An advanced knowledge base management system based on the integration of logic programming and relational databases

An interface implemented in the environment between PROLOG and a relational DBMS is described. In order to combine the advantages of interpreted and compiled coupling strategies, the hybrid interface uses a two-phase communication protocol. This strategy minimizes the accesses to the database and generates queries as selectively as possible to the database by maximal instantiation of the database predicates, using DBMS for relational operations whenever possible. This interface is integrated into EPSILON (a knowledge-base management system) by defining it as a new inference engine which allows the user to use logical predicates and database predicates in the same way