use the time(with milliseconds) . Why not??
I don't understand when you say "how unique". You increment the last generated key through code right. So it will be.
I prefer not to use milli/nano seconds, but you are right, I will increment the last generated key. I misunderstood what you wrote before. My doubt was whether I could generate #NNNN whiteout querying for the last inserted record.
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