A type of collection in which the values are unordered and unique. A type of Set in which the values are all direct instances of the same type of abstract object, and in which the abstract object attributes all have primitive domains. An enumeration describes all possible values which may be assigned to the attribute in question. PrimaryColor may be defined as an enumeration consisting of the values red, green, and blue. The named values of an enumeration are sometimes referred to as enumerates.
Primitives are the basic building blocks of data values.
Integers and reals are both considered as types of numeric data. Integer16Unsigned , Integer32, Integer32Unsigned , Integer64, or Integer64Unsigned. Instances of reals may be categorized as Real32, Real 64, or Real80. Similarly, in the definition of a subclass, an attribute defined as optional in the superclass may be restricted in the subclass to be nil, i.e., as not to be used. Attributes and their associated domains are designated in the definition of a class.