Stephan Szabo wrote:
>
> On Tue, 11 Dec 2001, Philip Warner wrote:
>
> > At 13:34 7/12/01 -0800, Stephan Szabo wrote:
> > >
> > >Well, the biggest thing I see on using alter table add constraint for
> > >foreign keys is the expense involved if you do it after the tables are
> > >populated.
> >
> > Is it really worse than loading the tables with the constraint in place?
>
> I'd say its better than while loading, but currently the check isn't
> performed at all I think, because the create constraint trigger
> statements are after data load and they don't check the data at all.
> At least that's how I remember it, I could be wrong.
You're not. This discussion came up a couple of times, and the answer is allways the same.
We don't want to define the constraints with ALTER TABLE because this means checking data on restore that
doesn'tneed to be checked at all (in theory). If he has a crash of a critical system and restores from a dump,
Ibet the farm that he wants it FAST.
Jan
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