A data model is not only useful for specifying data structure, but it can also serve as a blueprint for computation. This chapter explores the use of model traversals as an aid towards preparing SQL queries.
16.1 The Object Constraint Language (OCL)
The Object Constraint Language (OCL) [OMG-2012] [Warmer-2003] is a textual language that is part of the UML, and is intended for specifying constraints. The class model, by itself, can express some constraints with its data structure. The purpose of the OCL is to express additional constraints that reach beyond the class model. For example, the online retail application might require that the shipping and billing addresses for an order be found in the list of addresses for that ...