On Tue, Jul 03, 2012 at 01:32:14PM +0200, Paul van Helden scratched on the wall:
> Hi,
>
> Is this correct? Should update triggers not only fire for actual changes? I
> have a large table with a column which contains all NULL values except for
> 4. I expected an UPDATE table SET column=NULL to only fire 4 triggers,
> except it fires for every row.
The statement "UPDATE table SET column=NULL" updates every row in the
table. The fact that some rows may already have a NULL in that
column is not important.
If you only want the trigger to fire for non-NULL rows, you need to
update only the non-NULL rows:
UPDATE table SET column=NULL WHERE column IS NOT NULL;
As for sqlite3_changes() returning 0, that doesn't sound right unless
you're checking inside the trigger.
-j
--
Jay A. Kreibich < J A Y @ K R E I B I.C H >
"Intelligence is like underwear: it is important that you have it,
but showing it to the wrong people has the tendency to make them
feel uncomfortable." -- Angela Johnson
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