Research On Synchronization Of Mobile Database Base On Transaction

The development and the combination of the computation technology and the wireless communications comes out a new computation pattern, making the mobile computing into the reality. Driven by the application requirements, and with the development of telecommunications, hardware technologies and corresponding software technologies, the mobile computing pattern is developing at a high speed and plays an important role in more and more areas. The mobile database comes to existence and is being further developed just to meet the data storage requirements in the mobile computing environment. In the mobile computing environment, the maintenance of data consistency is the main issues that need to be resolved in mobile database applications. However, there is a huge difference between mobile computing environment and the traditional fixed distributed computing environment, making the data synchronization work of maintaining data consistency face great difficulties. The traditional data-processing pattern can hardly meet the needs of mobile computing environment. Therefore, there is a need to further research on the data synchronization technology which is based on the mobile environment characteristic. This thesis focus on the transaction-based data synchronization in the mobile database, the main work and innovation includes:Firstly, comparative analyses to characteristics of the existing typical mobile database transaction processing models. Based on this, an extended optimistic two-phase commit transaction model is proposed. The model incorporates the design idea of the 02PC-MT model, uses the transaction queuing mechanism to support the mobility of transactions and adopts the strategy of optimistic concurrency control and the two-stage committing to achieve the consistency of data, mobile transaction processor is introduced and JavaCC is used to realize a transaction processing parser.Secondly, an in-depth study on the process for the mobile database transaction consistency is performed, the main synchronization strategy for heterogynous data sources from SyncML-based mobile database and its drawbacks are analyzed. Aiming at the problem of lacking flexibility, a new synchronization strategy is proposed and its key technologies are also developed and realized. Through comparative analyses, the synchronization strategy can improve the degree of flexibility, making it suitable for the use in the mobile computing environment when a large amount of data need to be synchronized.Finally, due to the limit to the resource in the mobile devices and the uniqueness of mobile network bandwidth, the synchronized optimization problem should have been the key research topic in the mobile database area. However, the research on this field is rare. In the transaction combination based synchronization optimization method proposed in this thesis, through two examples, introduces a method based on associative transaction and semantic transaction combination. The combination of transactions can effectively defuse synchronization conflict and reduce the synchronization numbers.