Researchon And Application Of Synchronization Update Of Distributed Heterogeneous Database

With the rapid development of the information age,Database technology is used more and more widely accompany. Due to the difference of system development environment and database type which caused by many factors such as individual environment, there are many independent information management systems, information service systems, and different database systems, while many data in those systems are interconnected. For the sake of maintaining the date consistency of local databases in distributed environments, a common and secure platform should be built to synchronize the data among distributed databases, so it can be used for the unified management of information and the rapid development of enterprises.This project is based on the requirement of digital simulation platform of high speed train collaborative simulations in Modern rail transportation National Laboratory (chips), aims to maintain the data consistency in real time which shared among professional database, shared database, foundation database and spatial database. According to this requirement, a synchronization method based on the" mapping file" has been proposed.The method captures the synchronous data in way of trigger and changed trace table, and uses XML as the representation about intermediate data which can improve expansibility and be exchanged among different databases easily. This method avoids the unified standard problem among heterogeneous databases, and solve the problem cause by these cross-platform systems. The mapping file is the bridge of the whole system, it not only build up a mapping relationship between the source table and the destination table in synchronous system.but also solve a lot of conflict problems among heterogeneous databases,improve the universality of the system, expansibility and the application ability in varieties of complex environments at the same time.The system frame of achieving this synchronization method is proposed. The frame consists of data source registration, the mapping from table structure to XML, capturing changed data, extracting synchronous data to XML Mapping File, it emphasize the analysis of the main technology in this system. Finally, this paper optimize properties of this scheme and find that optimized project shorten synchronization time ten times the previous one.Finally, an overall test has been made for this system in two parts to verify the feasibility of the scheme, then the feasibility and rationality of this scheme will be proved by an example, in the meantime the numbers of synchronous records and the simulation diagrams will be provided.