XyView: Universal Relations Revisited

We present XyView, a practical solu- tion for fast development of user- (web forms) and machine-oriented applications (web services) over a repository of het- erogeneous schema-free XML documents. XyView provides the means to view such a repository as an array that can be queried using a QBE-like interface or through sim- ple selection/projection queries. It ex- tends the concept of universal relations in mainly two ways: (i) the input is not a re- lational schema but a potentially large set of XML data guides; (ii) the view is not dened explicitely by a unique query but implicitly by various mappings so as to avoid data loss and duplicates generated by joins. Developed on top of the Xyleme content management system, XyView can easily be adapted to any system support- ing XQuery.