title: Oracle SQL: Concern About Barred Relationships
body: <p>I have recently learned about “barred relationships” when developing an ERD through the Oracle Academy service. The course gave the following definition of a barred relationship: “A relationship that participates in an entity’s unique identifier” I understand how this works in the context of resolving a M:M relationship by creating an intersection entity and having the UID of that entity come from the originating relationships. My question is: Can a barred relationship occur in an instance where there is no intersection entity, or are barred relationships reserved for intersection entities?</p>