Re: Theoretical Basis for SELECT FOR UPDATE

peter.koch.larsen_at_gmail.com wrote:
> Tony Andrews skrev:
> > The TTM version would make it impossible to print the intermediate
> > total (which would be 10 higher than it should be).
>
> Would it now?
>
> update account set bal=bal+10 where ac_no=123,
> call print_total_balance_for_all_accounts,
> update account set bal=bal-10 where ac_no=456;
>
> (Notice commas have replaced semicolons).

Yes, it would: your syntax is not valid. The commas are not merely an syntactic alternative to semi-colons, they are semantically different too: they indicate that the two updates are to be treated as a single DML statement with no implicit ordering. You can't insert a call to procedure between the two updates - that is the point of having this syntax! Received on Tue Oct 04 2005 - 12:32:04 CEST