Hello, I've been out of the Haskell game for a bit, but now I'm back. A couple of years ago I made a small library that implements relational algebra with types so that malformed queries and other operations are caught at compile time. It is heavily based off of the internals of HaskellDB (see http://hackage.haskell.org/packages/archive/haskelldb/2.1.1/doc/html/Databas...), but types so that it can actually be used directly instead of having to use HaskellDB's query monad. Besides the joy of using relational algebra directly in your code, this also means that you can make query-optimizing code in a type-safe way, you can subquery results returned by the database directly without accessing the database again and you have more options when converting from relation algebra to SQL or another query language. The library isn't quite ready for release, but I might want to work on it a bit and then release it. Is anyone interested in such a library? Paul Visschers