Question

An alternate key is ________.

• A. Another name for the primary key
• B. A unique identifier besides the primary key
• C. A relationship between two tables
• D. A synonym for a tuple

Answer 1

The Correct Option is B

In database management, an alternate key refers to a unique identifier other than the primary key. This concept is crucial because:

1. The primary key is used to uniquely identify records in a table. 
2. An alternate key offers another way to uniquely identify records, ensuring data integrity and enabling efficient querying when the primary key is not ideal for certain operations.

Given the options, the correct answer is clearly A unique identifier besides the primary key, distinguishing it from other options which do not align with the purpose of an alternate key in database systems.

Answer 2

An alternate key is a unique identifier besides the primary key.

Additional Context:

• Candidate key not selected as primary key
• Still maintains uniqueness constraint
• Example: In students table:
• Primary Key: student_id
• Alternate Key: email or roll_number

Correct Answer: (2) A unique identifier besides the primary key.