Re: Initially deferred constraints

From: DeanB <deanbrown3d_at_yahoo.com>
Date: Tue, 9 Jun 2009 06:41:52 -0700 (PDT)
Message-ID: <d7b13eaa-73b1-421c-8d6f-65413ab164bb_at_z5g2000vba.googlegroups.com>

On Jun 8, 5:24 pm, Robert Klemme <shortcut..._at_googlemail.com> wrote:
> On 08.06.2009 21:42, DeanB wrote:
>
> > On Jun 8, 2:38 pm, DeanB <deanbrow..._at_yahoo.com> wrote:
> >> On Jun 8, 12:35 pm, ddf <orat..._at_msn.com> wrote:
> >>> On Jun 8, 10:16 am, dean <deanbrow..._at_yahoo.com> wrote:
> >>>> Can anyone explain to me when a constraint can be deferred, but not
> >>>> initially deferred? My understanding is that initially deferred does
> >>>> not do its check until the close of a transaction, but I am not sure
> >>>> what NOT initially deferred means.
>
> DEFERRABLE INITIALLY IMMEDIATE basically means that the constraint may
> be deferred but is not at the moment.
>
> http://download.oracle.com/docs/cd/B19306_01/server.102/b14200/clause...
>
> > This statement:
>
> > set constraints all deferred;
>
> > alters all constraints that are deferrable (whether they are immediate
> > or not) to be deferred until the transaction is committed. However, if
> > a check is NOT defined as deferrable, then that check is not deferred
> > with the statement above, and the check can never temporarily be
> > allowed to fail.
>
> > The set constraints statement is reset on either commit or rollback of
> > the transaction.
>
> There are other ways of changing this as well:
>
> http://download.oracle.com/docs/cd/B19306_01/server.102/b14220/data_i...http://download.oracle.com/docs/cd/B19306_01/server.102/b14220/data_i...http://download.oracle.com/docs/cd/B19306_01/server.102/b14220/data_i...
>
> Kind regards
>
>         robert
>
> --
> remember.guy do |as, often| as.you_can - without endhttp://blog.rubybestpractices.com/

Thanks Robert - that is a very useful online book. -Dean Received on Tue Jun 09 2009 - 08:41:52 CDT