Consider the relation Emp-Dept with SSn as key

Ename

SSn

EAddr

Dept. No

Dept. Name

Dept. Manager

SSn

 

Which of the following is (are) invalid operation(s)?

a) Inserting an employee without name and address

b) Inserting an employee with only SSn

c) Inserting a department with no employee

d) Inserting an employee without SSn