ADEPTevolution - Schema Evolution in Workflow Systems


The use of enterprise-wide standard software (e.g., ERP systems) often leads to a rigid implementation of the business processes. Respective software systems lack the necessary flexibility since process adaptations are expensive, time-consuming, and error-prone. However, the ability to quickly react to business process changes and to adapt process-oriented application systems accordingly is indispensable for any enterprise to stay competitive in its market.

Process changes range from ad-hoc modifications of single business cases to evolutionary changes of whole business process. The former are required, for instance, to deal with exceptional situations. The latter become necessary, for example, when new laws come into effect, optimized or restructured business processes shall be implemented, or rapid reactions to a changed market are required. Adaptive workflow technology offers a promising approach in this context.

Especially for long-running workflows  it is desirable to propagate workflow type changes (i.e., changes of the related WF schema) to running workflow instances (of this type) as well. Very challenging in this context is to correctly and efficiently adapt a (potentially) large collection of workflows which may be in different states and to which various ad-hoc changes may have been previously applied. In the latter case we do not only have to care about the current state of respective workflow instances, but must also cope with structural and semantical conflicts that may exist between workflow type and workflow instance changes.


Fig. 1: Schema Evolution and Related Instance Migrations

The overall project goal was to develop a comprehensive approach for workflow schema evolution and change propagation in (adaptive) workflow systems. In particular, we addressed fundamental issues related to the following fields: 

  • Comprehensive correctness criteria for dynamic workflow changes (e.g., compliance of workflow instances with a modified workflow schema)

  • Design and implementation principles for adaptive workflow models 

  • Efficient compliance checks as well as eficient and automatic migration of compliant workflow instances to a changed schema

  • Adequate treatment of non-compliant and semi-compliant workflow instances

  • Common support of changes at the workflow type and the workflow instance level 

  • Propagating workflow type changes to "unbiased" as well as "biased" workflow instances (i.e., instances without and instance with preceding ad-hoc modifications) 

  • Treatment of state related, structural and semantical conflicts that may exist between workflow type and workflow instance changes

  • Architecture and implementation of adaptive workflow technology 

Besides practical issues the very important aspect of our work was its formal style and rigour. We developed fundamental axioms and theorems for the correct treatment of dynamic and concurrent workflow changes. We consider this as indispensable in order to come to a comprehensive and implementable solution for adaptive workflow technology.

The developed concepts have been prototypically implemented in a powerful software demonstrator. The respective tool was presented at events like BPM'03, ICDE'05, CAiSE'06, and CeBit'06. An integrated implementation of the described features with other advanced process support functions is accomplished within the ADEPT2 project.


 Fig 2. Implemented Software Demonstrator


  • Institute of Databases and Information Systems


  • This research project was partially funded by the German Research Foundation (Deutsche Forschungsgemeinschaft; DFG)


  • 2001 - 2004


Prof. Dr. Peter Dadam

Dr. Stefanie Rinderle

Prof. Dr. Manfred Reichert

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