Which relationship type best describes an order that contains multiple order items?

Which relationship type best describes an order that contains multiple order items?

• A. One-to-One
• B. Many-to-Many
• C. One-to-Many
• D. Many-to-One

Answer: (C)

A one-to-many relationship is demonstrated here: a single order can have multiple order items, while each order item is linked to only one order. This matches how orders are structured in most systems—you can add many items to one order, but a given item line belongs to a specific order. In a database, this is implemented with a foreign key in the OrderItem table that references the Order. One-to-one would mean only one item per order, which isn’t the case. Many-to-many would allow items to appear in many orders, which isn’t the standard way to model individual line items. Many-to-one would imply many orders share the same item, which doesn’t align with each line item belonging to a single order.

A one-to-many relationship is demonstrated here: a single order can have multiple order items, while each order item is linked to only one order. This matches how orders are structured in most systems—you can add many items to one order, but a given item line belongs to a specific order. In a database, this is implemented with a foreign key in the OrderItem table that references the Order.

One-to-one would mean only one item per order, which isn’t the case. Many-to-many would allow items to appear in many orders, which isn’t the standard way to model individual line items. Many-to-one would imply many orders share the same item, which doesn’t align with each line item belonging to a single order.