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

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@interjinn.com> pí¹e v diskusním pøíspìvku news:1229416450.9173.46.camel@localhost... > 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 >