What do foreign keys represent in database design?

In database design, foreign keys serve as a reference to the primary key of another table, establishing a relationship between the two tables. They specifically point to a unique identifier in another table, which allows for the association of data across different entities within the database. This relationship enhances data integrity and ensures that the data remains consistent, as it enforces a link between related records.

The use of foreign keys is essential for creating relational databases because they help maintain referential integrity, ensuring that relationships between records in different tables are preserved. By necessitating that the value in the foreign key column matches an existing value in the primary key column of the referenced table, foreign keys prevent orphan records and maintain the logical connections between entities.

While foreign keys do relate to the attributes of entities and the relationships between them, their primary function is to serve as a direct reference to another entity's primary key, making them critical for relational database structure. Thus, the essence of a foreign key is its role as a reference point, capturing the linkage necessary for relational integrity within the database.