Real-time Transaction Processing in a Mobile Environment

With the advances in mobile computing technology .there is an increasing demand for processing real-time transactions in a mobile environment. This paper proposes a multi-version data model. Based on this data model, we present a relative timing correctness criterion for real-time transactions in a mobile environment. As long as the data staleness is in a controlled extent, it is unnecessary for all the accessed data are valid when a real-time transaction commits. Also this paper gives a transaction execution model based on the image transaction concept. All these strategies not only decreas the cost for the transaction concurrency control,but also increase the possibility to meet mobile real-time transactions'deadlines by sacrificing the relatively transaction timing correctness. This is in accordance with the real-time transaction property that a relatively correct and in-time result is more preferable than an absolutely correct but obsolete result.