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You can index, but iirc Prolog's indexing isn't powerful enough to efficiently handle SQL-like queries. Like, iirc `WHERE Id > 500` still requires trying all the Id values, you can't binary search on keys like that. And clause order matters a lot for perf. Doesn't Datalog use a different sort of evaluator that makes such queries more tractable?

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There's no inherent reason you couldn't do that. That's another similarity to SQL: the underlying features of the language will depend on which runtime you're using.

SQL: Postgres, SQLite, MySql, etc. all have different features. Prolog: SWI-Prolog, GNU Prolog, Scryer Prolog, etc. same thing.

It's true that Datalog is better for pure data querying. But there's no theoretical reason it couldn't be implemented in Prolog as well.

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