Chapter

Database and Expert Systems Applications

Volume 6861 of the series Lecture Notes in Computer Science pp 1-16

On Equivalence and Rewriting of XPath Queries Using Views under DTD Constraints

  • Pantelis AravogliadisAffiliated withDepartment of Informatics, Athens University of Economics and Business
  • , Vasilis VassalosAffiliated withDepartment of Informatics, Athens University of Economics and Business

Abstract

It has long been recognized that query rewriting techniques are important tools for query optimization and semantic caching and are at the heart of data integration systems. In particular, the problem of rewriting queries using view definitions has received a lot of attention in these contexts. At the same time, the XPath language has become very popular for processing XML data, and there is much recent progress in semantic XPath optimization problems, such as XPath containment, and, more recently, XPath rewriting using views. In this paper we address the open problems of finding equivalent query rewritings using views for XPath queries and views that include the child, predicate and wildcard features (i.e., they are in XP(/, [], *)) under DTD constraints. In the process, we also develop novel containment tests for queries in XP(/,[],*) under DTD constraints.

Keywords

XML data XPath processing query rewriting using views