Which HTTP method updates only specified fields of an existing resource and is not guaranteed to be idempotent depending on implementation?

Which HTTP method updates only specified fields of an existing resource and is not guaranteed to be idempotent depending on implementation?

• A. PATCH
• B. GET
• C. PUT
• D. POST

Answer: (A)

Partial updates to a resource use PATCH. It updates only fields you specify, leaving everything else alone. Because the patch document and the server’s interpretation can vary, the same PATCH request isn’t guaranteed to be idempotent—reapplying it could yield different results depending on implementation. That combination—targeted, partial changes and potentially non-idempotent behavior—fits the description given. GET is a read operation and does not modify the resource. PUT replaces the entire resource with the provided payload and is designed to be idempotent (reapplying the same update yields the same result). POST typically creates a new resource or triggers an action and is not idempotent by default.

Partial updates to a resource use PATCH. It updates only fields you specify, leaving everything else alone. Because the patch document and the server’s interpretation can vary, the same PATCH request isn’t guaranteed to be idempotent—reapplying it could yield different results depending on implementation. That combination—targeted, partial changes and potentially non-idempotent behavior—fits the description given.

GET is a read operation and does not modify the resource. PUT replaces the entire resource with the provided payload and is designed to be idempotent (reapplying the same update yields the same result). POST typically creates a new resource or triggers an action and is not idempotent by default.