4. Structural Aspects

This chapter covers structural aspects of models, namely inconsistency and (in)dependencies. In the first part of this chapter, contradictory UML/OCL models are analyzed in order to aid the designer in determining the reason for an inconsistency. More precisely, a method is introduced step by step how to detect the different types of issues which can make a model inconsistent. Afterwards, the second part of the chapter analyzes (in)dependencies between the constraints added to a model and determines reasons for dependent constraints. This gives the designer the possibility to keep the model as small as possible and, thus, not over-crowded with redundant information. Finally, the ideas of the first two parts are compared with a similar problem from the SAT/SMT domain: how to determine all minimal unsatisfiability cores.