Datalog is more or less equivalent to SQL with recursion. I don't know of any serious, database-backed implementations but there are a lot of in-memory impleme

Datalog is more or less equivalent to SQL with recursion. I don't know of any serious, database-backed implementations but there are a lot of in-memory implementations and some interesting extensions for distributed databases. http://en.wikipedia.org/wiki/Datalog http://en.wikipedia.org/wiki/Datalog