RWTH Aachen University
This is the first and preliminary study on answering queries using views in a probabilistic XML (eXtensible Markup Language) setting. The authors formalize the problem and study it under the two possible semantics for XML query results: with node identifiers and in their absence. Accordingly, they consider rewrite plans that can exploit a single view, by means of compensation, and plans that can use multiple views, by means of intersection. Since in probabilistic settings queries return answers with probabilities, the problem of rewriting goes beyond the classical one of retrieving answers from views.