You can specify relationships to identify the semantic ties that exist between the elements in a model.
Adding relationships to diagrams
In UML diagrams, you can add relationships to diagram elements to describe how they relate to each other.Extending the behavior of use cases
In UML modeling, when you draw use case diagrams, you communicate the essence of the system or application without exposing any unnecessary details. It’s generally good practice to hide the complexity of the system, but there are times when you might need to expose details. You can depict these details in their own use cases and connect them to the base use cases, which enables you to reveal information that would otherwise be hidden.Specifying association relationship types
When you add associations between the classifiers in your model, you can specify a particular type of association relationship.
Parent topic: Modeling the behavior of a system by using use case diagrams
Related concepts
Use case diagrams
Relationships between model elements