Datalog is specifically a non-TC subset of Prolog with a modified evaluation strategy that guarantees queries always terminate, though I was being imprecise — it’s the non-recursive subset of Datalog that’s directly equivalent to TRC (though Wikipedia shows this by mapping Datalog to relational algebra, whereas I’d argue the mapping between TRC and Datalog is even easier to demonstrate). hopefully my imprecision didn’t muddy my point — the special sauce at Prolog’s core that folks seem to fetishize is essentially ordinary database shit, and the idea of a relational database having any kind of general reasoning is plainly ridiculous.