Displaying an N-ary Association
Certain associations associate more than two classes. These associations are generally rare.
Example: When taking inventory, a certain quantity of product was counted in each warehouse.
To create a ternary association:
1. First create the association between the two classes.
2. Click the
Association Role button

3. Draw a link between the association and the third class.
You can then proceed as described above to create an association class if needed.