Re: [DOCS] Confusing Trigger Docs.

On Wed, Nov 22, 2023 at 10:31:25AM +0100, Laurenz Albe wrote:
> I agree that the paragraph you are trying to improve needs it.
> 
> I am not sure about that last sentence you added:
> 
>   The modification of
>   <varname>EXCLUDED</varname> columns has similar interactions.
> 
> How do you modify an EXCLUDED column?  Are you talking about a BEFORE
> INSERT trigger?  Reading the original text, I get the impression that
> it means "the behavior is obvious if you modify a column that is used
> with EXCLUDED in the DO UPDATE clause, but it can also happen if that
> column is not user with EXCLUDED".
> 
> Perhaps you should omit that sentence for clarity.

I think I found out what it trying to say by looking at the INSERT
manual page:

        Note that the effects of all per-row <literal>BEFORE
        INSERT</literal> triggers are reflected in
        <varname>excluded</varname> values, since those effects may
        have contributed to the row being excluded from insertion.

I modified the attached patch to explain this since it is not really the
same as modifying the actual row.  Does that add any value?  If not,
let's remove it.

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EDB                                      https://enterprisedb.com

  Only you can decide what is important to you.