association class [English]

Syndetic Relationships

InterPARES Definition

n. ~ PaaST · A Unified Markup Language (UML) element that is simultaneously an association and a class.

General Notes

As an association, it links instances of two other classes. As a class, it may have features of its own. Each instance of an association class links one instance of each of the two classes that it associates.


  • OMG UML 2.5 (†861 p. 197): An Association classifies a set of tuples representing links between typed instances. An AssociationClass is both an Association and a Class. . . . ¶ An Association specifies a semantic relationship that can occur between typed instances. It has at least two memberEnds represented by Properties, each of which has the type of the end. More than one end of the Association may have the same type. An Association declares that there can be links between instances whose types conform to or implement the associated types. A link is a tuple with one value for each memberEnd of the Association, where each value is an instance whose type conforms to or implements the type at the end. (†2485)
  • OMG UML 2.5 (†861 p. 198): An AssociationClass is a declaration of an Association that has a set of Features of its own. An AssociationClass is both an Association and a Class, and preserves the static and dynamic semantics of both. An AssociationClass describes a set of objects that each share the same specifications of Features, Constraints, and semantics entailed by the AssociationClass as a kind of Class, and correspond to a unique link instantiating the AssociationClass as a kind of Association. ¶ Both Association and Class are Classifiers and hence have a set of common properties, like being able to have Features, having a name, etc. These properties are multiply inherited from the same construct (Classifier), and are not duplicated. Therefore, an AssociationClass has only one name, and has the set of Features that are defined for Classes and Associations. (†2486)
  • PaaST (1.0) 2017 (†860 p. 15): An association class is a model element that has characteristics of both an association and a class. It simultaneously associates two other classes and has attributes and possibly behaviors that are characteristics of the association. Each instance of an association class links one instance of one of the associated classes to one instance of the other associated class. (†2496)