Research On Transactions Processing In Embedded Mobile Database

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 like supporting mobility and disconnection on mobile transactions processing. Therefore it's very important to deploy research on mobile transaction model. So this dissertation proposes a new mobile transaction model called AOP-MT: Adaptive and Optimistic Policies for Mobile Transactions and takes some deep research. AOP-MT model can support operation in disconnection and allow mobile clients random move. It also supports interactive transactions and eliminates the unfavorable impact on database applications and transactions processing posed by mobile computing environment. Accordingly, the main contents of research on mobile transactions are as follow: 1) Analyze the impact on embedded mobile database and mobile transaction posed by mobile computing environment, which draws the demarcation of concerned issues in research. 2) Analyze the requirement of strict data consistency and weak data consistency in mobile computing environment, propose a new mobile transaction model called AOP-MT that can flexibly fits the different requirements. By analyzing the data information types in mobile computing environment, we select optimistic method for transactions processing. 3) Introduce mobile transactions processing in On-line mode and Off-line mode of AOP-MT detailedly. By importing MTC (mobile transaction coordinator), MTP(mobile transaction participator) and OPS(operation segment), it supports interactive transaction, allows mobile clients move randomly and supports operation in disconnection. It can ensure serializable transaction schedule and data consistency. 4) Analyze conflicts that perhaps appeared in AOP-MT, such as read-write conflict and write-write conflict. Propose methods to detect conflicts and ensure data consistency in On-line mode and Off-line mode. 5) Discuss recovery mechanism of AOP-MT model and provide a fundamental way to mobile transaction recovery. 6) Design a mobile transaction processing prototype based on AOP-MT. It explains the application of AOP-MT in prototype by giving an example. It can illuminate the feasibility of AOP-MT model.