Re: Re: Create unique non-autoincrement key for700,000records?

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Sorry you are right. He said he wants each row to have an unique ID so 
AutoIncId+timestamp will satisfy it, But still i think that adding 
microseconds timestamp is better because it will be harder for potential 
hacker to guess.
-- 


S pozdravem
Ondøej Kulatý
---------------------
Winternet s.r.o.
odd. vývoje aplikací
tel. 585 209 132
www.winternet.cz

"Robert Cummings" <robert@xxxxxxxxxxxxx> pí¹e v diskusním pøíspìvku 
news:1229416450.9173.46.camel@xxxxxxxxxxxx
> On Tue, 2008-12-16 at 09:21 +0100, Ondrej Kulaty wrote:
>> I think he knows how to use it, he didn't show us a certain example where
>> and how he wants to use it, i just posted the way how i do generate an
>> unique identifier, if he use the first mentioned way -
>> AutoIncID+unix_timestamp - there can be a collision, when two users will
>> attempt to perform this task on the same id at the same time. yes, it's 
>> not
>> very probable but if you have system with many users it can happen
>
> No it's impossible. Auto increment guarantees a unique auto incremented
> ID. Adding the value returned by unix_timestamp() to this unique ID can
> only create unique sums since both the auto increment ID and the time
> are increasing. There cannot be a collision.
>
> Cheers,
> Rob.
> -- 
> http://www.interjinn.com
> Application and Templating Framework for PHP
> 



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