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

The primary purpose of a primary key in a database is to uniquely identify each record in a table. A primary key provides a unique identifier for every entry, ensuring that no two records can have the same key value. This uniqueness is crucial for maintaining data integrity and allows for efficient data retrieval and management. By ensuring that every record can be distinctly referenced, it enables operations such as updates, deletions, and linking to files without ambiguity.

This unique identification also facilitates relationships with other tables in a relational database, but that function relies on the existence of a primary key. In contrast, options that suggest enforcing security or ensuring data redundancy do not accurately capture the essence of what a primary key is designed to accomplish.