Query evaluation using overlapping views: completeness and efficiency

We study the problem of finding efficient equivalent viewbased rewritings of relational queries, focusing on query optimization using materialized views under the assumption that base relations cannot contain duplicate tuples. A lot of work in the literature addresses the problems of answering queries using views and query optimization. However, most of it proposes solutions for special cases, such as for conjunctive queries (CQs) or for aggregate queries only. In addition, most of it addresses the problems separately under set or bag-set semantics for query evaluation, and some of it proposes heuristics without formal proofs for completeness or soundness. In this paper we look at the two problems by considering CQ/A queries -- that is, both pure conjunctive and aggregate queries, with aggregation functions SUM, COUNT, MIN, and MAX; the DISTINCT keyword in (SQL versions of) our queries is also allowed. We build on past work to provide algorithms that handle this general setting. This ...

• Type: Conference
• Year: 2006
• Where: SIGMOD
• Authors: Gang Gou, Maxim Kormilitsin, Rada Chirkova
• Keywords: Aggregate Queries, CQ/A Queries, Database, SIGMOD 2006, View-based Query Rewritings