At 05:08 PM 29/05/2004 +0000, you wrote:

> > It's a serious flaw in design to try to work around concurrency
>protection
> > in the way you are trying to do it. It doesn't work; and you are
>risking
> > unpredictable logical corruption. (Logical corruption means bad
>data that
> > isn't detected by the engine).
> >
> > Helen
>
>Hi Helen,
>
>Basically, the design flaw is in the missing UNIQUE CONSTRAINT of the
>(supplierid, invoicenumber) pair, isn't it?

That depends on the design requirements. If your invoices must always have
a 1:1 correspondence the supplier invoice then supplierid, supplierinvoice
is enough of a unique constraint. If you can split one supplierinvoice
across multiple sales invoices then you need more.

Helen