relational-query-0.11.2.0: Typeful, Modular, Relational, algebraic query engine

Copyright2017 Kei Hibino
LicenseBSD3
Maintainerex8k.hibino@gmail.com
Stabilityexperimental
Portabilityunknown
Safe HaskellNone
LanguageHaskell2010

Database.Relational.OverloadedProjection

Contents

Description

This module provides interfaces of overloaded projections.

Synopsis

Documentation

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

Projection interface to implement Pi with row polymorphism.

Minimal complete definition

projection

Methods

projection :: PiLabel l -> Pi a b Source #

Orphan instances

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

Derive IsLabel instance from HasProjection.

Methods

fromLabel :: Pi a b #

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

Derive PI label.

Methods

fromLabel :: PI c a b #