Editing Several Entity Properties at the Same Time
Save time by editing several entity properties at once. You can select as many properties as you want to edit at the same time, even from different entities.
With the detail and utility areas open in table mode, select the entity or entities you want to edit.
In the detail area, select a property—an attribute or relationship.
Hold down the Command key, then select additional attributes or relationships as appropriate.
In the utility area, select the Core Data Model inspector and set the property attributes as you want.
The screenshot shows the two attributes selected in the Author entity and one in the Book entity.