Allow shared object (no Foreign Key) relationships

[jhandel]

I run in to a number of situations where I want to share an object type across multiple parents.. Could be a Contact, Address, Image&MetaData. I would like support for a "shared" entity.. one that is based on a parent ID and discriminator.. While navigating from the child (Contact, address, image, etc) to the parent would be non-trivial, the vast majority of the time this use case is from the parent to a collection of children. Currently without adding a bunch of one off inherited objects and a nullable FK for each parent type this is not doable, and that approach is disliked by many a DBA..

Ideal use case:
Contact:

• Id
• ParentId
• ParentDiscriminator
• [the rest of the fields that make up a contact]

Customer:

• Id
• Fields that make up a customer
• ICollection Contacts

Supplier:

• Id
• Fields that make up a supplier
• ICollection Contacts

Partner:

• Id
• Fields that make up a partner
• ICollection Contacts

Warehouse:

• Id
• Fields that make up a partner
• ICollection Contacts

etc... Currently the best I can do is create a ContactBase, then a contact per parent, and that adds an FK per parent to the database model. And that approach just seems overly complicated, causes code bloat (if a contact is truly is identical every time) and adds fields and un-needed indexes to the database.

Thanks

[ajcvickers]

From our best understanding this looks like an example of mapping interfaces with polymorphic associations, which is tracked by #757