Research Of Multi-Agent Based Cooperative Database Environment In CSCW

CSCW (Computer supported cooperative work) researches on how a group of people to complete a job together drawing support from computer network environment. It is an inter-discipline that needs Computer network, Communication technology, Multimedia technology supporting it and also some Society disciplines such as Sociology, Psychology and Management science et.CSCW system supports customers that distributed in locations to work cooperatively. Essentially it is a distributed system and it supplies various communicating styles and supports multimedia data transference. It supplies the customers many functions to share their data. At the same time, CSCW system allows customers to operate simultaneously and keep the shared data consistent."What you see is what I see" is the result that people want to get while doing cooperative work. So the participators need to describe their states and the data communicating with, and get them to be known by other participators. Other participators get the information and reappear them, then, people could know the others exactly. Data sharing is the basis of cooperative, so we can say that the database determines the level of cooperation.But now in a cooperative group, different participants may use different way to store data, or it may be described differently, or customers may use different database system, such as Oracle, MS SQL Server, Sybase SQL Server and so on.So how to make the different database systems to work cooperative is a new problem.As the cooperative work is being used more and more popular, the scale of the participators, the data and the loads of communication become larger and larger, more and more distributed systems join in a CSCW system, coming with their different database systems or data logic structure. Then in the CSCW environment come out a group of database systems that may be different in logic structure, data management style or the hardware and software they working in.So the Database Cooperative Management System (DCMS) is built to solve these questions. The DCMS is composed of some existing, distributed and autonomous database systems that may be different in structure. The DCMS is a "system of system". It is built to cooperate these databases or data source and keep them independent relatively when working alone. With DCMS every participator in CSCW could use the same interface and needn't to care the concrete translation of data structure.In this paper we will synthesize the characteristics of Distributed Database System and Multi-Database System to build a cooperative database system model. This system will be based on the common database systems such as SQL Server and Microsoft Access. And more important, in our system model we use the "Agent" to solve the key point problems, such as the transform of data difference and the concurrency control of cooperation transactions. The main work we have done in this paper include the followings:(1) We have done some research on the background and current situation of CSCW and database cooperative supporting in CSCW. For the issues exits in CSCW system and the needs in the reality, we put out the problems need solving and improving in database cooperative work;(2) Because of the difference and distribution of the database systems in CSCW, we draw the "Agent" into our system model We have built an environment model based on MAS, and in this model the problem of data difference and concurrency control will be well improved;(3) And also we need the technology of XML. We introduced a XML based model. With this model the problem of schema mapping of different systems will be solved. Then in the CSCW system we could make the cooperative environment consistent and also every local system could be kept independent;(4) After doing some research on the transaction management and concurrency control, we also give some train of thought about them;(5) Using XML document we set up a resource table in DCMS. And we use XML document as the media of data transmission and standardize it by DTD. Though this people in CSCW could share the different data in a common way.In this paper we didn't realize the whole system completely. We just do some practice on some key functions, and give some suggestions on the relative issues. There is still much work needs us to do. But I hope this paper could bring us some enlightenment in this field.