Integrity constraint checking in deductive databases using the Prolog not-predicate

Abstract

In a deductive (or relational) database, integrity constraints are data dependencies which database states are compelled to obey. Different ways of expressing integrity constraints were proposed in several papers, e.g. tuple calculus, closed first-order formula, clause, etc. In this paper, we propose a special form of closed first-order formula, called IC-formula, which uses the Prolog nested not-predicate to express integrity constraints. The IC-formulas are more expressive than other existing ways of expressing integrity constraints. The soundness and completeness of the method for verifying IC-formulas in a deductive database is proved. The full checking of the IC-formulas of a deductive database can be implemented easily by Prolog systems. Methods for doing incremental integrity constraint checking for the operations of inserting, deleting, and modifying a tuple in a relational or deductive database are presented. The concept of a key of a relation is also used to further simplify incremental integrity constraint checking. These incremental integrity constraint checking methods can be implemented easily by Prolog systems.