Subject RE: [firebird-support] Re: multiple inserts in trigger
Author Ross Ryding
Does anyone know how expensive it is to fire off 50 triggers on an update
that do a single insert to a table as oppose to inline code that tests for
50 cases and one trigger fired? Is firing a trigger in firebird lightweight
of heavy?


[] On Behalf Of Ross Ryding
Sent: Wednesday, July 11, 2007 9:52 AM
Subject: RE: [firebird-support] Re: multiple inserts in trigger

Ok, I broke each test off into a separate trigger and it works fine. This
does not make sense to me since it should be the same difference. In single
file many tests I am doing a After Update so the second fire of the UPDATE
trigger for the second field change should test the first value as no change
and thus skip it. I tried doing one as an insert command and the other as a
select command reducing the procedure just down to two tests and it still
hangs. When I do one at a time it inserts the record when I do two changes
with two tests in one trigger neither update the audit file.

Does this make sense to anyone?

I really thought I was smarter than this

-----Original Message-----
From: firebird-support@ <>
[mailto:firebird-support@ <>] On Behalf Of Sasha
Sent: Wednesday, July 11, 2007 7:59 AM
To: firebird-support@ <>
Subject: RE: [firebird-support] Re: multiple inserts in trigger

> I would have never thought of that, great idea and greatly
> appreciated. I
> assume that distinct understands the NULL state.
In a nutshell yes, but you must understand that if(a = b) will never return
true if either a or b is null and that's by design.
If you want to test for nulls you must rewrite it like this:

if ((a is null and b is null) or a=b) then -- your test condition might be
-- something
end else
-- something else

or simpler like this:

if (a is not distinct from b) then
something else

I think is [not] distinct was introduced in FB 2.0.0 so if you are running
earlier version you will not be able to use it, but you should check on



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