Re: [ADMIN] How to execute my trigger when update certain columns

On Wed, 2002-08-14 at 13:09, Raymond Chui wrote:
> Let say I have a table has column1 and column2 and I made a trigger for
> after INSERT OR UPDATE for each row to execute procedure my_function.
>
> What I want is the trigger execute my_function only when column1 is
> insert or
> update, but not going to execute my_function when column2 is insert or
> update.

The trigger is executed unconditionally, so put the condition inside
my_function.

If it's an INSERT, column1 must be new, so:

IF TG_OP = ''INSERT'' OR
(TG_OP = ''UPDATE'' AND
(NEW.column1 != OLD.column1 OR
(NEW.column1 IS NULL AND OLD.column1 IS NOT NULL) OR
(NEW.column1 IS NOT NULL AND OLD.column1 IS NULL)
)
) THEN
...
END IF;

--
Oliver Elphick Oliver(dot)Elphick(at)lfix(dot)co(dot)uk
Isle of Wight, UK
http://www.lfix.co.uk/oliver
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