chapter  4
30 Pages

Datalog and bottom-up evaluation

This chapter describes a subset of Prolog which forms a natural extension to the relational algebra.

4.1.1 Motivation and definition

We have seen some of the difficulties in integrating Prolog with databases. Not only are the difficulties practical, there are also substantial theoretical issues. Hom clause logic, upon which Prolog is based, is a subset of the first-order predicate calculus, but one which preserves much of its power. Hom clause logic also inherits some of the theoretical problems of predicate calculus.