Rand offers the high probability of scarcity in a finite dataset, but it doesn't guarantee uniqueness. And in an infinate dataset (which is, of course, only theoretical) using rand will result in an infinate number of duplications. Even in a small dataset, though highly improbable, there is no guarantee that rand wont return .984553 followed by .984553 within a few iterations. It's within the realm of possibility, even if unlikely.

If you don't want to use the unique user id module, perhaps you could use a combination of: Process ID, Time, and an in-loop counter. If you want to rely on rand, don't call the ID "unique". Call it "rare". Just because something is improbable doesn't mean it's unique. And why settle for scarcity in a situation where you require uniqueness, when it is truly not that difficult to develop a solution that provides what is actually needed?

Dave

"If I had my life to do over again, I'd be a plumber." -- Albert Einstein

In reply to Re: Re: Use time() to create unique ID by davido
in thread Use time() to create unique ID by Anonymous Monk

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