Paper #30

A. Calì, D. Lembo, R. Rosati "Intensional Query Processing in Data Integration Systems under Integrity Constraints"

Keywords: data integration, integrity constraints

In this paper we address the problem of query answering and rewriting in global-as-view data integration systems, when key and inclusion dependencies (KDs and IDs) are expressed on the global schema. In the case of sound views, we provide sound and complete rewriting techniques for a maximal class of constraints for which decidability holds. Then, we introduce a semantics which is able to cope with violations of constraints, and present a sound and complete rewriting technique for the same decidable class of constraints. Finally, we consider the decision problem of query answering and give decidability and complexity results.