基于模式的XML路径表达式查询处理技术

为了有效地利用文档类型定义(DTD)中的路径信息、减少结构连接次数,使用二元前缀码对DTD的元素或属性编码,并将DTD编码引入到XML节点编码中.在此基础上,将路径表达式查询分解成若干查询片段,利用二元前缀码的"位"操作高效地计算每个查询片段的结果,最后使用结构连接将这些查询结果组合起来.实验结果表明该方法是正确的和高效的.

Query processing strategy of XML path expression based on schema

To make effective use of path information and reduce the number of joint operations, the authors labeled each element or attribute in DTD with a binary prefix code, and introduced the DTD code into the numbering scheme for XML documents. Based on this, path expression queries were decomposed into a series of query fragments. Then these query fragments were efficiently evaluated by using a bit-wise operation of the binary prefix codes. Finally, the results of the query fragments were composed by structural joint. The experimental results show that the proposed approach is effective and efficient.