Copyright	(c) Eitan Chatav 2019
Maintainer	[email protected]
Stability	experimental
Safe Haskell	None
Language	Haskell2010

Squeal.PostgreSQL.Expression.Composite

Contents

Composite Functions

Description

composite functions

Synopsis

row :: SListI row => NP (Aliased (Expression grp lat with db params from)) row -> Expression grp lat with db params from (null (PGcomposite row))
rowStar :: Has tab from row => Alias tab -> Expression grp lat with db params from (null (PGcomposite row))
field :: (Has sch db schema, Has tydef schema (Typedef (PGcomposite row)), Has field row ty) => QualifiedAlias sch tydef -> Alias field -> Expression grp lat with db params from (NotNull (PGcomposite row)) -> Expression grp lat with db params from ty

Composite Functions

row Source #

Arguments

:: SListI row
=> NP (Aliased (Expression grp lat with db params from)) row	zero or more expressions for the row field values
-> Expression grp lat with db params from (null (PGcomposite row))

A row constructor is an expression that builds a row value (also called a composite value) using values for its member fields.

>>> :{
type Complex = 'PGcomposite
  '[ "real"      ::: 'NotNull 'PGfloat8
   , "imaginary" ::: 'NotNull 'PGfloat8 ]
:}

>>> let i = row (0 `as` #real :* 1 `as` #imaginary) :: Expression grp lat with db params from ('NotNull Complex)
>>> printSQL i
ROW((0.0 :: float8), (1.0 :: float8))

rowStar :: Has tab from row => Alias tab -> Expression grp lat with db params from (null (PGcomposite row)) Source #

A row constructor on all columns in a table expression.

field Source #

Arguments

:: (Has sch db schema, Has tydef schema (Typedef (PGcomposite row)), Has field row ty)
=> QualifiedAlias sch tydef	row type
-> Alias field	field name
-> Expression grp lat with db params from (NotNull (PGcomposite row))
-> Expression grp lat with db params from ty

>>> :{
type Complex = 'PGcomposite
  '[ "real"      ::: 'NotNull 'PGfloat8
   , "imaginary" ::: 'NotNull 'PGfloat8 ]
type Schema = '["complex" ::: 'Typedef Complex]
:}

>>> let i = row (0 `as` #real :* 1 `as` #imaginary) :: Expression lat '[] grp (Public Schema) from params ('NotNull Complex)
>>> printSQL $ i & field #complex #imaginary
(ROW((0.0 :: float8), (1.0 :: float8))::"complex")."imaginary"