How can i get this constraint in a ER Diagram?
Question
How can I get the third rule (the bold one) in an ER:
- A Teacher can help many Students and a Student gets help from many Teachers.
- A Teacher can lead many Students but a Student can be led by only one Teacher.
- The Teacher can't help the Student whose he is leading ."
Maybe something like this:
1 answers
solution1
0 2020-01-04 20:32:32
You need do add a constraint between your Help and Lead tables. Make sure the TeacherId - StudentID couple (?) are not in both tables.
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