An Efficient Implementation of a Flexible XPath Extension

Nieves Brisaboa, Ana Cerdeira, Gonzalo Navarro, and Gabriella Pasi

In this paper we present an efficient implementation of different flexible queries (that constitute an extension of the XPath query language) to be executed on XML documents represented by using an interesting structure we call XML Wavelet Tree (XWT). A XWT represents the XML document compressed by using only about 35% of its original size, but it also provides some implicit self-indexing features that help to obtain not only efficient implementations of standard XPath queries, but also of extended ones. This is shown based on the implementation of the flexible structure based constraints, below and near.