Consider a relational table with a single record for each registered student…

GATE · 2011 · CS · Computer Science & IT

Consider a relational table with a single record for each registered student with the following attributes:

Registration_Num: Unique registration number for each registered student
UID: Unique identity number, unique at the national level for each citizen
BankAccount_Num: Unique account number at the bank. A student can have multiple accounts or joint accounts. This attribute stores the primary account number.
Name: Name of the student
Hostel_Room: Room number of the hostel

Which of the following options is INCORRECT?

A.
BankAccount_Num is a candidate key
B.
Registration_Num can be a primary key
C.
UID is a candidate key if all students are from the same country
D.
If S is a super key such that S ∩ UID is NULL then S ∪ UID is also a superkey

Attempted by 810 students.