Extensible record
Proposals, implementations can be found on the FirstClassLabels page of Haskell' Wiki.
Papers and libraries
- HList --- a Haskell library for strongly typed heterogeneous collections includes also extensible records. Its relatedness to database programming is described in the articles, see also its possible relatedness to HaskellDB project.
- Daan Leijen: First-class labels for extensible rows. See also the description of the Haskell-like language Morrow, it is based on the concepts of the article. And Extensible records with scoped labels: "We describe a natural approach to typing polymorphic and extensible records that is simple, easy to use in practice, and straightforward to implement."
- Simon Peyton Jones and Greg Morrisett: A proposal for records in Haskell
- Mark Jones and Simon Peyton Jones: Lightweight Extensible Records for Haskell
- Mark P. Jones: A prototype implementation of extensible records for Hugs
- Didier Remy's Typing record concatenation for free on Erik Knoop's page
- Benedict R. Gaster, Mark P. Jones: A Polymorphic Type System for Extensible Records and Variants
- Chameleon, a Haskell-like language, see its records
Applications
Declarative database management
Such systems can achieve more type safety (compared to direct SQL handling).
HaskellDB
A problem where some concepts of extensible records could be useful is described in the HaskellDB project. More precisely, the problem is described in the paper downloadable from
- Chalmers version of HaskellDB (see Papers subsection on Documentation)
- which presupposes reading also paper on the Daan Leijen's original HaskellDB page (see Documentation subpage, PostScript version)
HaskellDB uses its own extensible record system, but see also HaskellDB#Future.
CoddFish
CoddFish is another declarative, type safe database system. As for extensible record system, it uses HList --- a Haskell library for strongly typed heterogeneous collections.
Related concepts
Dependent type -- as an explanation for its relatedness here, see Why Dependent Types Matter written by Thorsten Altenkirch, Conor McBride, James McKinna -- or at least its Conclusions section (section 8, pages 18--19).