Evaluation of Twig Pattern Queries Based on Ordered Tree Matching

Abstract

In this paper, we study the evaluation of twig pattern queries based on the ordered tree matching. Different from the query evaluation based on the unordered tree matching, by which the order between siblings is not significant, the ordered tree matching takes the order between siblings into account and is useful for some applications such as tree-bank query evaluation. A new algorithm for this problem is proposed, which runs in O(|T|¿|Q|) time, where T and Q are a document tree and a twig pattern, respectively. Especially, our algorithm can be very easily adapted into an indexing environment. Experiments have been conducted to compare ours and some well-known methods, which demonstrates that our method is effective, scalable, and efficient in evaluating twig pattern queries.