Final answer:
Relational databases use foreign keys to represent relationships, which create a link between records in different tables.
Step-by-step explanation:
Relational databases represent relationships using foreign keys. A foreign key is a field in one table, which uniquely identifies a row of another table. The role of the foreign key is to enforce referential integrity within the database. For instance, in a database with tables for Students and Classes, the Classes table might have a column for student id that acts as a foreign key referencing the Students table. This establishes a link between each class record and the corresponding student record, illustrating the relationship between the data in both tables.