Web Services And XML-based Digital Library Research On Data Integration In Heterogeneous Databases

With the rapid development of information technology, especially in the fields of computer and internet system, various kinds of data resources emerge in endlessly. Different kinds of database systems and data platforms boost the development of data library. As far as the user is concerned, it will be difficult or inconvenient for most of them to obtain what they really need by the means of searching and visiting different data resources and inquire system and being familiar with its searching usage and display format.In order to make better use of abundant resources of data library and enhance its usage rate and efficiency, it is compulsory to establish a uniform integrated platform of database system with the aim of solving the problem of heterogeneous databases integration and realizing the data share between different data base system. By means of the conversion of the different structured data form integration, transmission, which give readers a unified form of the different types of digital resources and help them achieve the uniform inquiry and visit.At present, on the problem of heterogeneous databases integration, a great deal of research is aiming at application database system at home and abroad, such as enterprise heterogeneous information resource integration research and student's data center integration research, both aiming at realizing the date sharing between the different data base. In the field of digital library, more researches aim at the problem concerning integration of library automatic management system and integrated inquiry and pay little attention to the research on data resource integration. In view of this situation, the research put emphasis on heterogeneous databases integration of digital library based on Web Services and XML(Extensible Markup Language),which is dedicated to realizing the inquiry and visit of the various digital resources of the digital library.Firstly, the research analyses current way and operation principle of heterogeneous databases integration and introduces the related knowledge of XML and Web Services and its application in heterogeneous databases integration in detail. The research elaborates on the feasibility of realizing integrated visit of heterogeneous databases based on XML and Web services.Secondly, the research brings forward a three-layered model of realizing integrated visit of heterogeneous databases based on XML and Web services after a detailed discussion about the traits of heterogeneous database resource and digital resource structure to the digital library. A detailed design has been made from the angles of integration and conversion of heterogeneous digital resource and HTML(Hypertext Markup Language)browsing, including needs analysis, system analysis, the overall framework of system design, database design, schema integration analysis, the design of system features modular and the illustration of system workflow .Finally, on basis of the above research, a great deal of efforts are made to design and implement the heterogeneous integrated access to digital resources system modules, including the system database connection module, data transfer, implementation, heterogeneous resources, search, heterogeneous resources, conversion, heterogeneous storage resources, as well as resources for the conversion of HTML browser, and the design of a J2EE client interface for user access, and ultimately achieve the unification of heterogeneous digital resources retrieved visit.