On 30-06-2020 05:23, David Carr wrote:
> So I was under the impression, wrongly it seems, that within a BEFORE
> UPDATE trigger that I could do the following:
> IF (NEW.<field> IS NULL) THEN
> ...<do some action>
> where if <field> is not provided in the SQL command, that it would be
> NULL. But it seems I am wrong here, where <field> simply contains the
> value that already exists in the record if not given in the query.
> I suspect I made the wrong assumption by following the way legacy code
> was done using the same syntax above on a BEFORE INSERT trigger, where
> <field> IS null.
> I have read these articles:
> however with regards to the second link, what I want to do here is not
> test for change, but rather test if the SQL provided in the
> query/command specifies this parameter. Is there a [easy] way to do this?
> To give context, I am setting timestamps if particular fields have
> changed, and I want to perform this in triggers - so that it is always,
> and reliably, done - as opposed to the code explicitly setting the value.
There is no option to do that. You can only detect that the new version
OLD.column. You cannot detect whether the value was explicit set through