Xml-based Integration Of Heterogeneous Database Study

For a long time ,there are large quantities of isomerous database in the network. Their isomerism shows in many aspects such as different database type, different data representations, different DBMS for supporting database. With the development of business cooperation and the electronic governmental affairs, many information systems need to access the data in the isomerous database. Therefore, a new system framework is needed to integrate the information in multiple isomerous database. The advantages of the XML(Extensible Markup Language) such as irrelevancy with the platform,easy expansion, good interactivity, good semantic quality and formatting ability, can make it describe the relational database easily and act as a bridge in the conversion process of these relational database.The key point that exploits XML to establish the isomerous database integration model, is to set up the conversion relationship between XML and database. At present, there are two universal conversion methods: one is based on the template; the other is based on model. Both of them have some limitations. The former one only sustain one way mapping from the relational database to XML, and the latter one has some limitations to XML's structure.Based on the research into the existing mapping algorithms and models, the traditional data integration techniques are compared and analyzed in this paper. With XML as the common model, the uniform conversion instrument of isomerous database is set up through the reversible bidirectional conversion between relational database and XML. The conversion process can retain the relational database's entity integrity constraint referential integrity constraint and most of customing integrity constraint.The algorithm that convert the XML Mode to Relational Mode is realized in this paper. Finally two application modules are established for the conversion of the two modes, and the uniform conversion instrument of isomerous database is developed. This data conversion instrument can realize the mode conversion and data transference among different isomerous database better, and realize the conversion process' automatization and independence of database types. The algorithm of conversion between the Relational Mode and the XML Mode, which enables an enterprise to issue data on Internet or Intranet conveniently, provides the enterprise with the technical basis for the integration of data source on a higher level.