Database.Relational.OverloadedProjection

This module provides interfaces of overloaded projections.

Documentation

class HasProjection l a b | l a -> b where

Projection interface to implement Pi with row polymorphism.

Minimal complete definition

projection

Methods

projection :: PiLabel l -> Pi a b

Orphan instances

HasProjection l a b => IsLabel l (Pi a b)

Derive IsLabel instance from HasProjection.

Methods

fromLabel :: Proxy# Symbol l -> Pi a b

(PersistableWidth a, HasProjection l a b) => IsLabel l (PI c a b)

Derive PI label.

Methods

fromLabel :: Proxy# Symbol l -> PI c a b