What is the primary purpose of a primary key in a database?

• A. Create data redundancy
• B. Ensure data integrity
• C. Facilitate data sharing
• D. Improve data retrieval

Answer: (B)

The primary purpose of a primary key in a database is to ensure data integrity. A primary key is a unique identifier for each record in a database table, which prevents duplicate entries and guarantees that each record can be accurately distinguished. This unique identification is essential for maintaining the integrity of the data, as it ensures that each record can consistently and reliably be referred to without confusion.

With a primary key in place, relationships between tables can also be established easily, allowing for the enforcement of referential integrity. This means that only valid data can be entered into related tables, further contributing to the overall reliability and accuracy of the database. In this way, the primary key plays a crucial role in the effective management of database information, helping maintain consistent data across all operations.