Complex queries in XML-GL
Stefano Ceri, Sara Comai, Ernesto Damiani, Piero Fraternali, Letizia Tanca · 2000
In this paper we describe the advanced features of XML-GL, a graphical query language over XML data which enables the retrieval and restructuring of XML documents in a simple and intuitive way.After a summary of the basic features on the language, we focus on complex queries, whose expressive power subsumes some well-known relational operations (e.g.union, difference, cartesian product) but goes well beyond from these relatively simple operators.