What are classes?

A class is a logical grouping of objects within a universe. In general, the name of a class reflects a business concept that conveys the category or type of objects.

For example, in a universe pertaining to human resources, one class might be Employees. A class can be further divided into subclasses. In the human resources universe, a subclass of the Employees class could be Personal Information.

As designer, you are free to define hierarchies of classes and subclasses in a model that best reflects the business concepts of your organization.