In a relational database, which statement best describes the role of a primary key?

In a relational database, which statement best describes the role of a primary key?

• A. To store large binary data.
• B. To enforce access control.
• C. To create a backup schedule.
• D. To uniquely identify each record in a table.

Answer: (D)

The primary role of a key in a relational database is to provide a unique, non-null identifier for every row in a table. This ensures each record can be distinguished from all others and can be reliably referenced by related tables through foreign keys, enabling accurate joins and data integrity across the database. Primary keys are typically indexed to speed up lookups, updates, and relationships. They’re not used for storing large binary data, handling access control, or scheduling backups, which are separate database functions.

The primary role of a key in a relational database is to provide a unique, non-null identifier for every row in a table. This ensures each record can be distinguished from all others and can be reliably referenced by related tables through foreign keys, enabling accurate joins and data integrity across the database. Primary keys are typically indexed to speed up lookups, updates, and relationships. They’re not used for storing large binary data, handling access control, or scheduling backups, which are separate database functions.