Re: Preferred method in creating primary key

Brian,

I've read many of your posts here over the years, and you too Daniel; I respect you both..

I must say, in my opinion, although I've been tempted to often create constraints as defferrable initially immediate, I've never done so...I recognize the theoretical

benefits, but in a world of legacy systems, the lack of documentation, and the turnover
that occurs in the IT world..I tend to go with Brian's opinion..notwithstanding Daniel, your
completely valid point with respect to foreign keys, I still fret that we can't count on the
application to use the database correctly and developers to write the code to handle

deferrable constraints..

In my designs that I send to production, the PK is the PK..no delay; however, my favorite
tool is still SQL*Plus so maybe I'm a bit of a dinosaur..

As such, I tend to write all of my constraints as immediate and let the analysts cope :)

As Brian said, its only my opinion.

Daniel Morgan wrote:

> Brian Peasland wrote:
>
> > It makes some sense that this index is not unique since the constraint
> > checking is deferred until you commit. Before the commit, you are
> > allowed to insert all the duplicate key values you want, but you must
> > remove them before you commit. If the index were UNIQUE, then the
> > duplicate key values would not be allowed.
> >
> > Personally, I've hated deferrable constraint checking since it was
> > introduced. We put constraints in the database so that the business
> > rules on the data are adhered to. This is especially important since we
> > don't trust the application to validate those business rules for us. So
> > why do we decide to throw out those business rules "temporarily"? It
> > just seemed to me to be a short cut for doing things right the first
> > time. Maybe it's just my opinion though...
> >
> > Cheers,
> > Brian
> >
> > <snipped>
>
> I agree with respect to primary key and unique constraints. They make no logical
> sense. But they are a logical extension when applied to Foreign Keys.
>
> --
> Daniel Morgan
> http://www.outreach.washington.edu/extinfo/certprog/oad/oad_crs.asp
> damorgan_at_x.washington.edu
> (replace 'x' with a 'u' to reply)
Received on Wed Aug 13 2003 - 21:10:46 CDT