Jochem Maas wrote:

> Lester Caine wrote:
>
>>I'm having a number of giggley little problems which are causing agro a
>>few times a week across some sites while some never have the problem at all.
>>
>>The one that was spotted today is quite simple. Get ID from generator,
>>Add ticket with that ID, then process ticket.
>>
>>"INSERT INTO TICKET ( TICKET_ID, TICKET_REF, TICKET_NO, OFFICE, ROOM,
>>STAFF_ID, INIT_ID, CALLER_ID, APPLET )
>>VALUES ( $ticid, 'NOW', (SELECT COALESCE(MAX(TICKET_NO)+1, 1) FROM
>>CURRENT_DAY
>>WHERE OFFICE = $office AND TICKET_NO BETWEEN 0 AND 9999),
>>$office, 0, 0, 0, 0, ' ' )";
>>
>>I know that the MAX(TICKET_NO)+1 is not very safe, but the script seems
>>to be getting run TWICE as I get TWO ID's, but the same TICKET_NO with
>>an almost identical 'NOW'.
>>
>>Anybody any ideas what can be happening. Is it possible that PHP is
>>running a script twice with two different transactions, from the same
>>browser (IE of cause) and the second run does not see the commit of the
>>first run? If that makes sens? I can't explain these occasional
>>duplicates any other way, as once the ticket is added the user gets a
>>'clear ticket before adding a new one' and also the Add Ticket button is
>>not present on the page that Add Ticket goes to!
>
> it sounds like 2 different insertions (via 2 different requests) where
> the transactions are overlapping and the results of the one that started first
> is not being seen by the one start second... I really recommend a generator
> for the TICKET_NO.

That would not help - I'd STILL get two records just with two different
TICKET_NO's
I dropped the generator because of problems getting it reset to '0' at
the start of each day - it just was not happening in some offices so
they were ringing up and saying 'We haven't started at 1, somethings not
working!' - Things would be fine without customers :)

--
Lester Caine - G8HFL
-----------------------------
L.S.Caine Electronic Services - http://home.lsces.co.uk
Model Engineers Digital Workshop -
http://home.lsces.co.uk/ModelEngineersDigitalWorkshop/
Treasurer - Firebird Foundation Inc. - http://www.firebirdsql.org/index.php