Reasoning with disjunctive constrained tuple-generating dependencies

Abstract

In extended relational databases, queries and integrity constraints often contain interpreted variables and built-in relations. We extend previous work on semantic query containment for extended relational databases to handle disjunctive constrained tuple-generating dependencies (DCTGDs) which include almost all well-known classes of integrity constraints. After defining this extended class of integrity constraints, we present a method for expanding a query Q, using DCTGDs, to a semantically equivalent set of queries. Our theorems on this method unify and generalize several previous results on semantic query containment. We apply the method to the DCTGD implication problem and prove that, when restricted to regular CTGDs, our method is strictly more powerful than previously published chase algorithms.