Squeal.PostgreSQL.Session.Statement

A top-level Statement type wraps a Query or Manipulation together with an EncodeParams and a DecodeRow.

Documentation

data Statement db x y where

A Statement consists of a Manipulation or a Query that can be run in a MonadPQ.

Constructors

Manipulation

Constructor for a data manipulation language statement

Fields

• :: (All (OidOfNull db) params, SListI row)
• => EncodeParams db params x

  encoding of parameters

• -> DecodeRow row y

  decoding of returned rows

• -> Manipulation '[] db params row

  insertInto, update, or deleteFrom, ...

• -> Statement db x y

Query

Constructor for a structured query language statement

Fields

• :: (All (OidOfNull db) params, SListI row)
• => EncodeParams db params x

  encoding of parameters

• -> DecodeRow row y

  decoding of returned rows

• -> Query '[] '[] db params row

  select, values, ...

• -> Statement db x y

Instances

Profunctor (Statement db)

Defined in Squeal.PostgreSQL.Session.Statement

Methods

dimap :: (a -> b) -> (c -> d) -> Statement db b c -> Statement db a d

lmap :: (a -> b) -> Statement db b c -> Statement db a c

rmap :: (b -> c) -> Statement db a b -> Statement db a c

(#.) :: Coercible c b => q b c -> Statement db a b -> Statement db a c

(.#) :: Coercible b a => Statement db b c -> q a b -> Statement db a c

Functor (Statement db x)

Defined in Squeal.PostgreSQL.Session.Statement

Methods

fmap :: (a -> b) -> Statement db x a -> Statement db x b

(<$) :: a -> Statement db x b -> Statement db x a

RenderSQL (Statement db x y)

Defined in Squeal.PostgreSQL.Session.Statement

Methods

renderSQL :: Statement db x y -> ByteString

query

Arguments

:: (GenericParams db params x xs, GenericRow row y ys)

=> Query '[] '[] db params row

select, values, ...

-> Statement db x y

Smart constructor for a structured query language statement

manipulation

Arguments

:: (GenericParams db params x xs, GenericRow row y ys)

=> Manipulation '[] db params row

insertInto, update, or deleteFrom, ...

-> Statement db x y

Smart constructor for a data manipulation language statement

type GenericParams db params x xs = (All (OidOfNull db) params, IsProductType x xs, AllZip (ToParam db) params xs)

A GenericParams constraint to ensure that a Haskell type is a product type, all its terms have known Oids, and can be encoded to corresponding Postgres types.

type GenericRow row y ys = (IsRecord y ys, AllZip FromField row ys)

A GenericRow constraint to ensure that a Haskell type is a record type, and all its fields and can be decoded from corresponding Postgres fields.