Logic Programming and Databases

The topic of logic programming and databases. has gained in creasing interest in recent years. Several events have marked the rapid evolution of this field: the selection, by the Japanese Fifth Generation Project, of Prolog and of the relational data model as the basis for the development of new machine archi tectures; the focusing of research in database theory on logic queries and on recursive query processing; and the pragmatic, application-oriented development of expert database systems and of knowledge-base systems. As a result, an enormous amount of work has been produced in the recent literature, coupled with the spontaneous growth of several advanced projects in this area. The goal of this book is to present a systematic overview of a rapidly evolving discipline, which is presently not described with the same approach in other books. We intend to introduce stu dents and researchers to this new discipline; thus we use a plain, tutorial style, and complement the description of algorithms with examples and exercises. We attempt to achieve a balance be tween theoretical foundations and technological issues; thus we present a careful introduction to the new language Datalog, but we also focus on the efficient interfacing of logic programming formalisms (such as Prolog and Datalog) with large databases.

1 Logic Programming and Databases: An Overview.- 1.1 Logic Programming as Query Language.- 1.2 Prolog and Datalog.- 1.3 Alternative Architectures.- 1.4 Applications.- 1.5 Bibliographic Notes.- 2 A Review of Relational Databases and Prolog.- 2.1 Overview of Relational Databases.- 2.2 Prolog: A Language for Programming in Logic.- 2.3 Bibliographic Notes.- I Coupling Prolog to Relational Databases.- 3 Prolog as a Query Language.- 4 Coupling Prolog Systems to Relational Databases.- 5 Overview of Systems for Coupling Prolog to Relational Databases.- II Foundations of Datalog.- 6 Syntax and Semantics of Datalog.- 7 Proof Theory and Evaluation Paradigms of Datalog.- III Optimization Methods for Datalog.- 8 Classification of Optimization Methods for Datalog.- 9 Evaluation Methods.- 10 Rewriting Methods.- 11 Extensions of Pure Datalog.- 12 Overview of Research Prototypes for Integrating Relational Databases and Logic Programming.