基于自动机XML正则路径表达式查询研究

Research of XML regular path expression query based on automaton

基于自动机正则路径表达式查询技术是半结构化数据模式下XML查询研究领域颇有价值的方法。许多研究方法对含有"//"操作符和"*"通配符复杂正则路径重写都会产生大量中间路径。设计了处理XML正则路径查询高效方法———CSAS,利用对象交换模型(OEM)作为XML数据模型,有限自动机作为查询模型,提出裁剪XMLSchema转化的自动机片断作为重写自动机来重写"//"和"*"符号的重写技术;利用剪枝技术、谓词处理后移策略实现查询优化。实验证明,CSAS方法是一种高效的XML正则路径表达式查询方法。

Currently, the query technique that supports finite automaton Regular Path Expression （ RPE） is valuable in the research area of eXtensible Markup Language （ XML） query in semi-structured data mode. Lots of middle paths were produced by many research methods that rewrite complex RPE with ＂ //＂ symbol and ＂＊ ＂ wildcard. The authors designed an efficient XML RPE query disposing method—Cutting Schema Automaton Snippet （ CSAS） using Object Exchange Model （ OEM） as XML data model and finite automaton as query model, put forward rewriting technology that cut out snippet of XML Schema transforming into automaton to rewrite ＂ / /＂ and ＂＊ ＂, the query optimization was realized by Pruning techniques and predication back strategy. The experimental results prove that CSAS is an effect query method of RPE.