How does Oracle determine a table as key-preserved or not?
804267Dec 19 2010 — edited Dec 19 2010I tried joining employees and departments in HR schema. Normally, departments is not key-preserved in the join operation. But I've arranged in the view so that each department has exactly one employee, so that dept_no may become the key for the join. But still, it said "cannot modify non key-preserved table". Any hints? does the joining type (left or right or inner or outer) affect the mechanism on how Oracle determine which are key-preserved and which are not? thanks.