Incremental view update for a mobile data warehouse

In a mobile environment, querying the database at a stationary server by a mobile client is expensive due to the limited bandwidth of a wireless channel and the instability of the wireless network. We address this problem by maintaining a materialized view in a mobile client's local storage. The materialized view contains results of common queries in which the mobile client is interested. We term such a materialized view, a mobile data warehouse. In this paper, we address the view update problem for maintaining a mobile data warehouse, viz., changes to the database should be reflected to the derived materialized view in a consistent manner. Existing view update mechanisms are "push-based". The server is responsible for notifying adi clients whose views might be affected by the database changes. This is not appropriate in a mobile environment due to the frequent disconnection of a wireless channel. We propose a "pull-based" approach that allows a materialized view to be updated at clients incrementally. Our approach requires a client to request changes to its view from the server when the client needs it. We will demonstrate the feasibility of our approach with preliminary experiments via simulation.