ISRO2018-52

Question

In $\text{E-R}$ model, $\text{Y}$ is the dominant entity and $\text{X}$ is subordinate entity

1.  If $\text{X}$ is deleted, then $\text{Y}$ is also deleted
2.  If $\text{Y}$ is deleted, then $\text{X}$ is also deleted
3.  If $\text{Y}$ is deleted, then $\text{X}$ is not deleted
4.  None of the above

Answer 1

Y is dominant entity : Strong entity

X is Subordinate entity : Weak entity

Strong entity connects weak entity by using identifying relationship so we generally prefer cascading effect.

If anything happens in dominant entity that is also reflected in Subordiante entity but vice versa is not true.

Employee < ===> Dependent ( Relationship <<is dependent>>)

If employee deleted its depedent tuple must be deleted.

Answer B

Answer 2

Here X is dependent on Y. So if Y is deleted its dependents also get deleted.