Squeal.PostgreSQL.Expression.Composite

composite functions

Composite Functions

row

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

Arguments

:: Has tab from row

=> Alias tab

intermediate table

-> Expression grp lat with db params from (null ('PGcomposite row))

A row constructor on all columns in a table expression.

field

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"