---
title: "Query rewriting and answering under constraints in data integration systems"
authors:
  - "Andrea Calì"
  - "Domenico Lembo"
  - "Riccardo Rosati"
doi: ""
url: "https://ijcai.org/proceedings/2003/3"
pdf: "https://ijcai.org/proceedings/2003/0003.pdf"
venue: "Proceedings of the Eighteenth International Joint Conference on Artificial Intelligence"
year: 2003
pages: "16-20"
track: ""
keywords:
---

# Query rewriting and answering under constraints in data integration systems

Andrea Calì, Domenico Lembo, Riccardo Rosati

*Proceedings of the Eighteenth International Joint Conference on Artificial Intelligence*, pages 16-20.

## Abstract

In this paper we address the problem of query answering and rewriting in global-as-view data integration systems, when key and inclusion dependencies are expressed on the global integration 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.