You also get the benefit of working with a 4GL rather than with a 3GL like Java. DAMs are provided for all the leading database vendors including Oracle, Sybase, and Informix. A library could be viewed as a project or, more appropriately, like a package. A library contains the classes, tables, and tasks associated with a single element of an application. Just as with any object-oriented environment, a developer uses classes to create instances.
Instances communicate via message passing or by events.
The final element in the jigsaw is a task that executes the application, holding the instances and running the methods. This is a library browser for a simple Music application. This application holds information on a CD collection. A session wizard object that was used to create the music window and log-on screen is also included. It includes classes for windows, menus, toolbars, and report generation, lists and grids, as well as a set of Internet classes.