Research On Updating Code Schema And Index Techniques For XML Data

XML has become a new standard format to express and exchange data in the Internet.In recent years,a large number of XML data has emergenced.In order to process the data in the XML document,expert and researcher have done positive and depth study on encoding, indexing,querying and so on,a large number of coding schemes and indexing techniques have been proposed.It's expensive to re-code and re-index when the XML data updated frequently,which affected the efficiency seriously.Because these coding schemes and indexing techniques couldn't support dynamical updating XML data.In this paper,we have researched usefully on XML coding schemes and indexing techniques,which efficiently supported that XML data dynamically update.This paper analysed encoding technology of XML documents and proposed a Coding Scheme of Supporting XML data dynamical Updating(CSSU).CSSU code scheme encodes the node with letters, digitals and underlines while those traditional coding schemes encode the node with digital.To insert and delete nodes coding,CSSU does not affect the other nodes coding and needn't re-code at all.It exists infinite coding space between any two codings and would not appear the problems that LI-MOON coding reserved coding space and would run out of coding space and the size is not easy to determine.The CSSU coding efficiency can multiply improve when the XML data updates frequently.A new index DUIX based on CSSU coding was proposed in this paper,which supported dynamical updating XML data.DUIX could quickly determine the structure relations by coding between any two nodes,and preserve detailed child-parent information,and cluster nodes of the same lable path.DUIX supported branch query,which no longer relied on XML documents,and it got all nodes by visiting a path,and skipped abundant of irrelevant nodes.It's more efficiency than other index techniques.Finally,this paper did a large number of experiments to compare CSSU and DUIX with index based Ctree and XISS.The results demonstrated that the CSSU and DUIX were effective.