Optimized Query Rewriting for OWL 2 QL

Alexandros Chortaras, Despoina Trivela, Giorgos B. Stamou

Abstract: The OWL 2 QL profile has been designed to facilitate query answering via query rewriting. This paper presents an optimized query rewriting algorithm which takes advantage of the special characteristics of the query rewriting problem via first-order resolution in OWL 2 QL and computes efficiently the rewriting set of a user query, by avoiding blind and unnecessary inferences, as well as by reducing the need for extended subsumption checks. The evaluation shows that in several cases the algorithm achieves a significant improvement and better practical scalability if compared to other similar approaches.