This would actually help solve some of the same issues that relationship properties would solve. Relationship properties - #28 by karthikk_vijay
One of the issue for related 3 databases in Many to Many type relationships is that fields on the relationships cannot be displayed on tables of parent entity. Or if they are then only counts are displayed not the piece of data we need. As such, being able to have data in fields that is dynamic to context would allow us to see this data on a table.
This is a bad example, and there are bigger applications to this idea. But this helps visualize the need:
In my Contacts database I have a relation to the Email database called “Email Addresses”. This way a contact can have unlimited email addresses. However, when I am on a table view of contacts, I want to be able to see an email for that contact. To do this I created a new field on Contacts called “Email” in order to have an email display on the Contacts table. However, let’s also say that email was associated with an Account. Now when I am on an account and I want to see the contacts associated with that account, I may also want to see only the email address on that contact that is associated with that account. Right now there is no way to do this because the email field would need to be a different value depending on the Account that I was on.