XIRQL: An XML query language based on information retrieval concepts

XIRQL ("circle") is an XML query language that incorporates imprecision and vagueness for both structural and content-oriented query conditions. The corresponding uncertainty is handled by a consistent probabilistic model. The core features of XIRQL are ( 1) document ranking based on index term weighting, (2) specificity-oriented search for retrieving the most relevant parts of documents, (3) datatypes with vague predicates for dealing with specific types of content and (4) structural vagueness for vague interpretation of structural query conditions. A XIRQL database may contain several classes of documents, where all documents in a class conform to the same DTD; links between documents also are supported. XIRQL queries are translated into a path algebra, which can be processed by our HyREX retrieval engine.