The Research Of Heterogeneous Database Technology Based On XML In Distance Education

With the rapidly development of the Internet, distance education as one brand new teaching model approached. In order to rationally utilize the mass resource about distance education that were rushed out the network, but not to waste them, chiefly we should conform the data resource. Here we subject to go about heterogeneous data integration.The XML is the description standard due to it's special, such as platform-independent, extensibility, alternation and semantic relation. The common model of heterogeneous data based on XML carry out the data description and data exchange in heterogeneous database, which solve the problem existed in tradition data integration, such as federation query optimize. Using the technology of the XML, we also set up the diversion relation in heterogeneous database.From the research background of distance education, the thesis focuses on relevant theories and technologies of heterogeneous data, and analyses the current data integration approaches. At the mean time the paper discusses many research projects about heterogeneous data integration, and builds a common model of heterogeneous database integration via the technology of middleware. The thesis also evolutionarily brings up the concept of virtual-database and middleware-server. The virtual database integration uses XML Schema as the common data model, and presents Xquery decomposition algorithm and supports the integration of relational sources, XML sources through the Query decomposition and Schema mapping. At last combining the application of distance education system, and using the system architecture, system frame and processing procedure of B/S model design, the application of XML-based data integration system and technologies are implemented and performed.