Research On Update-Supporting XML Data Encoding Methods

According with the fast development of computer and network techniques, Internet has became the important source of global information transmission and communion, for that reason that how to use the large mount of information is one of the urgent problems that we need to resolve immediately today. Admittedly, corporations and individuals exchange their information and data by Internet more and more frequently, however, due to their different render pattern of their data, the traditional data pattern is not fit for consumers' requirements to represent their data Then there need a unified data pattern to render consumers' information, which could widely accepted by Internet users. At the same time, the appearance of XML gains a pervasive attention, and fast develops with the network' application, then final becomes criterions of data represent and exchange. Thus, due to the pervasive use of XML, an effective way of storing and inquiring XML data, especially in the particular code schema, becomes one of the research focuses of XML field.There are two main ways to represent XML document tree currently: encoding based on interzone and encoding based on path. The first method - encoding based on interzone, utilizes the characteristic of order of XML documents, coded the node by its alphabetic position in the original XML document. While the second way -encoding based on path, uses the nested traitor of XML documents, gave a code of each node which could arrived from the root node in every path. However, until now the proposed encoding methods of XML data are all not well supporting the dynamic update of XML data, and this paper does do the study in this aspect.Based on the analysis of the comparison of the existing XML data encoding method, a new method which supports dynamical update is proposed here. The encoding method can rapidly and accurately judge the parent-child ancestor/descendant and sibling relationships between any two nodes of the XML Document tree; and we adopt the variable expanded order to support update of XML data and so effectively reduce the secondary XML encoding rate. The main work of this paper is as follows:(1) After analysis and comparison ,summing up the inadequacy of existing coding methods(region encoding,prefix encoding,bit-vector encoding and PBiTree encoding): not well supporting the dynamic update of XML document tree.(2) A new method which supports dynamical update is proposed. Use extended order between brother nodes.More extended serial number between the brother nodes is set aside in the higher level. Each node saves the incremental value of order. With the XML document updates increase, the secondary XML encoding rate is reduced.(3) This paper describes the process of encoding and encoding algorithm is also given; and the encoding characteristics and code update algorithm is described in detail, too. The update of nodes after inserting new nodes is also discussed with examples in different category.(4) Through the experiment, we do some comparative analysis on timeperformance, space performance, and the second encoding rate performance between the new encoding method and the existing encoding method.