Role-Playing Dimensions

When the interviewer gives you a fact table with three date columns (order_date, ship_date, deliver_date), they are testing whether you create three dimension tables or one. The correct answer is one dim_date referenced three times. This is a role-playing dimension, and naming it unprompted shows Kimball-level fluency. The Schema the Interviewer Expects Your role-playing answer: 'Three foreign keys, all pointing to the same dim_date. Each one plays a different role: when ordered, when shipped, when delivered. The physical table is one. The logical usage is three. I do not create three separate date dimensions.' The interviewer is checking whether you understand that one physical dimension can serve multiple analytical roles. How to Narrate the Query in the Interview Demonstrate the query: