Re: Unique ID - again

Hello Alex, Thursday, February 12, 2004, 11:00:41 AM, you wrote: A> I'm using usual md5(microtime()); to create IDs, but now I've encountered a A> problem with that. I need to create explicitly 6 digit unique A> number(decimal). Yes, I know I can use for/while loop to fill a string with A> digits, but is it ABSOLUTELY sure that the random will never return same A> number when seed is microtime()? It is very important as the number will A> identify a bank transfer... If the data is so important - why are you restricting it to a 6 digit key? You should ideally use the uniqid() function perhaps with a combined lcg entropy at the end. That will give you a 13 character long unique id - or md5 it for a 32 character one (see the manual for examples). A> Is there any other way than checking with all previous IDs? Or some MySQL A> function to do this for me? For something so important I would use (a) a longer unique ID and (b) I'd still run a SQL check to see if the ID has been already used or not. A simple MySQL count will bring that result back very quickly. -- Best regards, Richard mailto:rich@launchcode.co.uk