GXQuery: Extending XQuery for Querying Graph-structured XML Data

XML data can be naturally modeled as a graph. Existing query languages to XML can only express queries of matching XML document with a tree-structured schema with structural and value constraints without the consideration of graph features. The ability of such query languages cannot satisfy various requirements of querying graph-structured XML data. In this paper, GXQuery is presented as an extension of XQuery, an XML query language recommended byW3C, to expressmore flexible query on graph-structured XML. GXQuery expressions can match XML document with graph-structured schema with not only structural and value constraints, but also topological constraints.