Transaction Technology for Process Modelling

Process Modelling (PM) is a software engineering discipline that aims at supporting the development of large and complex software systems. Therefore, PM focusses on study, de nition, enaction, and possibly improvement of software process models. Traditional transaction management (TM) protects data against unexpected system failures, con icts or inconsistencies. TM is also used in other areas, such as software engineering, to provide concurrency control and failure recovery for both automatic and manual activities. Transactions are typically used to provide reliable working contexts for software developers and for PM systems that enact process models. Software engineering TM adds requirements, such as support to user interaction, long lasting activities, non-programmed operations in the context of one transaction, and activity coordination. In this paper we will look at some aspects of using transaction technology to support enaction of software process models. We de ne a simple transaction model and then discuss various ways transactions can be used in enacting the ISPW '6 PM example problem [KFF90]. The focus of the discussion will be on structural aspects of both process models and transaction models. We identify problem areas, requirements to transaction models and choice-points in enacting a process model. By looking at process models, we nd that more information about the enaction must be speci ed to be able to map it to a single execution of a set of transactions. The structure of the paper is as follows: We rst present some PM terminology and the ISPW '6 PM example problem. We then turn to transaction models and introduce a simple model typical for the class of transaction models used in PM systems. The next section discusses how parts of the example problem can be enacted in terms of issuing transactions against a database containing the software objects used in the example.