I have read the "Scrap Your Boilerplate: A Practical Design Pattern for Generic Programming" and have worked out how to do it. This seems much better than using Template Haskell for this kind of problem. I used mkQ and extQ to convert from various types that are allowed in the record structure, to an algebraic enumeration type that codes the valid types. This allows using "everything (++)" to convert a record (tuple type) to a List of type-names in an enumeration. This is a very neet and compact way of doing it. This enables me to define a database table in haskell (where a record represents a table with columns of the given types), for example: data TestTable = TestTable { column1 :: ColumnType Int, column2 :: ColumnType Float, column3 :: ColumnType String } type ColumnType a = String -- use phantom types to statically type check sql... testTable :: TestTable testTable = TestTable { column1 = "id", column2 = "aFloatValue" column3 = "aString" } Using generics I can now generate a list: [("id",SqlInt),("aFloatValue",SqlFloat),("aString",SqlString)] which can be used to check the Haskell version of the table against the version in the database, or create the table if none exists... This is for a kind of port of the HaskellDB stuff to ghc, although it is more of a complete reimplementation using the same idea. My aim is to use a monad transformer, so that db operations can be interleaved with other IO. Regards, Keean Schupke.