Is Your UUID Truly Unique?

Checking if your "universally unique identifier" is actually unique by comparing it to a database of other UUIDs is like asking if your fingerprints are unique by pressing them against everyone else's fingers. The whole point of UUIDs is that they're generated to be mathematically unique without needing to check a central registry. With 2^128 possible combinations, you have better odds of winning the lottery while being struck by lightning... twice... on Mars.