#ER model

Question

Answer should be 1:1 isn't it ? Please Clear If i am wrong.

Consider a business rule such as “Each department is manged by atmost one employee”?

What is the cardinality from employee to the department?

• A. $1:1$
• B. $\text{1 : m}$
• C. $\text{m : 1}$
• D. $\text{m : n}$

Comments

The answer could be a or b with total participation on department side and partial at emp side.

Answer 1

"Each department is managed by atmost one employee"

BUT one employee can manage more than one department.

So the cardinality from employee to department should be 1:m.i.e. one to many.

Comments

How did you conclude that one employee can manage more than one department ?

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it is not mentioned that how many departments an employee can manage. So it cud be anything. Here m could be zero or 1 or greater than 1.

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@junaid yes we cannot conclude from the given statment.

 

Therefore it could be 1:1 or 1:m

 

Am i right ?

Answer 2

The answer is option-B. 1:1 cannot be the answer as they have not stated that "each employee manages atmost one dept"!

Answer 3

1:m seems to be a more appropriate answer as for a particular employee there can be 0 or atmost 1 department.