The Information Integration Based On Distributed Database

With the development of the society, the drastic competition requires the enterprises make quick responses according to the changes of the market. In order to improve the ability of comprehensive competition, and deal with the variety of market information, every enterprise is speeding up the construction of information. One of the key work is to integrate all kinds of management information systems and data effectively. Nowadays, more and more enterprises have set up to change their focus to the structure of system integration. All enterprises are solving business integration and defining the integration system and basic framework for the future development of themselves. So, the needs for the integration of heterogeneous data sources will be urgent and last long.Data interoperability is one of the main problems in information integration. There are two approaches to solve the problem of integrating heterogeneous data sources. one is the solution of information integration based on Mediator, and the other is the system of distributed database. After analyzing these two approaches detailedly, this dissertation presents a new solution of the integration of heterogeneous data sources. The solution not only fulfills the independence of dealing with data, but also provides an approach to integrate various heterogeneous data sources, which meets the real world application.Based on the schema of the system of information integration, the dissertation presents a common data model (JIDM) which is a relational data model based on java. The model provides the ability to operate and save the relational data, and uses a serious of methods to descript the meaning of relational data. The mapping between global schema, export schema and local schema is presented based on the model, which solves the problem of mapping between JIDM and relational data, XML files, object-oriented data model.Query processing is one of the key techniques in information integration. The dissertation introduces query decomposing, query optimization, query scheduler, sub-query combination. A query tree can be got from the query decomposing rules, and a query graph can be generated by optimizing the query tree and applying the arithmetic of generating a query graph. At last, a query plan will be generated by using Kruskal heuristic arithmetic two times on query scheduler and sub-query combination.Based on the above theories and the framework of the information integration, a...