A locking model for mobile databases in mobile environments

Frequent and unpredictable disconnection of communication may cause database operations that are executed in mobile environments to be delayed. A shared data object that is locked at a disconnected mobile host could obstruct operations of other connected hosts. In this paper, we discuss a locking model for mobile databases to deal with this challenge. The objective of the locking model is higher throughput of mobility supporting systems. As explained in this paper, this is achieved as follows. First, a requested lock from a mobile host can compete with existing locks on a specific data item. Second, a write lock request can gain control over read locks and an online lock request can take over offline locks. The approach of the lock model is that data downloaded into the mobile devices with intended modification. It is only write-locked when the actual operations on it are being executed. The locking model, in addition. supports cooperative operations and increases awareness in mobile working environments.