Rule-based (re)active systems are a commonly accepted solution in the area of nonstandard applications in order to express an event-driven and constraint-driven system environment. Several attempts have been made to integrate active concepts into object-oriented databases and to extend active knowledgemodels to gain more and more expressive power and flexibility. Unfortunately, execution models of active systems do not fully exploit all the advantages of the provided knowledgemodels. Among the most challenging research problems is the development of a transaction model in the presence of so called composite events. Our approach of multi-parent subtransactions tries to fill this gap. Multi-parent subtransactions extend the well-known nested transaction model by allowing multiple transactions to start a subtransaction in cooperation. In particular, this paper discusses the impacts of our extensions on the locking protocol of the original nested transaction model.
Author and article information
Department of Computer Science
University of Linz, A-4040 Linz, Austria