Re: What is a surrogate identifier

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... Received on Fri Mar 16 2007 - 15:38:49 CET