A methodology for coupling fragments of XPath with structural indexes for XML documents

Supporting efficient access to XML data using XPath [3] continues to be an important research problem [6, 12]. XPath queries are used to specify nodelabeled trees which match portions of the hierarchical XML data. In XPath query evaluation, indices similar to those used in relational database systems - namely, value indices on tags and text values - are first used, together with structural join algorithms [1, 2, 19]. This approach turns out to be simple and efficient. However, the structural containment relationships native to XML data are not directly captured by value indices