A Fuzzy Datalog Deductive Database System

Abstract

This paper describes a proposal for a deductive database system with fuzzy Datalog as its query language. Concepts supporting the fuzzy logic programming system Bousi~Prolog are tailored to the needs of the deductive database system DES. We develop a version of fuzzy Datalog where programs and queries are compiled to the DES core Datalog language. Weak unification and weak SLD resolution are adapted for this setting, and extended to allow rules with truth degree annotations. We provide a public implementation in Prolog, which is open source, multiplatform, portable, and in-memory, featuring a graphical user interface. A distinctive feature of this system is that, unlike others, we have formally demonstrated that our implementation techniques fit the proposed operational semantics. We also study the efficiency of these implementation techniques through a series of detailed experiments. Moreover, a database example for a recommender system is used to illustrate some of the features of the system and its usefulness.