HELP needed with an ERD
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How would I draw an ERD for a situation like this:
professors can teach the same course in several semesters, and each offering must be recorded.
If I know that:
Professorss can have an SSN and courses can have a courseid.
Any helpful suggestions are welcome.
professors can teach the same course in several semesters, and each offering must be recorded.
If I know that:
Professorss can have an SSN and courses can have a courseid.
Any helpful suggestions are welcome.
We'd be happy to help, but we don't want to do all the work for you. Can you show us what you have so far?
To help you out, four entities should be sufficient to track the information in your post.
To help you out, four entities should be sufficient to track the information in your post.
Here is your data dictionary:
The link table is needed as you cant basically have a many to many relationship between staff and courses. It just doesnt work like that.
In my example, one Staff can have many TaughtCourse (one staff member can teach many groups) and each Course may be taught many times to many different groups. However, one group can only be a part of oe course.
So its a ONE staff <- may teach -> MANY TaughtCourse
and ONE ToughtCourse < - can have -> MANY Course
Staff
SSN (Primary Key)
Other staff data
Course
CourseID (Primary Key)
Other Course Data
TaughtCourse (this is important, you need a link table)
CourseID (Foreign Key)
SSN (Foreign Key
Other details (e.g when, where, notes)The link table is needed as you cant basically have a many to many relationship between staff and courses. It just doesnt work like that.
In my example, one Staff can have many TaughtCourse (one staff member can teach many groups) and each Course may be taught many times to many different groups. However, one group can only be a part of oe course.
So its a ONE staff <- may teach -> MANY TaughtCourse
and ONE ToughtCourse < - can have -> MANY Course
Last edited by jbennet : Nov 23rd, 2008 at 12:12 pm.
Master of puppets Im pulling your strings - blinded by me, you cant see a thing. Master! Master!
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If i am helpful, please give me reputation points.
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