支持更新的XML编码方案

为解决XML数据更新时变更相应的子树编码导致的低效更新问题,以及插入结点过多而预留的编码空间不足造成的溢出问题,分析相关编码低效的原因,提出了一种支持XML文档更新的编码方案.采用该编码,XML文档树中现有结点的编码不受插入或删除操作的影响,避免了二次编码,降低了空间成本,采用编码对应表替代了原Dewey编码中各层之间的“.”分隔符,缩短了编码长度,并给出了基于该编码的XPath查询轴的判别方法,可快速判断结点间的结构关系.理论分析和实验结果表明了该编码方案的准确性和有效性.

XML coding scheme of supporting updates

To effectively solve poor efficiency update problem owing to recoding when update operation is done and resolve overflow problem because of insufficient reserve space when excess nodes are inserted.By analyzing the relevant reasons for poor efficiency,a XML coding scheme is presented,which supports update operation.When XML update operations are executed,recoding is avoided and space costs are reduced with the coding scheme.The corresponding table is adopted to replace the dot separator of each layer,then the length of coding is shorten accordingly.Based on the coding scheme,the XPath query method is proposed and the structural relation of nodes can be judged quickly.Theoretical analysis and experimental results show the accuracy and efficiency of the proposed coding scheme.