A Study Of Coding Index Based On Schema

With its rapid development, the Internet has been an indispensable part of social life of the world people today. XML, with the advantage of a fine extensible capacity and easy to handle, has become a dominant standard for exchanging and representing information on the Internet. As XML is now being used more and more widely, optimization of XML inquiry schema has been one of the most concerned aspects of study. To build an index is a good way to fasten the query speed. However, there are still some problems with the index schema of XML, such as the lower efficiency of query and dynamic renewal, the high cost of nodes link. This paper attempts to design a different XNL index schema in the hope of improving the query efficiency of XML.This paper makes a fundamental study and analysis on the existing XML index technology and XML data structure, its inquiry language and coding method, and their effects on the index inquiry efficiency. The paper goes on to propose an XML Node Index (XNI) on the base of Schema. This index can effectively reduce times of node-handling, support complex inquiry path and dynamic renewal.The major work of this paper shows in following aspects:1. To improve Dewey coding(PDC) by combining the ideas of node-coding and path-coding, this paper proposes a new Path-Dewey Coding, PDC so as to realize the linking and matching of the branch paths in XML file.2. Referring to XML index method, after studying, analyzing and summing up its merits and demerits, this paper proposes an XML Node Index—XNI on the basis of Schema. This index can speed up inquiry by making use of XML format, coding Schema and XML individually, and applying PDC into XML coding.3. In accordance with the index structure, this paper devises a new path diving method, that is, to divine the complicated path divining into predicate nodes and target path. By using the structure chart, it enhances the query efficiency of predicate nodes, thus to enhance the path query efficiency.4. Node-coding index system is devised to prove the feasibility of the index proposed. Experimental results show that the index improves query efficiency.