A theoretic framework for answering XPath queries using views

Abstract

Query rewriting has many applications, such as data caching, query optimization, schema integration, etc. This issue has been studied extensively for relational databases and, as a result, the technology is maturing. For XML data, however, it is still at the developing stage. Several works have studied this issue for XML documents recently. They are mostly application-specific, being that they address the issues of query rewriting in a specific domain, and develop methods to meet the specific requirements. In this paper, we study this issue in a general setting, and concentrate on the correctness requirement. Our approach is based on the concept of query containment for XPath queries, and address the question of how that concept can be adopted to develop solutions to query re-writing problem. We study various conditions under which the efficiencies and applicability can trade each other at different levels, and introduce algorithms accordingly. © Springer-Verlag Berlin Heidelberg 2005.