Managing business workflows using a database approach: A formal model, a case study and a prototype

摘要

Workflows are an integral part of an organization, and managing them has long been recognized as important. With recent advances in information systems, there has been a great deal of commercial and research interest in developing workflow management systems (WFMS) to help businesses manage their workflows. In the database literature, much of this work has concentrated on developing advanced transaction models that can essentially handle long-lived transactions. Many WFMS tools have been developed in industry, each usually supporting different abstractions. The current process of constructing a WFMS application consists of obtaining user requirements informally, and writing the WFMS code using a WFMS tool. Since WFMS tools are evolving, and an accepted set of abstractions that should be supported by a WFMS tool does not exist, this process is unstructured and sensitive to the WFMS tool used. This dissertation aims at providing structure to the process of developing a workflow application. Borrowing from the established process of developing a database application, we follow a "top-down" approach: use a formally defined conceptual model to capture user requirements, and then map the conceptual model to the implementation model. We first developed and formally defined a conceptual workflow model (SEAM). Since the completeness of a conceptual model in a new domain (such as workflow requirements) is important, we have also developed and tested a methodology to test the completeness of conceptual workflow models. The next step is to show how SEAM can be mapped to an implementation model. We have selected the current abstractions of computationally complete data manipulation languages, triggers, stored procedures and support for embedded data manipulation languages as the target implementation model. SEAM is mapped to this model, and a prototype is implemented as an example. Thus, this dissertation provides sufficient information to construct an automated WFMS, built on currently available abstractions. In addition, the dissertation also provides a methodology that can be used to empirically measure the completeness of conceptual workflow models.