Research on location-dependent queries in mobile databases

摘要

The radical evolution of stationary databases to wireless databases has created several novel properties, including mobility in particular. This property has created a new query operation namely location-dependent query. In location-dependent query, the location of the object becomes the parameter of the query, and since the object continuously moves from one place to another, it requires a complex mechanism to monitor the object location as well as ensure a valid query result. Location-dependent information services will soon become common, and providing efficient and effective mobile query services will be critical. However, due to inherent constraints, such as low bandwidth, short-life battery, limited storage space, and frequent disconnection, information services to mobile clients have been much restricted. In this paper, we present a state-of-the-art in data management for location-dependent query processing. We discuss location-dependent query processing techniques, which are focusing on server strategies, mobile client strategies, and on-air strategies. We further classify each strategy into dynamic and static location-dependent data.