Idempotent relation

Idempotent relations are ones where you can do the same thing multiple times, but you will always get the same answer. Think of it like baking cookies: if you mix up the ingredients in the same way, you will end up with the same batch of cookies each time, no matter how many times you do it. Idempotent relations help make sure that the same result is always produced, no matter how many times it is run through the same process.