Path: dp-news.maxwell.syr.edu!spool.maxwell.syr.edu!drn.maxwell.syr.edu!news.maxwell.syr.edu!postnews.google.com!g43g2000cwa.googlegroups.com!not-for-mail
From: "Marshall  Spight" <marshall.spight@gmail.com>
Newsgroups: comp.databases.theory
Subject: Re: Database design, Keys and some other things
Date: 1 Oct 2005 07:52:31 -0700
Organization: http://groups.google.com
Lines: 25
Message-ID: <1128178351.116353.101840@g43g2000cwa.googlegroups.com>
References: <1127614484.101580.227050@z14g2000cwz.googlegroups.com>
   <1127664075.629746.215390@g47g2000cwa.googlegroups.com>
   <1127699280.011880.214310@g49g2000cwa.googlegroups.com>
   <1127743579.517124.175180@f14g2000cwb.googlegroups.com>
   <1127753043.539728.165710@g49g2000cwa.googlegroups.com>
   <1127753335.528946.79940@f14g2000cwb.googlegroups.com>
   <1127914716.567410.120030@f14g2000cwb.googlegroups.com>
   <1127954152.036051.278410@z14g2000cwz.googlegroups.com>
   <1127973815.601819.70770@g43g2000cwa.googlegroups.com>
   <1127993601.169825.146750@g47g2000cwa.googlegroups.com>
   <1128006072.359969.299630@g47g2000cwa.googlegroups.com>
   <1128014625.276871.42390@g14g2000cwa.googlegroups.com>
   <1128057088.233421.297080@z14g2000cwz.googlegroups.com>
   <433cf1d0$0$11072$e4fe514c@news.xs4all.nl>
   <1128091149.160408.124430@g49g2000cwa.googlegroups.com>
   <433d595a$0$11068$e4fe514c@news.xs4all.nl>
NNTP-Posting-Host: 24.4.95.46
Mime-Version: 1.0
Content-Type: text/plain; charset="iso-8859-1"
X-Trace: posting.google.com 1128178356 19544 127.0.0.1 (1 Oct 2005 14:52:36 GMT)
X-Complaints-To: groups-abuse@google.com
NNTP-Posting-Date: Sat, 1 Oct 2005 14:52:36 +0000 (UTC)
In-Reply-To: <433d595a$0$11068$e4fe514c@news.xs4all.nl>
User-Agent: G2/0.2
X-HTTP-UserAgent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.5) Gecko/20041107 Firefox/1.0,gzip(gfe),gzip(gfe)
Complaints-To: groups-abuse@google.com
Injection-Info: g43g2000cwa.googlegroups.com; posting-host=24.4.95.46;
   posting-account=s2xCFw0AAAD2mIwYYHAqjdsecwG0axmW
Xref: dp-news.maxwell.syr.edu comp.databases.theory:33834

mAsterdam wrote:
> Marshall Spight wrote:
> >>
> >>There is an important difference. Unless we are talking about
> >>that specific "*some*" database, the VIN is /not/ a surrogate key in
> >>the database at hand.
> >
> > So you are saying that whether something is a surrogate key
> > or not is determined within the context of a specific database?
>
> Just as the key-ness of something is.
> Is column x a key for table y?
> The question only makes sense within the context
> of a specific database.

Okay. It strikes me, though, that this leads directly
to a refutation of the idea that there's any essential
difference between the industry standard external
identifier and the database-specific surrogate key:
it's a matter of context merely, and not anything
intrinsic to that data, or how it is managed.


Marshall