Unsatisfiability Reasoning in ORM Conceptual Schemes

ORM (Object-Role Modeling) is a rich and well-known conceptual modeling method. As ORM has a formal semantics, reasoning tasks such as satisfiability checking of an ORM schema naturally arise. Satisfiability checking allows a developer to automatically detect contradicting constraints. However, no complete satisfiability checker is known for ORM. In this paper, we revisit existing patterns from literature that indicate unsatisfiability of ORM schemes i.e., schemes that cannot be populated, and we propose refinements as well as additions for them. Although this does not yield a complete procedure – there may be ORM schemes passing the pattern checks while containing unsatisfiable roles – it yields an efficient and easy to implement detection mechanism (specially in interactive modeling tools) for the most common conceptual modeling mistakes.