| Copyright | 2013 Kei Hibino |
|---|---|
| License | BSD3 |
| Maintainer | ex8k.hibino@gmail.com |
| Stability | experimental |
| Portability | unknown |
| Safe Haskell | None |
| Language | Haskell2010 |
Database.Relational.Query.Projection
Description
This module defines query projection type structure and interfaces.
- data Projection c t
- width :: Projection c r -> Int
- columns :: Projection c r -> [ColumnSQL]
- untype :: Projection c r -> UntypedProjection
- unsafeFromSqlTerms :: [StringSQL] -> Projection c t
- unsafeFromQualifiedSubQuery :: Qualified SubQuery -> Projection c t
- unsafeFromScalarSubQuery :: SubQuery -> Projection c t
- unsafeFromTable :: Table r -> Projection c r
- predicateProjectionFromExpr :: Expr c (Maybe Bool) -> Projection c (Maybe Bool)
- unsafeStringSql :: Projection c r -> StringSQL
- pi :: Projection c a -> Pi a b -> Projection c b
- piMaybe :: Projection c (Maybe a) -> Pi a b -> Projection c (Maybe b)
- piMaybe' :: Projection c (Maybe a) -> Pi a (Maybe b) -> Projection c (Maybe b)
- flattenMaybe :: Projection c (Maybe (Maybe a)) -> Projection c (Maybe a)
- just :: Projection c r -> Projection c (Maybe r)
- unsafeToAggregated :: Projection Flat r -> Projection Aggregated r
- unsafeToFlat :: Projection Aggregated r -> Projection Flat r
- unsafeChangeContext :: Projection c r -> Projection c' r
- unsafeStringSqlNotNullMaybe :: HasColumnConstraint NotNull r => Projection c (Maybe r) -> StringSQL
- pfmap :: ProductConstructor (a -> b) => (a -> b) -> Projection c a -> Projection c b
- pap :: Projection c (a -> b) -> Projection c a -> Projection c b
- data ListProjection p t
- list :: [p t] -> ListProjection p t
- unsafeListFromSubQuery :: SubQuery -> ListProjection p t
- unsafeStringSqlList :: (p t -> StringSQL) -> ListProjection p t -> StringSQL
Projection data structure and interface
data Projection c t Source
Phantom typed projection. Projected into Haskell record type t.
Instances
| ProjectableApplicative (Projection c) | Compose record type |
| ProjectableFunctor (Projection c) | Compose seed of record type |
| ProjectableMaybe (Projection c) | Control phantom |
| ProjectableShowSql (Projection c) | Unsafely get SQL term from |
| SqlProjectable (Projection OverWindow) | Unsafely make |
| SqlProjectable (Projection Aggregated) | Unsafely make |
| SqlProjectable (Projection Flat) | Unsafely make |
width :: Projection c r -> Int Source
Width of Projection.
Arguments
| :: Projection c r | Source |
| -> [ColumnSQL] | Result SQL string list |
Get column SQL string list of projection.
untype :: Projection c r -> UntypedProjection Source
Unsafely get untyped projection.
unsafeFromSqlTerms :: [StringSQL] -> Projection c t Source
Unsafely generate Projection from SQL expression strings.
unsafeFromQualifiedSubQuery :: Qualified SubQuery -> Projection c t Source
Unsafely generate Projection from qualified (joined) subquery.
unsafeFromScalarSubQuery :: SubQuery -> Projection c t Source
Unsafely generate Projection from scalar subquery.
unsafeFromTable :: Table r -> Projection c r Source
Unsafely generate unqualified Projection from Table.
predicateProjectionFromExpr :: Expr c (Maybe Bool) -> Projection c (Maybe Bool) Source
Lift Expr to Projection to use as restrict predicate.
unsafeStringSql :: Projection c r -> StringSQL Source
Unsafely get SQL term from Proejction.
Projections
Arguments
| :: Projection c a | Source |
| -> Pi a b | Projection path |
| -> Projection c b | Narrower |
Trace projection path to get narrower Projection.
Arguments
| :: Projection c (Maybe a) | Source |
| -> Pi a b | Projection path |
| -> Projection c (Maybe b) | Narrower |
Trace projection path to get narrower Projection. From Maybe type to Maybe type.
Arguments
| :: Projection c (Maybe a) | Source |
| -> Pi a (Maybe b) | Projection path. |
| -> Projection c (Maybe b) | Narrower |
Trace projection path to get narrower Projection. From Maybe type to Maybe type.
Leaf type of projection path is Maybe.
flattenMaybe :: Projection c (Maybe (Maybe a)) -> Projection c (Maybe a) Source
Composite nested Maybe on projection phantom type.
just :: Projection c r -> Projection c (Maybe r) Source
Cast into Maybe on projection phantom type.
unsafeToAggregated :: Projection Flat r -> Projection Aggregated r Source
Unsafely lift to aggregated context.
unsafeToFlat :: Projection Aggregated r -> Projection Flat r Source
Unsafely down to flat context.
unsafeChangeContext :: Projection c r -> Projection c' r Source
Unsafely cast context type tag.
unsafeStringSqlNotNullMaybe :: HasColumnConstraint NotNull r => Projection c (Maybe r) -> StringSQL Source
Unsafely get SQL string expression of not null key projection.
pfmap :: ProductConstructor (a -> b) => (a -> b) -> Projection c a -> Projection c b Source
Projectable fmap of Projection type.
pap :: Projection c (a -> b) -> Projection c a -> Projection c b Source
Projectable ap of Projection type.
List Projection
data ListProjection p t Source
Projection type for row list.
list :: [p t] -> ListProjection p t Source
Make row list projection from Projection list.
unsafeListFromSubQuery :: SubQuery -> ListProjection p t Source
Make row list projection from SubQuery.
unsafeStringSqlList :: (p t -> StringSQL) -> ListProjection p t -> StringSQL Source
Map projection show operatoions and concatinate to single SQL expression.