Xml-based Heterogeneous Database Access Middleware

As the development of the computer network technology, business enterprise data integration from business enterprise inner part integration headed for the integration of business enterprise, and more and more companies need to issue and exchange the inner data, which need to access the heterogeneous databases inevitably. That is why the uniform and transparent access to heterogeneous databases becomes a problem need to discuss deeply.This paper makes use of the database middleware technology to resolve the problem of the access to the heterogeneous databases. First researched the essential reason of database middleware in the application of heterogeneous integration, introduced the theory, characteristics and common technique of database middleware. Then analyzed CORBA technique and XML technique, combined the advantage of both XML and CORBA, designed a new common heterogeneous databases access middleware according to the thought of database, and gibed the detailed design project and the progress of implement.In this project, we use the XML documents to save the information of metadata, including the global tables, local tables and the particular information of the mapping between global tables and local tables. We use CORBA client to receive the requests of the business operation system, spilt the request into sub requests and analyses the sub requests according to the directions of the metadata. Then call the object in the CORBA server, at last combine the result which returned for CORBA server and send it back to the business operation system. The major work in the CORBA server is accessing the specifically databases and transferring the record set to the XML format. This system is based on the CORBA distributed platform, use the XML as the common data modal ,use the technology of JDOM, JDBC, database connection pool and the buffering pool. This database middleware shield the heterogeneous of the database operation, provide the users with uniform results, and this system has the advantage in transportability, plus and play and distribute computing.