Which one of the following option is INCORRECT?
A. BankAccount_Num is candidate key
B. Registration_Num can be a primary key
C. UID is candidate key if all students are from the same country
D. If S is a superkey such that S∩UID is NULL then S∪UID is also a superkey
Answer:B
Which one of the following option is INCORRECT?
A. BankAccount_Num is candidate key B. Registration_Num can be a primary key C. UID is candidate key if all students are from the same country D. If S is a superkey such that S∩UID is NULL then S∪UID is also a superkey