With be db b Source # (<$) :: a -> With be db b -> With be db a Source #
IsSql99RecursiveCommonTableExpressionSelectSyntax ( BeamSqlBackendSelectSyntax be) => MonadFix ( With be db) Source #
Instance details Defined in Database.Beam.Query.CTE Methods mfix :: (a -> With be db a) -> With be db a Source #
Applicative ( With be db) Source #
Instance details Defined in Database.Beam.Query.CTE Methods pure :: a -> With be db a Source # (<>) :: With be db (a -> b) -> With be db a -> With be db b Source # liftA2 :: (a -> b -> c) -> With be db a -> With be db b -> With be db c Source # (>) :: With be db a -> With be db b -> With be db b Source # (<*) :: With be db a -> With be db b -> With be db a Source #

data QAnyScope Source #

data ReusableQ be db res where Source #

Query results that have been introduced into a common table expression via selecting that can be used in future queries with reuse .

Constructors

ReusableQ :: Proxy res -> ( forall s. Proxy s -> Q be db s ( WithRewrittenThread QAnyScope s res)) -> ReusableQ be db res

reusableForCTE :: forall be res db. ( ThreadRewritable QAnyScope res, Projectible be res, BeamSqlBackend be) => Text -> ReusableQ be db res Source #

selecting :: forall res be db. ( BeamSql99CommonTableExpressionBackend be, HasQBuilder be, Projectible be res, ThreadRewritable QAnyScope res) => Q be db QAnyScope res -> With be db ( ReusableQ be db res) Source #

Introduce the result of a query as a result in a common table expression. The returned value can be used in future queries by applying reuse .

reuse :: forall s be db res. ReusableQ be db res -> Q be db s ( WithRewrittenThread QAnyScope s res) Source #

Introduces the result of a previous selecting (a CTE) into a new query