A Multiple Answer Prolog System for Decomposing a Database into Boyce-Codd Normal Form

In this paper we present a Prolog system for decomposing a database scheme into Boye-Codd normal form, based on an algorithm called Reduction by Resolution which allows one to compare a cover for a subset of attributes without building the complete closure of the set of functional dependencies. This leads to a better time performance and also, in some cases, to polynomial complexity.