Design And Realization Of Heterogeneous Data Source Harmonization System Based On XML And MiddleWare

With the development of information technology, it has become more and more necessary to share, exchange, harmonize and reuse all kinds of knowledge in all areas. More and more users expect to access and deal with the data stored in heterogeneous sources of different network nodes. However, not all data are stored in the same database under the same operating system, and not all database systems have the same interface, which causes the big obstacle to data sharing.It has become necessary for digitization and network construction of library to meet the increasing needs of readers who are eager to acquire the knowledge from the Web. However, there are large quantity of data sources in the library, such as bibliography, electronic book, CD and so on. The data are stored and accessed in different way. It always needs users to retrieve them under the different system.In the research of digital development project of the university library-"OPAC Uniform Retrieve of the Bibliography and Electronic Resource", aiming at the character of heterogeneous data and combining XML with JAVA technology, the paper discusses, to some extent, the harmonization model of heterogeneous database based on XML and middleware.XML is an extensible and self-descriptive data format which can express all kinds of data. It solves the uniform interface problem and makes it easy to share and exchange the data from different database. JAVA is a real cross platform development environment and provides the XML supported interface. Middleware can reduce the correlation between components and data, improve the independence of the components and extend the area reused.This paper mainly discuss the following: firstly, the paper introduces the development of heterogeneous data harmonization, including some updated research production, and analyses the problem of uniform retrieve in the library; secondly, it introduces the technology and application of XML and middleware and discusses the feasibility of designing harmonization middleware based on XML; afterwards, the paper has a introduction of the XML global view construction and management. Based on the analysis of mapping between relational database and XML, the paper brings forward a mapping object model; next, the author designs a heterogeneous data harmonization middleware and analyzes the work theory of each component.At last, against the above discussions, we realize the OPAC uniform retrieve of bibliography and electronic resource using XML and JAVA under the Windows 2000 operating system.