【摘要】 对有序XML文档树进行编码,不需要访问XML原始文件就能够实现对XML数据的管理,提高了XML管理系统的效率。针对查询提出的编码方案具有很高的查询性能,但更新效率很低。为提高更新性能而设计的方案存在查询效率低或者编码空间大等问题。为了在提高更新XML文档效率的同时不对查询性能和编码空间产生负面影响,提出了一种新的编码方法VEMBP(Vector Encoding Method Based of Prime),该方法利用向量表示有序XML节点之间的顺序关系,采用素数表示有序XML文档节点之间的结构信息;并设计了一种算法来实现在没有牺牲查询性能的前提下完全避免更新过程中的二次编码和重新计算,降低了更新代价,同时编码空间也得到了控制。实验结果显示,VEMBP具有较好的查询和更新性能。更多还原

【Abstract】 In order to improve the efficiency of the XML management system,some labeling schemas for the orderly XML tree were put forward,which realize processing of XML data under the condition of no need to access the original XML tree.The proposed labeling schemas for query have higher query performance,but the updating performance is poorer.Some novel labeling schemas designed for updating permance sacrifice query efficiency and possesse larger labeling space.For higher updating efficiency and smaller labeling space at the same time no reducing query efficiency,a novel labeling schema called VEMBP(Vector Encoding Method Based of Prime)was proposed,in which vector indicates order relation and a prime indicates structure relation between nodes in XML tree,and then an algorithm was designed which realizes updating in the cases no sacrificing query efficiency and completely avoiding secondary coding.Meanwhile labeling space is also under control.The experimental results show that VEMBP processes better on updating efficiency without sacrificing query performance.更多还原