Cardinality Constraints

Let’s learn about cardinality constraints.

A cardinality constraint requires that the cardinality of a multi-valued property’s value set is not less than a given minimum cardinality or not greater than a given maximum cardinality.

Cardinality constraints in UML

In UML, cardinality constraints are called multiplicity constraints, and minimum and maximum cardinalities are expressed with the lower bound and upper bound of the multiplicity expression. This is shown in the following diagram, which contains two examples of properties with cardinality constraints.

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