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

The function of a primary key in a database is to ensure that each entry can be distinctly recognized. A primary key serves as a unique identifier for each record in a table, meaning that no two rows can have the same primary key value. This uniqueness is essential for maintaining data integrity and preventing duplicate entries, which can lead to confusion and inaccuracies in data management.

Primary keys also enable efficient data retrieval and updates because they allow for the rapid identification of specific records. In relational databases, they play a crucial role in establishing relationships between tables—although that is primarily a function of foreign keys, the primary key relationship is foundational. Thus, the correct answer highlights the importance of a primary key in providing uniqueness and facilitating the organized structure of the database.