Differential Datalog

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…

Do note that the existing name in the CS literature for algorithms that can cheaply provide an "updated" result given a change in the input is dynamic, not differential. "Differential" actually refers to something else altogether, namely being able to automatically compute the gradient of some general calculation on continuous-valued inputs! (The intersection of differential and dynamic problems, where the point is to recompute answers quickly when some continuous-valued input changes, is called "kinetic".)…