LOGIC AND DATABASES

Logic and databases have gone a long way together since the advent of relational databases. Already the first basic query languages for relational databases beside relational algebra - tuple calculus and domain calculus - are actually a subset of first order predicate logic. Furthermore logic proved to be very adequate for establishing a sound theory for relational databases. When attempts were made to integrate AI and database technology in form of expert database systems or knowledge base management systems logic provided a unifying framework although several differences in the use of logic in the both fields have been discovered. The confluence of logic programming and databases triggered deductive databases as new area of research. In this overview paper we will discuss shortly the relationship between relational databases and logic and present the possibilities for coupling Prolog with databases. The main part of this paper concentrates on deductive databases, in particular on the database language Datalog. We conclude by mentioning some facets of recent research on logic and databases. The goal of this paper is to provide an overview of the most relevant developments in the field and providing pointers to the literature.