A Key which is a set of one or more columns that can identify a record uniquely is called?
A. Natural key
B. Candidate key
C. Not Null key
D. Alternate key
Answer:A
A Key which is a set of one or more columns that can identify a record uniquely is called?
A. Natural key B. Candidate key C. Not Null key D. Alternate key
Explanation: A candidate key is a combination of attributes that can be uniquely used to identify a database record without any extraneous data. Each table may have one or more candidate keys. One of these candidate keys is selected as the table primary key.