Component-based "Digital Products Sale Information System" Design And Implementation

With the continual development of software science,especially Internet and Intranet,software application has been used in a wider and wider environment. This puts forward a much higher request that the software should be cross-language,cross-platform and inter-operation. Under this condition,the traditional object-oriented methods have been difficult to adapting to currently distributed software application, now the methods of component-based software development develop rapidly.The methods of component-based software development make it possible that software products can be constructed quickly like putting up bricks. Within this procedure we not only shorten the period of development, but also improve stability and reliability of application system. Now there are three kinds of component model supporting the methods of component-based software development, they are COM/DCOM/COM+,CORBA,EJB. COM is mainly used on the platform of Microsoft Windows OS.Component Object Model is a software criterion based of binary system standard and be independent of the program language. It defines how to load object and define component and create component. It also provides realization portion-com library which provides the system services .What those system services do includes the components orientation,inserting the components into the memory,and also includes some other operation such as the execution of the communication in and out of process. Fundamental characteristics of COM are language independent, process transparent and software reusable. These characteristics make component-based software development possible. By using MTS and DCOM,we can create a multi-tier distributed application system,and by the aid of new functions of COM+(QC,CLB etc) ,the application system will work better.On the basis of doing further researches into the main framework of the COM Technology and describing the technology concisely , we applied COM in the design and implementation of "Digital Products Sale Information System". Thus, we brought the COM theory into the practice of developing Large-scale Distributed Information Management Systems. We also brought the excellent characters of XML into the design of the Information System in practice,also we put forward our own viewpoint of abstraction for enterprise business logic and the acquaintance on the component granularity. This system has been working in a digital products sale company for more than half a year,the working results shows:(1)It works very well,sufficiently reveals the advantages of COM (such as reusable,stable and extensible). (2) The using of this system brings social benefits in a degree. It provides a successful example and is worth studying by. (3) This system also brings big economic benefit for the company, it improves the company's management efficiency and contest ability, contributes to earning more profit for the company.