In the table Employee, each row contains data about an employee. The primary key is Empno. The attribute Empdeptno is a foreign key referring to the department number (Deptno. of the table Department.
8. Which of the following columns of the table Department is a foreign key?
A) Deptno
B) Deptname
C) Deptcity
D) Deptmgr
9. Which of the following columns is not a foreign key?
A) Projno in table Project
B) Projmgr in table Project
C) Prstno in table Projstaff
D) Prstempno in table Projstaff
10. If the combination Prstno, Prstempno is chosen as the primary key for table Projstaff, setting Prstno to null in some row would be:
A) A violation of the entity integrity rule
B) A violation of the referential integrity rule
C) A violation of the entity integrity rule and of the referential integrity rule
D) None of the above