Re: [Haskell-beginners] creating a relational tuple type

The type classes in Haskell DB are to allow manipulations on type level lists. You probably want to read the paper "Strongly typed heterogeneous collections" by Oleg Kiselyov, Ralf Lämmel, and Keean Schupke to get a sense of Haskell DB: http://homepages.cwi.nl/~ralf/HList/ To learn Haskell, writing a "less typed" relational algebra engine would be significantly easier. The early sections of the HList give simpler heterogeneous lists that don't use type level programming (but aren't as well typed).