In database management, what is the role of a foreign key?

The role of a foreign key in database management is to establish a relationship between two tables by linking to the primary key of another table. This connection allows for the enforcement of referential integrity, ensuring that every value of the foreign key in one table corresponds to a valid primary key in another table. This setup helps maintain consistency across the database by preventing orphaned records—those that reference a non-existent record in another table.

For instance, in a relational database where one table holds customer information and another holds order information, the order table may include a foreign key that references the customer’s primary key. This structure allows the database to ensure that each order is associated with an existing customer. By enforcing such relationships, foreign keys enable the development of complex queries and facilitate the organization of data in a meaningful way.