【摘要】 分析了XML模式与XML文档之间的关系以及XML查询的特点,提出了一种基于复杂模式索引的XML查询优化方法。该方法对XML模式中的节点建立索引,查询时考虑XML模式中带有环的情况。首先对查询树进行去除重复元素的预处理,并将查询树分解成主路径和分支路径;然后利用索引查找潜在目标节点的XML模式编号;最后在XML文档中对对应节点进行筛选,找到目标节点。该方法可以减少连接操作的次数,提高查询操作的效率,能处理较复杂的XML模式。更多还原

【Abstract】 The paper analyzed XML query and the relationship between XML scheme and XML documents.Proposed a complicated scheme index-based XML query optimization method.Indexed parent/child node and ancestor/descendant node,took the XML scheme with loop into account.Firstly pretreated the query tree with repetitive labels,then decomposed the query tree into main path and branch path.When executed the query,applied the indexes to accelerate the query calculation.This method would reduce greatly number of join,improve the efficiency of query.It could process the complicated scheme.The result of the experiments indicate that the performance of this method is excellent.更多还原