Both of these source objects allow specification of relations that operate on them. Both also allow definitions of constraints that hold on each individual instance of the source object. It is not necessary to define a class or enumeration before its use. Enumerations Enumeration Enumerations describe attribute types. They specify the domain of the attribute.
Enumerations are finite and discrete.
Enumerations are atomic. They can not be constructed from composing other enumerations. Enumerations do not form an inheritance heirarchy. Attribute An attribute can be an instance of an enumeration, or an instance of another class. Each class can have at most one state vector.