The concepts of superclass, subclass, and inheritance are similar to those discussed for
the Enhanced Entity–Relationship (EER) model in Chapter 12, except that in the objectoriented
paradigm inheritance covers both state and behavior. The relationship between
the subclass and superclass is sometimes referred to as A KIND OF (AKO) relationship,
for example a Manager is AKO Staff. The relationship between an instance and its class is
sometimes referred to as IS-A; for example, Susan Brand IS-A Manager.