一种降低XML文档更新代价的扩展Dewey编码方案  

Extended Dewey Encoding Scheme for Reducing Update Costs for XML Data

作　　者：杨小萍[1,2] 李德录[1] 周文勤[1] 

机构地区：[1]天水师范学院物理与信息科学学院,甘肃天水741000 [2]中山大学信息科学与技术学院,广东广州510275

出　　处：《沈阳师范大学学报（自然科学版）》2010年第2期214-217,共4页Journal of Shenyang Normal University:Natural Science Edition

基　　金：国家自然科学基金资助项目(60373081;60673135);广东省自然科学基金重点项目(04105503);广东省自然科学基金资助项目(5003348)

摘　　要：Dewey是一种主流的XML文档编码方法。在Dewey编码基础上进行了扩展,根据XML文档树中结点的位置特性与更新代价的相关性,提出了一种扩展的Dewey二元组编码方案,给出了明确的节点编码计算表达式,为每个结点预留了不同大小的编码空间,降低了XML文档树更新操作时需重新编码结点的代价。结点编码采用二元组形式,每个编码包含了该结点深度指标值,缩短了计算结点间结构关系的时间。充分的试验结果证明,编码方案查询速度快,插入更新性能优异。因此,编码方法在不提高编码效率和不损失查询速度的前提下,可以较好地解决更新操作所造成的节点重新编码的问题,是一种较好的前缀编码。Dewey is a mainstream XML document encoding method.This paper,extending on the basis of Dewey coding,put forward an extended Dewey 2-tuple coding scheme in light with the correlation between the position characteristic and the updating cost of the nodes on XML document trees.It reserves different coding space for each node and decreases the number of nodes needed to be recoded when XML document trees updated.Adopting the mode of 2-tuple coding,each node contains the depth indicator value of itself,thus the calculating time on the structure relationship between nodes and node coding is reduced.The full test results show that the speed of this coding scheme query is fast with high insert update performance.Accordingly,the encoding method can solve the problem of the node to re-encode caused by the update operation under the premise of not improving efficiency of encoding and without the loss of the speed of query.It is a good prefix encoding.

关 键 词：XML DEWEY编码 预留空间 更新代价 

分 类 号：TP311[自动化与计算机技术—计算机软件与理论]