Research And Application Of Multi-tier Distributed Database Structure

Along with the rapid development of database and network technology, distributed database system has been developed maturely not only on theory but also on extensive application. Distributed database system caters to the requirement of the current information management system application, adapts to the management methods and modes of the current enterprise organization. Therefore, distributed database has become an important part in information processing.Distributed database refers to a database with separated in different places physically but united logically, and it has characters such as using in common, independence, controllability redundancy and separated transaction of business. As distributed database system is not a simple combination of network technology and centralized database, it needs to achieve in a suitable system framework. At present, the system framework which achieves relatively easily such as multi-tier Client/Server (C/S) system framework and Browse/Server (B/S) system framework has been developed widely, and becomes the mainstream system framework in distributed database system.The paper researches the relevant theory of distributed database, compares the current mainstream system framework, analyses the architecture of distributed system, data fragmentation and data distribution which are the most important operation in distributed database system, and studies the main technology of distributed database.The paper emphasizes particularly on the practicability of distributed database, therefore, the paper studies and compares the distributed database model structures such as SQL Server and Oracle which have been most used currently, so that we can chose proper distributed database model to achieve distributed database system according to project's requirement which has been researched.Distributed object construction technique is the foundation to achieve distributed database system function, and the technique of accessing database is the key to achieve distributed database system. Therefore, through research and comparison, the paper chooses suitable distributed object construction technology and the technologyof accessing database. The paper chooses a reasonable database design technique which on this basis to achieve anticipative design objective and ensure usability and reliability of distributed database.At present, the large/extra bridge management in the direction of information management, according to the principle of one bridge one database, the paper presents to the distributed database system based on the mixture architecture of three-tier C/S and B/S and integration of geographic information system (GIS) ,achieves in the bridge integrate information management system. The study of this paper has important significance for the development of the bridge informative management.