Re: Is the use of VARCHAR(256) as Primary Keys preferred in Oracle?

"Niall Litchfield" <niall.litchfield_at_dial.pipex.com> wrote:
> "Pablo Sanchez" <pablo_at_dev.null> wrote in message
> news:Xns92C9EFAF939C3pingottpingottbah_at_209.242.64.107...
> > "Jim Kennedy" <kennedy-family_at_attbi.com> wrote in
> news:8o%B9.73293$1O2.5806
> > @sccrnsc04:
> >
> > > a surrogate key is an arbitrary key (eg a sequence). A natural key
> > > is
> one
> > > that is naturally part of the data (eg in the US the social security
> number
> > > for people)
> >
> > As a side note, SSN's are intended to be unique but are not for a
> > variety of reasons.
> > --
> > Pablo Sanchez, High-Performance Database Engineering
> > http://www.hpdbe.com

>
> A marvellous example of the problems of 'natural keys'.

How so?

Xho

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