Data Types

The heading 'data types' groups all the abstractions underlying UML. They are not model elements, and therefore they do not have stereotypes, tagged values, or constraints. A primitive type is a data type that has no substructure.

Simplified metamodel representation of some UML data types.

The following is a list of UML data types:

• Boolean. A Boolean is an enumerated type with the two values

  True

  and

  False

  .
  
  
• Expression. An expression is a character string whose syntax goes beyond the scope of UML.
  
  
• Multiplicity. A multiplicity is a non-null set of positive integers extended by the character

  *

  to indicate an unlimited multiplicity. The multiplicity is specified by a comma-separated sequence of integer intervals. For example, intervals of the form

  0..1

  and

  1..10

  indicate multiplicities of 0 to 1 and 1 to 10 respectively.
  
  
• Name. A name is character string that enables the specification of an element. Composite names take the form,
  
  

• simple_name{'.'composite_name}

  
  
  
• and may be qualified by the name of its containing or referencing package:
  
  

• package_name{'::'simple_name}

  
  
  
• Integer An integer is a primitive type, which is an element of the infinite set of positive and negative whole numbers.
  
  
• String. A string is a primitive type. It is a sequence of characters referred to by a name.
  
  
• Time. A time is a character string that represents an absolute or a relative duration, whose syntax goes beyond the scope of UML.
  
  
• Uninterpreted. An uninterpreted type is a 'thing' whose meaning depends on the domain, and which is undefined in UML.