Containment of conjunctive queries with arithmetic expressions

We study the problem of query containment for conjunctive queries with arithmetic constraints (QWAE). Such queries arise naturally in conventional database applications, information integration, and cooperative information systems. Given two such queries Q(1) and Q(2), we propose an algorithm that decides the containment Q(2) subset of Q(1). The proposed algorithm returns a QWAE Q'(2) obtained by rewriting Q'(2) such that Q'(2) subset of Q(2). This provides partial answers to the QWAE Q(1), which would otherwise be discarded by existing standard or extended techniques for query containment.