Re: Oracle DBA Studio, almost useful

From: Niall Litchfield <n-litchfield_at_audit-commission.gov.uk>
Date: Mon, 24 Nov 2003 15:49:58 -0000
Message-ID: <3fc228a6$0$9394$ed9e5944_at_reading.news.pipex.net>

"Jarmo" <jarmo_at_jarmo.com> wrote in message

news:3fc21b57$0$13345$ed9e5944_at_reading.news.pipex.net...

> "Niall Litchfield" <n-litchfield_at_audit-commission.gov.uk> wrote in message
> news:3fc1e353$0$13348$ed9e5944_at_reading.news.pipex.net...
> > "Jarmo" <jarmo_at_jarmo.com> wrote in message
> > >
> > > I suspect that it's complaining about the CONSTRAINT "" which it
> inserted
> > > when I requested that EMPLOYEEID had to be unique. Disregarding the
> fact
> > > that the tool is bugged in allowing me to specify an illegal
combination
> > of
> > > options, why must I provide a 'constraint'? And what would it be?
Why
> > > isn't it sufficient to simply state that the column must contain
unique
> > > values?
> >
> > Because you need to create a unique constraint to enforce uniqueness.
>
> Thanks for replying Niall. Presumably this constraint is just some kind
of
> textual identifier so that when Oracle detects a duplicate value in the
> associated column(s) it can raise an exception containing that identifier
> and hence your software can identify which column(s) were in error.
Sounds
> reasonable though I've never come across a situation in which anything
other
> than a keyed field (or group of key fields) needed to be unique so one
could
> readily infer the cause from the key violation without need for any
> additional information.

Yes although you can have other types of constraint than just uniqueness, for example check.

-- 
Niall Litchfield
Oracle DBA
Audit Commission UK

Received on Mon Nov 24 2003 - 16:49:58 CET