Posted by "Richard Lynch" on 10/25/05 20:53

On Tue, October 25, 2005 4:01 am, Denis Gerasimov wrote:
> I am in a need of GUID generator but it seems that PHP doesn't have
> this as
> a built-in feature.

There is some discussion here you may find useful:

http://www.php.net/uniqid

> I really need "true" unique identifiers - md5() hash is not OK because
> of
> the "birthday paradox".

If you already have a database connection you can simply use a
sequence (or auto_increment in MySQL)

But that assumes you are willing to have predictable IDs, which you
might not.

> Can anyone recommend a way for solving this trouble?

You could use md5() and track every ID you hand out in a UNIQUE column
in a db, and simply generate another random md5() if you happen to run
into a duplicate.

The probability that you'd generate too many duplicate random md5()s
in a row for performance to be an issue is pretty small, if you
already have database activity going on.

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