Data and processes
Idempotency
In short and in plain language
Idempotency means the same call may arrive more than once. The result does not change.
So an order is not created twice. This holds even if the reply got lost and the sender tried again.
Usually each operation gets its own unique key. The receiving program stores it and recognises it.
Definition
Idempotent means the same call may arrive more than once without changing the result — an order is not created twice if the response was lost and the sender retried. This is usually implemented with a unique key per operation that the receiving system stores and recognises.