Interval Constraints

An interval constraint requires that an attribute’s value must be in a specific interval, which is specified by a minimum value, a maximum value, or both. Such a constraint can be defined for any attribute that has an ordered type, but normally we define them only for numeric datatypes or calendar datatypes. For instance, we may want to define an interval constraint that requires the age attribute value must be in the interval [25,70].

Interval constraints in UML

In a class diagram, we can define such a constraint by using the property modifiers min and max, as shown for the age attribute of the Driver class in the following diagram.