Re: What is a surrogate identifier

"Cimode" <cimode_at_hotmail.com> wrote in message news:1174055929.671636.192510_at_e1g2000hsg.googlegroups.com...
> On Mar 16, 3:32 pm, "JOG" <j..._at_cs.nott.ac.uk> wrote:
> > I would also add in hindsight that the distinction between something
> > that identifies a proposition and something that identifies the
> > entities about which those propositions speak is an extremely
> > important distinction to make. I think this often gets confused,
> > generating confusion and miscommunication. Indeed I imagine this is
> > the very reason why Codd chose the term 'key' instead of 'identifier'
> > when it came to defining attributes which make a certain proposition
> > unique.
>
> >From Date's relational dictionnary
>
> surrogate key
>

> A single-attribute key with the property that its values serve
> solely as surrogates-hence the name-for the entities they stand for
> (in other words, they serve merely to represent the fact that the
> corresponding entities exist, and they carry absolutely no additional
> information or meaning).
>
> Hope this helps...
>

A surrogate key serves as a surrogate for a natural key. The word "entity" in the above is a possible source of confusion. Received on Fri Mar 16 2007 - 14:16:31 CDT