The Assignment relationship links active elements (e.g., Business Roles or Application Components) with units of behaviour that are performed by them, or Business Actors with Business Roles that are fulfilled by them.
The Assignment relationship represents the allocation of responsibility, performance of behavior, storage, or execution.
As with all structural relationships, an Assignment relationship can also be expressed by nesting the model elements. The direction of the relationship is also the direction of nesting.
Structural.
A Business Actor assigned to a Business Role. A Business Role assigned to a Business Process or Function. An Application Component assigned to an Application Function.