Research And Implementation Of Heterogeneous Database Access Middleware Technology Based On XML

Due to the need of self-requirement, related application system has been established by Enterprise's business department,on account of lacking unified planning, business standard and other objective reasons,mang systems are separated from each other,the phenomena of information island is serious.As the rapid development of techniques and frequent cooperation of each business department,it's more and more importmant that these isolated systems need to contacted organically and the sharing degree is eager to improved.So,how to make a uniform,transparent and convenient access to heterogeneous databases becomes a problem needed to be discussed urgently.This thesis makes use of the database middleware technology to resolve the problem of heterogeneous database access. First of all, it introduces the current solution to the interconnection of heterogeneous and the neccessity of the middleware in integrated heterogeneous, and then emphasize on the characteristics and common method of the heterogeneous database integration middleware. After that, it analyses the technology of XML and commonly used middleware in distributed object. On the basis of the analysis and comparison, it puts forward the advantages of Web Service used in heterogeneous database middleware and the combination of XML and Web Services in the middleware, According to the general ideal of database middleware, I designed a universal heterogeneous database access, at the same time provided the details of design and its implementation process.XML document is used to preserve the meta-data information,including the global table,the mapping of the global and local tabe and the web service registration information of the local table .The request module receives the information from the application, and according to the meta-data information, decomposes it into some service requests. After that the quote module finds the service information providers from the UDDI registration service center and sends it to the Web Service wrapper by putting them as a SOAP to query various heterogeneous database.And then, according to the service result module, the result will be transformed into a local XML document, then the information which is sent to the application layer is merged congruously with the information of the meta-data table by the merging module.This database middleware shields the heterogeneity of database operations, which provides users a unified access interface,and the same time implements the good features of loosely coupled,flexible,easy to expend and achieve the seamless integration of heterogeneous databases.