bskool bloggin: ER 2 ? found what he thinks is a typo in ER 3. Fixing his numbering to reflect the ER 3, he says:
In ER Excercise #3 the answer to question #1 states that advisor, which is the 1-M relationship between professor and student needs to be represented by a table, while position, which is the associative entity between professor and department does not need to be represented by a table. This seems contrary to our rule that M-M relationships, entity types, and associative entities are the only things we respresent as tables.
This is correct as far as what we emphasized in class. If you review the E-R modeling slides carefully, Slide 9 indicates that the specific instance Mike points out is a case where we would use a table to represent the relationship. This case will not play a role in the exam. Our general rule will still hold.