Association

An Association is a modeling Relationship that classifies a set of possible Links among typed Instances and expresses participating Types, Association Ends, roles, Multiplicity, navigation, and related semantics. SimpleModeling uses it to describe domain or structural meaning among Objects separately from implementation references.

In UML 2.5.1, an Association is a Relationship that classifies a set of Links, where each Link is a tuple of values referring to typed Objects. An Association End expresses a participating Type, role, Multiplicity, and related properties. Aggregation and Composition are whole-part Relationships represented by the Aggregation Kind of an Association End.

The ordinary word association or relation may describe a loose connection among topics, documents, or events. The Association defined here is a Model Element with participating Ends and constraints. Ordinary prose such as related documents or related processing is not a reference to this term.

SimpleModeling uses Association as the basic Relationship for expressing domain or structural meaning among Objects. It is not identified with a reference implementation or database foreign key.

Association expresses structure on the Object side. It is distinct from functional dependency or function composition; using functions to operate on an Association does not identify those concepts.

CML (Cozy Modeling Language) makes Association Ends, roles, Multiplicity, navigation, and required constraints explicit. When whole-part semantics apply, the model uses Aggregation or Composition rather than leaving the meaning as an undifferentiated Association.

Scala fields, references, and collections may realize an Association, but do not by themselves fully express its domain meaning, roles, Multiplicity, ownership, or Lifecycle.

simplemodeling-lib attributes, collections, schemas, and related structures may realize Associations. The Relationship kind is preserved from the canonical model rather than inferring Association, Aggregation, or Composition from implementation Types alone.

Japanese articles and videos introduce the term as 関連（Association）. Because the ordinary word 関連 is not registered as a bare SmartDox auto-link candidate, the glossary uses the qualified canonical label モデル上の関連. The short form is used only after the modeling concept is established.