This section describes how you can change the properties of an association to make both entities its owner.
Create the association if it does not exist yet. If you do not know how to do this, refer to this article.
Select the association.
In the Properties window, use the drop down menu next to ‘Owner’ to set it to ‘Both’.
Both entities are now owner of the association; this is indicated in the domain model.
The above screenshots show the same association; the first shows it using hierarchical notation, whereas the second shows it using UML notation, which was added in version 2.5.1. You can switch between these modes using the Edit > Preferences menu.