基于相容关系的XML索引机制

随着XML逐渐成为Internet数据表示与数据交换的标准,存储与查询XML数据变得日益重要.由于传统方法无法适应XML数据新的需求,使得XML索引成为一个挑战性的课题.到目前为止,已经出现了不少针对XML数据的索引方法.然而,在处理基于相对路径的查询上,缺少有效的解决办法.本文提出了一种基于相容关系的索引模式,结合XML文档拓扑结构的自身特点,能够有效地处理基于相对路径的查询.这种模式的主要特点包括:(1)利用XML数据的拓扑结构而不是XML文档的模式(DTD或XML Schema)来进行相对路径到绝对路径的转换;(2)对拓扑结构进行基于相容关系的数字方式编码,能够快速确定对应结点的依赖关系.实验证明这种方法在处理基于规则路径表示(尤其是相对路径)的XML查询时具有更高的效率.

Containment Based XML Indexing

With the advent of XML as a standard for data representation and exchange on the Internet,storing and querying XML data becomes more and more important.This poses a new challenge concerning indexing and searching XML data,because conventional approaches no longer apply to XML data.A variety of novel indexing techniques for efficiently retrieving the results have been proposed in the recent literature.However,relative path based query still needs to be more efficient.A containment based indexing scheme for XML data is proposed,which makes full use of the topological structure of the XML documents and can be more efficient to deal with relative paths than previous methods.The key properties of the scheme are as follows:(1)Transform relative paths to absolute paths by using the topological structure of the XML documents instead of DTD or XML Schema;(2)Apply a numbering scheme to the topological structure,which can quickly determine the ancestor descendant relationship between elements in the hierarchy.Experimental results from the prototype system implementation shows that the scheme can be used to process XML queries with regular path expressions(especially relative paths)faster than previous approaches.