The Object Constraint Language (OCL) is a declarative language for describing rules that apply to Unified Modeling Language (UML) models developed at IBM and now part of the UML standard. Initially, OCL was only a formal specification language extension to UML.^[1] OCL may now be used with any Meta-Object Facility(MOF), Object Management Groupm(OMG),eta-model, including UML.^[2] The Object Constraint Language is a precise text language that provides constraint and object query expressions on any MOF model or meta-model that cannot otherwise be expressed by diagrammatic notation. OCL is a key component of the new OMG standard recommendation for transforming models, the Queries/Views/Transformations (QVT) specification.

Part 3 OCL: Derivation Properties

The MDriven Book - See also: Certain important constructs