Research On Transaction Processing Over Mobile Database Based On Agent

Rapidly advancing in mobile computing makes it possible that people can access information in distributed database by mobile client anywhere at any time. However the limitation caused by mobile computing environment, such as unreliable communication, frequent mobility, imposes many restrictions. Mobile computing and unique characteristic make existing DBMS unable: to support the mobile computing environment effectively, so must to mend or redesign traditional database, form a kind of database technology that can support the mobile computing environment in an all round way, that is Embedded Mobile Database.Transaction processing is a basic function of the database management system, it is mainly used for keeping the consistency of the data mainly, supporting the mufti-user's concurrency visit, making 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 particularity 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 make server process mobile transaction perfectly, namely solve the above-mentioned key technology problem of mobile transaction and become a very important research subject.This article introduces the technology of Intelligent Agent into the field of mobile database, through analyzing the characteristic and the goal of the mobile database.After analyzing the characteristic of the subsequent control of mobil transaction, this article proposes a Mixed Optimism-Pessimism Transaction Processing strategy which is based on Inteligent Agent technology and depicts it in detail. Then a conflict detecting method of optimism executing phase in MOP-TP strategy is proposed. After that, we study on the subsequent control of nested sub-transaction and work out a Dynamic Assigned Priority Two-Phase Locking(DAP-2PL) protocol based on lock.At last this paper proposes a mobile transaction processing model called Dynamically Configurable Mobile Database(DCMDB) which is based on agent technology and explains the architecture and the working flow of the model. Then we design a query engine of the DCMDB model.