OCLUNIV: Expressive UML/OCL Conceptual Schemas for Finite Reasoning.

Full UML/OCL is so expressive that most reasoning tasks are known to be undecidable in schemas defined with these languages. To tackle this situation, literature has proposed mainly three decidable fragments of UML/OCL: UML with no OCL, UML with limited OCL and no maximum cardinality constraints (OCL-Lite), and UML with limited OCL with no minimum cardinality constraints (OCLUNIV). Since most conceptual schemas make use of OCL together with min and max cardinalities, this poses a strong limitation to current proposals. In this paper, we go beyond these limits by showing that OCLUNIV with acyclic min cardinality constraints and path acyclicity constraints also preserves decidability. In this way, we establish a language that can deal with most of UML/OCL identified constraint patterns. We also empirically test the expressiveness of this language through different UML/OCL case studies.