On Thu, Dec 21, 2000 at 05:50:43PM +0000, Oliver Elphick wrote:
> Mike Castle wrote:
> >On Thu, Dec 21, 2000 at 11:10:00AM +0100, Kaare Rasmussen wrote:
> >> - Sequences are not rollback'able.
> >
> >Did you mean SERIAL instead of sequence here?
> >
> >If so, why is no rollbackable an issue? All you should need is unique
> >numbers. Not necessarily exactly sequential numbers.
>
> For invoice numbers, it matters.
>
> Numbers missing from such a sequence are likely to provoke questions from
> auditors and taxmen; why borrow trouble?
What do you do on the following scenario:
Client 1 is placing an order, gets invoice #1.
Client 2 is simultaneously placing an order, and gets invoice #2.
Client 1 changes mind and cancels order. Invoice #1 is not used. Invoice
#2 is.
Client 3 comes along. Do they use invoice #1, out of order, or invoice #3?
I suppose of the assignment of the invoice number is set up in such a way
as it is the very last action performed just before the commit, you should
be able to ensure that indeed the situation of having to deal with a
rollback would never occur (outside of a system crash between assignment of
invoice and commit, and that could be explained to auditors).
[What happens in a paper world if a cup of coffee is spilt on some
invoices, and these precious items are thrown in the trash?]
mrc
-- Mike Castle Life is like a clock: You can work constantly dalgoda@ix.netcom.com and be right all the
time,or not work at all
www.netcom.com/~dalgoda/ and be right at least twice a day. -- mrc We are all of us living in the shadow of
Manhattan. -- Watchmen