Workflow Transaction Model

With increasingly the conflict between software's common use and individuation of software become sharp, as well as the improvement of Software Develop Thinking, it's pay more and more attentions to Workflow technology. Workflow is a basic business processes management platform that can be used to support the application systems such as BPR, BP automation and EAI. Form 2003, Workflow based enterprise application solutions have been emerged like bamboo shoots after a spring rain.WfMS (Workflow Management System) is mainly used in the two aspects: Business processes automation and business tier based enterprise application integration. Both aspects are attributed to large-scale application, so WfMS is often executed in heterogeneous, autonomous and distributed environments. Thus reliability is of critical importance to workflow system and becomes the key element of deciding the applicable scope of Workflow.In the paper the research of transaction in WfMS and transaction handle is established on practices. We analysis the difference between the transaction in WfMS and traditional transaction, Advanced Transaction. Based on the analysis we point out what's the most important and difficult in the transaction in WfMS. And TFlow that is a WfMS model with transactional feature was proposed. TFlow ueses Task element replaces with Activity element defined by WfMC, and classifies Task. To make WfMS support transaction process well, in TFlow, we give the conception of Transactional Task Group Restriction and Post-transaction. Combined use transactional Task, Transactional Task Group Restriction and Post-transaction can loosen the Atomicity and Isolation of traditional transaction, can also be as a practical method of dividing the long-running transaction. In addition, there is a multi-tires and extendable error model in TFlow. Finally, extended and modified the XPDL (XML Process Definition Language) to support TFlow model, called T-XPDL.