Abstract: With the development of Internet and the constantly increasing scale of XML data, how to query the XML data exactly and efficiently becomes a hot issue. At present, there are many algorithms for twig pattern matching, but they dont have good method to solve the twigs which have parent-child edges. The new algorithm called PCTwig was proposed for this problem, which was based on the ordered pair. The twigs were queried through setting the ordered pair of parent-child relationship on query tree and document tree. In query process, it can avoid useless intermediate result and merge operation. The experiment shows the effectiveness of the approach.

Key words: XML document, XPath, twig pattern matching, ordered pair, parent-child relationship

摘要： 随着Internet的发展和网上XML数据规模的与日剧增，如何准确、高效地查询XML数据已经成为研究的热点问题。目前，已经提出了很多小枝模式匹配算法，但没有解决含有父子边的小枝模式查询。针对该问题，提出了一种基于有序对的新算法PCTwig，通过在查询树和文档树上分别建立父子关系的有序对来进行查询。查询过程中避免了产生中间结果，也不需要进行归并操作，实验证明该算法是有效的。

关键词: XML文档, XPath, 小枝模式匹配, 有序对, 父子关系