[AccessD] Access and SQL Server

D,RFC :-)

-- 
Stuart

On 2 Mar 2011 at 11:22, Jim Dettman wrote:

> John,
> 
> <<ohhhh don't go there!!!>> 
> 
>   Ah why not? ;)
> 
> <<PKs and unique indexes are NOT the same thing.>>
> 
>  I would not agree with that.  In a relational context, a PK in a
>  relation
> by it's very definition would form a unique index.
> 
> << Having an auto number PK does not in any way relieve 
> the developer from the responsibility of analyzing for a field or set
> of fields which ensure uniqueness and setting a unique index on those
> fields.>>
> 
>   Yes because it's a misnomer to call a auto number a PK or even a
>   surrogate
> key.  It may be labeled as such, but it certainly does not perform the
> function of one. 
> 
>   As we have discussed in the past, auto numbers are simply pointers
>   or
> tags.
> 
> Jim.
> 
> 
> -----Original Message-----
> From: accessd-bounces at databaseadvisors.com
> [mailto:accessd-bounces at databaseadvisors.com] On Behalf Of jwcolby
> Sent: Wednesday, March 02, 2011 09:40 AM To: Access Developers
> discussion and problem solving Subject: Re: [AccessD] Access and SQL
> Server
> 
>  >My question would be, how in your app do you prevent a patent from
>  being
> entered more then once?
> 
> ohhhh don't go there!!!
> 
> PKs and unique indexes are NOT the same thing.  Having an autonumber
> PK does not in any way relieve the developer from the responsibility
> of analyzing for a field or set of fields which ensure uniqueness and
> setting a unique index on those fields.
> 
> That "response" is one usually received from very junior DBAs.
> 
> John W. Colby
> www.ColbyConsulting.com
> 
> On 3/2/2011 8:04 AM, Jim Dettman wrote:
> > Debbie,
> >
> >    I bet you use a natural key in your app without even thinking
> >    about it
> as
> > such.  My question would be, how in your app do you prevent a patent
> > from being entered more then once?
> >
> > Jim.
> >
> > -----Original Message-----
> > From: accessd-bounces at databaseadvisors.com
> > [mailto:accessd-bounces at databaseadvisors.com] On Behalf Of Debbie
> > Elam Sent: Tuesday, March 01, 2011 09:18 PM To: Access Developers
> > discussion and problem solving Subject: Re: [AccessD] Access and SQL
> > Server
> >
> > I do as well.  I have run into problems every time I have used
> > (developed by others) databases with natural keys.  I will NEVER use
> > them for the following reasons:
> >
> > 1.  Real data can ALWAYS change.  I do not care how immutable it is
> > supposed to be, data changes.  Just ran into a problem in reports
> > out of a CRM database.  One magazine has changed names 3 times in 8
> > years. They still want info tracked together, but the natural key of
> > a short code based on the name has changed (sigh). 2.  Real Data is
> > subject to typos.  Even the best typist can realize a problem
> > happened after data has been entered.  Fix it and the relationship
> > is crap without cascade updates. 3.  Real data is never as unique as
> > you may think.  This is why natural keys usually evolve into
> > compound keys.  Had a patent database that used docket numbers as a
> > natural key.  As they supported additional countries, they added
> > country.  As addendum were added to the patent, refines were added. 
> > Now this 3 field compound key was a nightmare to work with.  To top
> > it off, you guessed it, problem 1 reared it's head too.  Rare
> > occurrence, but in a database of almost 100,000 patents, it probably
> > occurred a few times a month.  Headache every time it happened.
> >
> > Debbie
> >
> > On 3/1/2011 1:12 PM, jwcolby wrote:
> <<snip>>
> 
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