Application of middleware in the three tier client/server database design methodology

With the popularity of personal computers and powerful workstations, today's users are no longer satisfied with the traditional data processing. They demand eagerly to putting up graphics on existing applications, putting a lot of pressure in system re-engineering. The Client/Server architecture is a less risky and less costly approach in adding a Graphical User Interface for users. The developer has to determine data and program logic distribution among client, middleware server, and the top-tier server. Middleware is a kind of software that links programs running on different platforms, transmitting messages and data. It plays an important role in 3-tier architecture. There are two types of middlewares: the first connects client programs to server programs, and the second provides data access connections to heterogeneous data sources. The developer also needs to separate on-line transaction processing, project-oriented data processing, and history data from each other. In view of no existing standard method in developing a middleware server, this paper outlines a methodology to design a 3-tier Client/Server database system. It identifies the role of middleware as temporary storage for better performance and as database gateway for Database Management Systems connectivity. Case studies are used to illustrate the steps.