Hi,

I would like to write a before update trigger that will
check the value of a column and if the value is satisfied, I
would like to stop the execution flow of the command without
error.
Is it possible? if so, how can Ido that?

Thanks,

Think the other way round: if values IS NOT satisfied then do something else
don't bother.
Use old_ and new_ row variable to get values for columns.

CREATE TRIGGER "Xxx" BEFORE UPDATE
ORDER 1 ON "TableName"
REFERENCING OLD AS old_row NEW AS new_row
FOR EACH ROW /* WHEN( search_condition ) */
BEGIN
if old_row.col_Val <> 'whatever' then
// do something here
end if;
END;

Clive

"a.sahan" wrote in message news:4b5ed07f.3882.1681692777 (AT) sybase (DOT) com...

Thank you for your reply. However, it can be misunderstood.
My goal is to stop execution flow, not only trigger itself.

For example,
I would like to update a record in a table but if one of the
columns is equal to zero, I would like to cancel update
command. I can't check this before command execution. The
only way is to detect it in trigger or another way.

If I understand your request correctly, ROLLBACK TRIGGER might be your
friend, i.e. smething like (untested)

CREATE TRIGGER "Xxx" BEFORE UPDATE
ORDER 1 ON "TableName"
REFERENCING NEW AS new_row
FOR EACH ROW
BEGIN
if new_row.col_Val = 0
message '0 value detected: Revoke action' to log;
rollback trigger;
end if;
END;

This will undo the update itself.
Note: This might work not well if used within nested triggers - cf. the
docs (and the [ WITH raiserror-statement ] option).


HTH
Volker


Am 27.01.2010 09:18, schrieb a.sahan:

Thank you. That's what I'm looking for. and in case of
recursion, can it be resolved by moving rollbAck command
into After-Update Trigger?