Design And Implementation Of Transaction Model On A Embedded Mobile Database System

Transaction processing is a basic function of the database management system, it is used for maintaining the consistency of the data mainly, support the multi-user's concurrency visit, make user can query and update the database reliably. It is demand that mobile database system offer transaction processing ability too, in order to meet the mobile applied requirement. On Account of the paritcularity of mobile computing environment, it is necessary to consider the question which needn't consider in traditional computing environment in designing mobile database system, such as mobility of the client, frequent disconnecting, weak connection, switching in different areas and so on. So how to make server dispose mobile transaction perfectly become a very important subject.In this paper, firstly the basic of mobile database system has been discussed, including conception, characteristic and actualities. Then the classes, the architecture and the key technology of mobile database are discussed. proposed HS-MT mobile transaction model that supports transaction mobility, frequent disconnect and data consistency effectively base on it. HS-MT attract the design thought of 02PC-MT model, use queue supports the transaction mobility, adopt optimism simultaneously control and two stage submit supports the transaction mobility, aim at fact demand transaction processing would disport strict consistency mode and weak consistency mode. Strict consistency mode base on whole mobile database system keep connection, mobile client don't save data duplicate, immediacy access fix databse server, support mutual transaction, permit stride section move, support disconnection and weak connection, use queue supports the transaction mobility, adopt optimism simultaneously control and two stage submit supports the transaction mobility. Weak consistency mode in order to provide mobile host'autonomy disposal, mobile client save data duplicate, tansaction compute and process completed at home, make the best of the mobile host'resource and processing capability, support disconnection and autonomy, two stage submit guarantee data consistency, improve system capability.