In this case, it's even worse. Prolog is computationally complete. With everything that comes with rice's theorem. Every non-trivial property of a program being

In this case, it's even worse. Prolog is computationally complete. With everything that comes with rice's theorem. Every non-trivial property of a program being generally undecidable. Datalog, on the other hand, isn't. It's terminating, like SQL. And many program properties are indeed decidable.