deductive database system similar to Prolog
The Datalog package contains a lightweight deductive database system. Queries and database updates are expressed using Datalog -- a declarative logic language in which each formula is a function-free Horn clause, and every variable in the head of a clause must appear in the body of the clause. The use of Datalog syntax and an implementation based on tabling intermediate results, ensures that all queries terminate.
Homepage: https://datalog.sourceforge.net/