Efficient Evaluation of XML Twig Queries

With rapid acceptance of XML technologies, efficient query processing is a critical issue for XML repositories. In this paper, we consider the XML query which can be represented as a query tree with twig patterns. The proposed approach will first quickly retrieve data satisfying fragment paths which consist of only the parent-child relationship, and deal with the ancestor-descendent constraint in the later gluing stage. This approach focuses on where the data need to be “glued” and thus is very efficient. We conduct several experiments to evaluate the performance of the proposed approach. The results show that our system is more efficient than the holistic approach.