| Along with the Internet development, enterprise's practical application will possibly meet the problem that the data distributes in the different places, moreover these data are heterogeneous. Practical application need to carry on the effective integration to these distributional heterogeneous data. Simultaneously, original data had already developed application system in these data foundation accordingly. This paper developed the data integration not to be able to affect the existing system.According to the characteristics and requirements of distributed heterogeneous data integration, this paper designs and implements a data integration middleware. To set up a public integrated environment under distributed environment,which shields all differences in aspects of data source including the platform, system environment and internal data structure. It provides a unified and transparent interface for users to implement the accession and publication of relative data among heterogeneous data sources. The following is the main study of the content:①OGSA-DAI will use local data sources into a Web services package in order to provide unified approach to data access services, shielding heterogeneous data access method in the difference.②Release services to use to create database schema from the global to the local database schema mapping, shielding semantically heterogeneous data differences.③The use of directory services manage the database metadatas, table metadatas, fields metadata, the database units metadata and services metadata, services virtual field metadata, the actual field service metadata, users can easily query, add and remove.④The definition of the global query language , the design of the global query language to relation and XML database query language conversion algorithm and the result of the conversion algorithm.The middleware is applied in student course , it can successfully integrate some heterogeneous datas and provide a unified and transparent interface for users. |
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