Modeling and querying XML-data

The authors discuss data models and query languages for XML data. They propose a data model, called XDT, which takes care of the structural features of XML data. XDT represents XML data by means of labeled oriented graphs. With respect to other previously proposed models, XDT handles links definable in both XML and XLL. Queries are made through an SQL-like language which uses weighted path queries, i.e. path queries based on weighted regular languages and gives, as a result, a set of pairs (node/weight) where node is an `element´ of an XML document and weight gives information about the relevance of the node