时态XML索引技术

首先通过讨论时态XML查询数据模型TXQDM,提出了基于结点有效时间的前缀编码方案.以此为基础,引入TXQDM结点间的基于时态连通的等价关系和基于时态包含的拟序关系,建立了时态XML索引数据模型TXIDM,该模型的基本特征是具有二重嵌套的索引框架,适合于TXQDM这种不规则的具有较大随意性的树形结构情形.其次,在TXIDM框架内,讨论了相应时态查询算法,其中包括基于时态的路径查询和值查询,同时,还讨论了时态索引更新算法,其中包括插入和修改算法.最后,对于文中提出的模型TXIDM和时态索引操作算法进行了性能分析且设计了相应模拟实验.实验结果表明,基于TXIDM的时态查询与更新算法是可行的和有效的.

Technology on Temporal XML Indexing

This paper is devoted to the technique and implementation of temporal XML indexing. Firstly,this paper proposes the schema of prefix-code based on the valid time of nodes,and intro- duces the temporal equivalence and temporal quasi-order relationships which result from the tem- poral connection and inclusion on the set of the valid time periods of all temporal nodes.Using these relationships,the paper builds the index model of temporal XML data,that is TXIDM,and the TXIDM has a characteristic of the re-nesting structure which may be more suitable to the ran- dom tree-type structure of the temporal XML data.Secondly,the paper discusses the index algo- rithm on temporal query(values query and path query)and temporal update(inserting and modi- fication)and these two may be described uniformly as they are all based on the properties of the relationships especially the quasi-order.Finally,the paper completes the analysis of capability and the designing of the experimental simulation for the model and algorithm,and the experiment results suggest that the operation on temporal update and query are feasible and efficient.