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The Co-operative Oracle Users' FAQ
http://www.jlcomp.demon.co.uk/faq/ind_faq.html
"VC" <boston103_at_hotmail.com> wrote in message
news:31e0625e.0401260623.1d635fbd_at_posting.google.com...
>
> The constraint is right there, in the statement itself:
>
> update t1 set amount=amount-80
> where (select t1.amount+t2.amount from t1 join t2 on t1.id=t2.id) > 0;
>
That's not a constraint, that's just a simple condition.
The following statement works just as well on your original
dataset (and I suspect it would do the same thing on all the
commercial RDBMSs):
update t1 set amount=amount-1000
where (select t1.amount+t2.amount from t1 join t2 on t1.id=t2.id) > 0;
I think the point you are really making isn't about
serializability, it's about commercial databases failing
to implement some features of generic constraints.
Received on Mon Jan 26 2004 - 09:38:32 CST
