Establishing Service System Of Chemical Resource--The Implement Of Chemical Data Querying And Estimating System

Since 1990 s, old theories on database system and technology no longer fit the information times. So, advanced theories and technology must be adopted to improve chemical and technological database system.The two-tier model was innovative in its times because it off-loaded computational tasks from the main processor onto a smart client machine. As the client-server model has grown in use, concerns have been raised about scalability on the server, as well as code size and complexity on the client. A three-tier architecture has been proposed to alleviate perceived weaknesses in the two-tier model and to put business logic in the middle-tier. With the increase of requests from the Internet, at the same time, we need only to do is to increase the number of application servers. Now, there are three kinds three-tier models: there are MTS/COM+, CORBA and EJB. Every of them has advantage and disadvantage themselves. Because the developing platform of my project is the Solaris of Sun and because of the efficiency of develop and the servers that can afford, EJB is chosen.The framework of search and estimate about chemical and technological has been constructed, search and estimate about chemical and technological has been implemented in the system. Many advanced technology in computer field, just like EJB, JavaBean, Servlet, JSP, xml, and UML, have bean applied in our system. Moreover, the tool of "struts web tools" has been developed to accelerate the development of the system; A class of database connection-pool has been implemented to improve the utility of database connection; XML has been adopted in our system to enhance the flexibility. And the special group of "211 Project" in Beijing University checked and accepted the system on June 23 in 2001.