Manet Mobile Database Systems, Transaction Management And Realization

Tremendous advances in computer hardware and communication have made mobile computing feasible. Mobile computing makes it possible that people can access information in mobile database anywhere at any time. The research on mobile database has become a new field on the database application and is very important to the development of the parallel and distributed technology. However, the properties of mobile computing environment, such as, mobile nodes, low power supply, low bandwidth and disconnection of wireless network makes it very difficult for the mobile database to be used for many applications.Most of the transaction management schemes for mobile databases are based on the wireless network with mobile support stations and are not suitable for MANET environment. In this paper, a new transaction management scheme based on MANET environment is presented. The scheme is based on 2PC using time stamp. An algorithm to accomplish serialization validation is provided so that the serialization of the transactions can be done. The proof of the algorithm is also provided. The experimental results to analysis the relationship between the fraction of abort and the number of the transactions is given. To decrease the number of the transaction abort due to the disconnections of the mobile nodes, this paper present a proxy based method to deal with this problem. Experimental results show that the method can greatly reduce number of the transaction abort due to the disconnections of the mobile nodes. This paper provides a group based multi-skip data replication method for MANET environment. By replicatingthe partial data of one mobile database on other nodes of the same group in a multi-skip way, the distances of the data transmissions for the queries of mobile nodes are reduced. As a result, the cost of the communication is lowered and the response time of the query is shortened.