Semantic cache schema for query processing in mobile databases

Wireless technology and its beneficial applications encourage users to use PDA, laptop, cell phone, etc to access data anytime and anywhere. In mobile database systems as a distributed system extra problems such as location dependent queries, validity of results are mooted. Semantic cache is of the best solutions proposed for query processing in which data and its semantic description are cached in the client system. Existing semantic cache schemas are not capable to answer all type of queries and there is a need for such a solution. In this paper, an exhaustive semantic cache schema is presented that is able to answer all type of queries such as join and group by. It uses query graph model to achieve this goal. In this schema, as a semantic cache schema, structure of cache items based on query graph model, cache management algorithm and also cache items replacement algorithm are proposed. Simulation results show that using this schema improves performance of query processing in mobile database systems in term of response time, required bandwidth and also number of connections to the server.