基于XML路径表达式优化及其查询和过滤计算方法研究

Studies on the Query Processing Optimization and Calculation Method of Query and Filtering Based on XML

主要对XML路径表达式的优化、查询和过滤算法三个方面进行了研究.运用补路径和缩短路径方法对路径表达式进行优化.通过对路径表达式进行优化来提高查询速度的方法称为路径缩短策略.用简单的路径表达式来代替用户所建立的复杂度表达式的方法称作补路径.用Xpath语言对XML查询进行处理,并对Xpath表达式以及查询处理进行了研究,Xpath查询处理主要通过对XPE-Tree进行匹配以及两次路径连接运算来实现查询处理.XML的过滤系统通过路径表达式来进行模式和内容匹配,在用户信息输入系统之后,生成过滤引擎,过滤引擎与数据流进行匹配,输出用户感兴趣的信息,以此来完成过滤过程.

The optimization of XML path expression,algorithms of querying and filtering were investigated.The fill path and the path shorten were used to optimize the path expression.The method that the path expression was optimized to improve query method＇s speed was called path shorten strategy.The method that a simple path expression was used in full to replace the complexity of expression was called full path.In XML query processing,Xpath was used as a processing language to deal with XML query processing.The Xpath expressions and query processing were also studied.XPE-Tree was used to match in Xpath query processing,and twice path concatenation was used to achieve the query processing.The path XML expression was used in the filtration system to match the pattern and content.After the user information was input to system,filtering engine has been generated,then,the engine of the filter and the data stream were matched,the information that the user was interested was output,the filtration process has been completed.