Object Constraint Language
The Unified Modeling Language (UML) includes a textual language called Object Constraint Language (OCL). OCL allows users to navigate class diagrams, to formulate queries, and to restrict class diagrams with integrity constraints. From a practical perspective, the OCL may be viewed as an object-oriented version of the Structured Query Language (SQL) originally developed for the relational data model. From a theoretical perspective, OCL may be viewed as a variant of first-order predicate logic with quantifiers on finite domains only. OCL has a well-defined syntax [1, 3] and semantics .
Navigation: The navigation features in OCL allow users to determine connected objects in the class diagram by using the dot operator “. ”. Starting with an expression expr of start class C, one can apply a property propC of class Creturning, for example,...