This is a part of hospital diagram.
Each nurse can be assigned to different wards on different days of the week so a nurse must be supervised by another one who is assigned to the same ward on the same day of the week as the nurse or the nurse may be supervised by different nurses on different days of the week, but both the nurse and the supervisor nurse must be assigned to the same ward on the same day in which the supervision takes place.
I thin the entity is
ward(WardNO, WardName) , nurse (staffNo,Name, WarsNo)
and tell me the degree and participant of relation
can anyone please help me..
this is the picture. we must make some change into two entity (ward and nurse).
so can you please help me..
answered Dec 17, 2011 at 08:24 AM
Raj is right, you need to add a some sort of event tracking table. Your new diagram has no capability for transactional data or time-tracking. A ward shift table solves it elegantly. Your diagram should not have the self-reference of nurse to their supervisor, because that relationship is indirect or incidental. The nurses are assigned to the ward, and the supervising nurse is assigned to the ward. For any given day, a nurse and supervising nurse can be matched by the fact that they are both related to the same ward-shift instance.
What may have happened is your user-base gave you requirements in user language, which often looks at what they see day-to-day. The user does not see the difference between first-level and second-level relationships.
By relating supervisors and nurses directly, you'll be creating a maintenance nightmare.
answered Dec 17, 2011 at 12:43 PM