I always fancied a database that worked like a dynamic version of prolog, with facts that could be added over time, queries that can use inference etc. I couldn't really find anything that worked like that though, everything seemed to either have a fixed set of facts or didn't support inference. Looking for something like that is what first got me interested in differential dataflow.
The fact that this is bottom up makes me think that you probably can't go crazy with the number of rules.
The fact that this is bottom up makes me think that you probably can't go crazy with the number of rules.