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CS422
assumption about movie rental

Author	Message
Urvashi Posts: 34	Posted 11:26 Jul 08, 2009 \| hello Professor, Are we assuming that a customer can rent the same movie more than one time ? because if this is the case then the many-to-many relationship table between videos and customer will have redundancy in its keys... thank you
cysun Posts: 2935	Posted 13:03 Jul 08, 2009 \| Urvashi wrote: hello Professor, Are we assuming that a customer can rent the same movie more than one time ? because if this is the case then the many-to-many relationship table between videos and customer will have redundancy in its keys... thank you Yes, a customer can certainly rent the same movie multiple times.
Urvashi Posts: 34	Posted 13:39 Jul 08, 2009 \| cysun wrote: Urvashi wrote: hello Professor, Are we assuming that a customer can rent the same movie more than one time ? because if this is the case then the many-to-many relationship table between videos and customer will have redundancy in its keys... thank you Yes, a customer can certainly rent the same movie multiple times. ok, so can a relationship attribute be made a key ? like, rental_date for rented_by relatinship table
cysun Posts: 2935	Posted 13:44 Jul 08, 2009 \| Urvashi wrote: cysun wrote: Urvashi wrote: hello Professor, Are we assuming that a customer can rent the same movie more than one time ? because if this is the case then the many-to-many relationship table between videos and customer will have redundancy in its keys... thank you Yes, a customer can certainly rent the same movie multiple times. ok, so can a relationship attribute be made a key ? like, rental_date for rented_by relatinship table A relationship doesn't have keys. If you feel like a relationship needs a key, then it probably should be an entity set.