Research On XML Data Storing And Retriving

XML has become the universal format for the representation, exchange and storage of information over the Internet. To realize XML's potentials, its effective storage is one of the important technology issues we consider.After the storage problem is proposed, this article analyzes the current research. Because of the general representation ability of XML format, its property of semistructure, its schema or data/document property and requirement of the different XML's application, the storage problem is becoming more complicated. There are three alternative schemas for storing XML data nowadays: one is to store XML documents as ASCII files in the operating file system; another is to use a commercial database management system to store; the third is to develop a special storage format and supporting software to store XML data.Following that, this article describes five different approaches in details for storing XML documents and analyzes the performance of each schema. Because of the maturity of relation database, storing XML in RDB is a good choice. Based on the DOM, this article surveys two kinds of uncomplicated and typical relation approaches for XML storage, and does experiment to analyze their performance. The next step is to study the transformation algorithm from XML to RDB, this article uses an improved CPI algorithm, achieves Constraint-preserving transformation from XML to Relational schema. This article has also theoretically constructed a multi-agent based E-commerce system, specifies the requirements needed for communication among agents, selects XML as the message format and mainly focuses on studying the approach of transformation data stored in relational database to XML data. Moreover, it partially formalizes the algorithm and implements it.In the last, research results of this dissertation are summarized, and some directions for further research are also provided.