Multiple choice

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

  1. Registration_Number: Unique registration number for each registered student
  2. UID: Unique Identity number, unique at the national level for each citizen
  3. BankAccount_Number: Unique account number at the bank. A student can have multiple accounts or joint accounts. This attributes stores the primary account number
  4. Name: Name of the Student
  5. Hostel_Room: Room number of the hostel Which of the following options is INCORRECT?

  1. BankAccount_Number is a candidate key

  2. Registration_Number can be a primary key

  3. UID is a candidate key if all students are from the same country
  4. If S is a superkey such that S UID $\cap$ is NULL then S $\cup$ UID is also a superkey
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In case two students hold joint account then BankAccount_Num will not uniquely determine other attributes.

Keep practicing — related questions