Processing XML Queries with Structural and Full-Text Constraints

摘要

Efficient query processing on XML data is an important task for querying the data web. In this paper, we consider the XML query which can be represented as a query tree with twig patterns, and also consists of complex full-text constraints. Two approaches are proposed. The structure-first approach will first identify the elements which satisfy the tag constraint, and then process the full-text constraint on the terms represented within each element. The satisfied elements will be combined to meet the complete twig constraints. On the other hand, the keyword-first approach will first identify the elements which represent the required keywords, and then return the elements which satisfy the given full-text predicates and structural constraints. We demonstrate, via an extensive experimental study, that the two approaches have their own merits.