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On Wed, Jun 25, 2008 at 12:12 PM, Rimantas Liubertas <rimantas / gmail.com>
wrote:

> <...>
> >  If my DB is a model of real world entities as it
> > should be then there should be a unique indentifier for said entities
> which
> > means I shouldn't have to number them just because.
> >
> > In other words I am using necessary table elements as keys.
>
> The problem with "real world" unique identifiers is that even if they
> stay uniqui they
> _may_ change. The worst part it that they do change, even those you though
> would
> never ever possible change.
> Surrogate keys do not have this problem. They may have other problems,
> but it is worth it,
> imho.
>
> Regards,
> Rimantas
> --
> http://rimantas.com/
>
>
I'm curious as to when and why it matters if a primary key is mutable or
not.  As long as it is still unique and any necessary side-effects are
handled either by the app or the DBMS.

-- 
"Hey brother Christian with your high and mighty errand, Your actions speak
so loud, I can't hear a word you're saying."

-Greg Graffin (Bad Religion)

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