>From: vegivamp@stripped [mailto:vegivamp@stripped] On Behalf Of Johan De
>Sent: Friday, January 21, 2011 1:22 AM
>To: Anthony Pace
>Cc: Michael Dykman; mysql.
>Subject: Re: best way to have a unique key
>I have to say, something similar was my first thought, too - you never
>mention uuid in your original post. As already stated, uuid() should be a
>Universal Unique IDentifier. It's afaik a random 128-bit number; given the
>space to choose from it should be rather unique. I have to admit that I'm
>not entirely confident about that myself, either, though: as Pratchett put
>it, one-in-a-million chances tend to pop up nine times out of ten.
[JS] A UUID (what Microsoft calls a GUID) is based in part on the MAC address
of the generating device. Since MAC addresses are supposed to be unique across
the known universe, so should a UUID.
Global Information Incorporated
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>The code should have bits for handling duplicate primaries regardless of the
>method used to generate it, tough, so there's no reason to not do it. Having
>two subsequent UUID() calls generate pre-existing numbers seems to me to be
>likely in the same way as having Bush return his dirty oil dollars to Irak.
>On Thu, Jan 20, 2011 at 8:10 PM, Anthony Pace
>> Dude, come on. I know that all primary keys have to be unique; however, I
>> was obviously referring to the use of uuid over auto incrementation.
>> On 1/20/2011 1:36 PM, Michael Dykman wrote:
>>> It is axiomatic in the relational model that a primary must be unique.
>>> This is not a quirk put forth by your current employer. Neither
>>> MySQL nor any other RDBMS will allow you to establish a primary key
>>> that is not unique.
>>> - michael dykman
>>> On Thu, Jan 20, 2011 at 1:32 PM, Anthony
>>>> Due to certain reasons, the company I am doing business with has decided
>>>> that the primary key, for an orders table, be a unique key; however, I
>>>> like the possibility of it conflicting if moved to another machine.
>>>> What are some pitfalls of using a unique key, that is generated by a
>>>> side script, rather than by mysql?
>>>> What are the best ways to do this?
>>>> Please keep in mind this variable will also be displayed on the
>>>> Receipt, but again, since it's random, it doesn't have to mean anything.
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