The object model for an application defines the relationships between the objects that comprise the application. These can be physical objects, like program source files or JCLs, or logical objects that identify abstract program elements: entry points, data stores, screens, jobs, and the like.
The relationships between objects describe the ways in which they interact. In the figure, the source file GSS.CBL defines the GSS program. The program, in turn, reads the data file GSS.FCSTSEC.