Answering Queries Using Views
Alon Y. Levy, Alberto O. Mendelzon, Yehoshua Sagiv, Divesh Srivastava · The MIT Press eBooks · 1999
) Alon Y. Levy AT&T Bell Laboratories [email protected] Alberto O. Mendelzon University of Toronto [email protected] Yehoshua Sagiv y Hebrew University, Jerusalem [email protected] Divesh Srivastava AT&T Bell Laboratories [email protected] Abstract We consider the problem of computing answers to queries by using materialized views. Aside from its potential in optimizing query evaluation, the problem also arises in applications such as Global Information Systems, Mobile Computing and maintaining physical data independence. We consider the problem of finding a rewriting of a query that uses the materialized views, the problem of finding minimal rewritings, and finding complete rewritings (i.e., rewritings that use only the views). We show that all the possible rewritings can be obtained by considering containment mappings from the views to the query, and that the problems we consider are NP-complete when both the query and the views are conjunctive and don't in...