Representing Model Differences by Delta Operations

Software models are subject to subsequent changes. Models evolve over time to meet changes resulting in several versions. The differences between subsequent model versions are represented in differences documents usually referred to as Modeling Deltas. The model differences are used in establishing several further services and operations of version control, collaborative modeling and history analysis tools for software models. Therefore, finding an adequate difference representation approach is essential for applicability, re-usability and analysis of the model differences. This paper introduces the Delta Operation Language (DOL), a meta-model independent and operation-based concept to model difference representations. The proposed approach provides several operative DOL-services for utilising the DOL-based differences. The application areas of DOL include Model Versioning, Model History Analysis and Collaborative Modeling. The approach is applied to UML activity diagrams as a running example.