Sqlalchemy One-to-one, Store Foreign Key In Each Table?

I have a relationship that is one to one between cage codes and duns numbers. I have set up my relationship that looks like, where I store a ForeignKey on each of the respective ta

Solution 1:

I believe you only need to store one foreign key for a one-to-one relationship. See https://docs.sqlalchemy.org/en/13/orm/basic_relationships.html#one-to-one

You shouldn't lose any data access this way. If you remove the duns_id column from Cage, you now access the id by cage.duns.id instead of cage.duns_id.