A Research Of Data Access Middleware Of Enterprise Application

Based on data access middleware of enterprise application, this paper discusses the design and realization technology of MS COM based enterprise application.Firstly, the paper introduces the technology of distributed objects and middleware based multiple tiers architecture of software. Secondly, the function of data access middleware is defined and the technology of data access middleware is analyzed. Following that precondition, frame is given to build data access middleware. Thirdly, this paper introduces the design and realization of the data access middleware and gives an example of using this software. Finally, a summation is given.Main functions of data access middleware are location transparency, distributed data query, transaction process and heterogeneous data sources compatibility. Location transparency means that the locations of data sources' are transparent to the higher application. Distributed data query means that the middleware encapsulates data sources request in API and accesses data instead of applications that use it. Transaction process is a mechanism to insure the ACID properties of transactions between data sources. Heterogeneous data sources compatibility can connect the different data sources and accesses to them.The developing platform of data access middleware is Delphi 6+MS SQL Server 2000+MS Windows 2000 Server and the software's application platform is MS Windows 2000 Server. There are two modules in the software, one is application configuration module that provides interfaces for its user to customize data and the other is data server module that accesses data for its user.This paper centralizes on the realization of the data access middle software of enterprise application and studies the base services of distributed application of Microsoft corp. The infrastructure provided by operation system decreases the difficulty of the of the distributed software developing. At the same way, the data access middle software of enterprise data access service can decrease the difficulty and cost of the enterprise application developing.