XML Query Languages in Practice: An Evaluation

The popularity of XML as a data representation format has led to signi cant interest in querying XML documents. Although a \universal" query language is still being designed, two language proposals, XQL and XML-QL, are being implemented and applied. Experience with these early implementations and applications has been instructive in determining the requirements of an XML query language. In this paper, we discuss issues in attempting to query XML, analyze the strengths and weaknesses of current approaches, and propose a number of extensions. We hope that this will be helpful both in forming the upcoming XML Query language standard and in supplementing existing languages.