First of all -- I want to thank you all for robust discussion on this subthread. I've learned a lot about the experience of other folks using Prolog and where t

First of all -- I want to thank you all for robust discussion on this subthread. I've learned a lot about the experience of other folks using Prolog and where they've gotten mileage out of its unique strengths. It's been eye opening to see for sure! Part of the reason I wanted to ask this question because I had a suspicion that there may not necessarily be as large of a gap between SQL and Prolog as there may initially appear. Said another way, I wondered if there was a Prolog (or Datalog) to SQL compiler used in production. I recently stumbled upon Logica [1], which appears to based on a predecessor (Yeladog) built at Google. I don't have experience using it, so I'm not sure how complete the implementation is nor how efficient it is. I'm curious if anyone has used it before and if so, what their experience was. At first blush, it appears to bring the best of both worlds: the expressive power of Prolog/Datalog, combined with the standard operational tooling of SQL which is a common core dependency in many if not most production software systems. Two questions: 1) How does Datalog compare to Prolog for common problems you might use Prolog for? Any things you can do in Prolog differentially that wouldn't be as easy in Datalog and vice versa? 2) What issues might come up in system that uses a Datalog to SQL transpiler? Given that some of the answers in this thread about the efficiency of using Prolog to do constraint solving, it seems like such an approach might lose some of the efficiency that makes it so powerful in the first place. On the other hand, if it doesn't, it seems like it'd bring a killer app to SQL, which is the ability to do constraint solving in a nearly native fashion inside SQL. [1] https://github.com/EvgSkv/logica https://github.com/EvgSkv/logica