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One-to-one (1-1) relationship type in Common Data Service (CDS)

The only two types of relationships that are supported ) in Common Data Service (CDS) are One-to-many (1-N) / Many-to-one (N-1) and many-to-many (N-N). Would be great to finally have the ability to have a true one-to-one (1-1) relationship between two entities. Currently the workaround is two relationships, 1-N and N-1 between the two entities and have custom logic to populate the the lookups on each entity.

Status: New
Kudo Kingpin

I don't think there is intention to create one-to-one. The only way to deal with this is then creating a key. 


BTW I disagree that many-to-many relationship is working. You can't access the relationship anywhere in the model driven plus the view problem takes you to the default despite your pre-selected view. 

Solution Sage

Hi @Yahya, I'm not sure I understand both your comments... 1-1 with a key, alt key? That's just a unique index on an entity. N-N (out-of-the-box or custom with junction entity) does work...

Kudo Kingpin

Hi @EricRegnier ,



By key, I mean you can enforce entity A to have a unique record to entity B by creating a key in, for instance, entity A with the key bring the primary name together with the lookup record from the other entity. In this case then you hit the target that only 1 relationship occurs between 2 records from the 2 entities and no duplicates will occur. 


My 2 problems with many to many are:


Add existing will take you to default view despite that you have configured the subgrid to look up a specific view. It's then up to the user yo enter data correctly. This is a bug. 



Number 2 is that the many to many relationship is not accessible in business rules or process.