Research And Implementation About Multi-tier Database Application System Based On Component Technology

Database technology is the basic technology of computer science. The application of database is always the highlight of computer application. People brought forward the concepts of File Server and Tow-layer Client/Server successively. These developing modes satisfied the needs of application in the certain period.With the development of the computer science, the scale of database is becoming bigger than ever. Because these traditional developing modes have some inherent defects such as not easy to maintain, lower efficiency and not easy to use the codes repeatedly, the traditional modes of database application cannot supply the demand now. To solve these problems, the mode of database application development always changes with the problem. With the developing of computer science, File server mode became Two-layer Client/Server mode, and now, Two-layer Client/Server mode becomes Distributed Multi-tier Client/Server mode. Distributed software is the inevitable direction of the developing. At the same time, with the scale of information to be solved is becoming bigger, Distributed Multi-Tier Database System is becoming the inevitable result of database development. Its basic idea is to separate the user intertace from the logic of enterprise, and divide the information system into interface, function and data. These three parts are located in different flat of hardware to enhance the extension of application system. With the appearance of Component Object Mode, the realization of multi-tier application system is possible. Middleware is such a software that between application system and system software. Middleware play a key role in the process of construct multi-tier application. It uses basic service(function) that system software offers, links up different part of application software or different application in the network to achieve the aims such as share the resources and share the function. Middleware locate on the operation system of application server, manages the computer resources and network communications.The article discusses several kinds of developing mode of database application development, and analyses the important position of component technology in multi-layer application at length, and emphasizes how to use COM+ component as themiddleware to construct multi-layer application. Finally, the article discusses the realizing of multi-tier system in co-ordination with the example.