In a one-to-many relationship, where is the foreign key typically located?

• A. The foreign key resides on the many side referencing the one side.
• B. The foreign key resides on the one side referencing the many side.
• C. There is no foreign key in such a relationship.
• D. Both sides have independent primary keys with no foreign keys.

Answer: (A)

In a one-to-many relationship, the foreign key is placed in the table that represents the many side, pointing to the primary key of the one side. This setup lets each row on the many side reference exactly one row on the one side, while the one side can be linked to many rows on the many side. For example, a customer can have many orders, so the orders table includes a customer_id that references customers(id). This arrangement preserves the directional link from many to one and enforces referential integrity. Putting the foreign key on the one side would not reflect the typical one-to-many structure, and having no foreign key (or having both sides without a foreign key) would fail to establish the necessary relationship.