Overview of Research Prototypes for Integrating Relational Databases and Logic Programming

Abstract

This chapter presents an overview of some of the research prototypes which are under development for the integration of relational databases and logic programming. We present:

• a) The LDL project, under development at Microelectronics and Computer Technology Corporation (MCC) at Austin, Texas. The project’s goal is to implement an integrated system for processing queries in Logic Data Language (LDL), a language which extends Datalog.

• b) The NAIL! project·(Not Another Implementation of Logic!), under development at Stanford University with the support of NSF and IBM. NAIL! processes queries in Datalog, but interfaces a conventional SQL database system (running on IBM PC/RT).

• c) The POSTGRES system, under development at Berkeley University. POSTGRES is a large project for developing a new generation database system, extending relational technology to support complex objects, data types, and rules (called alerts or triggers); in this chapter, we focus on rule management.

• d) The FIFTH GENERATION Project, under development at the Institute for New Generation Computer Technology (ICOT) in Tokio, Japan. The guiding principle of the project is to select Prolog as unifying element for the development of computer architecture, programming style, and database approach. In this chapter, we illustrate features related to the development of knowledge bases.

• e) The Advanced Database Interface (ADE) of the KIWI Esprit project, sponsored by the EEC. KIWI is a joint effort for the development of knowledge bases, programmed through an object-oriented language (OOPS), and interfaced to an existing relational database. ADE is joint effort of the University of Calabria, of CRAI, and of ENIDATA (Italy).

• f) The ALGRES Project, under development in the frame of the METEOR Esprit project, sponsored by the EEC. The ALGRES project extends the relational model to support nonnormalized relations and a fixpoint operator, and supports Datalog as programming language. ALGRES is a joint effort of the Politecnico di Milano and of TXT-Techint (Italy).

• g) The PRISMA project, under development at the University of Twente in Enschede, the Centre for Mathematics and Computer Science in Amsterdam, and Philips Research Laboratories in Eindhoven, sponsored by the Dutch research fund SPIN. PRISMA is a large project for the development of a multiprocessor, main-memory, relational database machine that supports a logic interface, called PRISMAlog.