Which of the following options are correct regarding these three keys (Primary Key, Super Key, and Candidate Key) in a database?

Category: SQLWhich of the following options are correct regarding these three keys (Primary Key, Super Key, and Candidate Key) in a database?
Editor">Editor Staff asked 2 years ago

Which of the following options are correct regarding these three keys (Primary Key, Super Key, and Candidate Key) in a database?
I. Minimal super key is a candidate key
II. Only one candidate key can be a primary key
III. All super keys can be a candidate key
IV. We cannot find a primary key from the candidate key

  1. I and II
  2. II and III
  3. I and III
  4. II and IV
1 Answers
Editor">Editor Staff answered 2 years ago

Answer:

  1. I and II

Explanation: Candidate key in SQL is a set of fields that identify each record in a table uniquely. It is a super key with no repeated fields that means the minimal super key is a candidate key. A table can contain multiple candidate keys, but it can have only a single primary key. Therefore option A is the correct choice.