Thanks David. I’ve thought about the hierarchy you mentioned but the hierarchy can change and I need to capture it as it was when the data was generated.
I should have pointed out in my last response that I was wondering if the performance of the pk index on work_session would be better if my primary key was (customer_id, work_session_id) or if (work_session_id, customer_id) will be fine. Customer_id will be repeated quite a bit in the table but work_session_id should be unique across the whole table.
I answered that in the original response...for PKs to operate most efficiently the most selective attribute should come first.
David J.
