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(at)momjian(dot)us> https://momjian.us
EDB https://enterprisedb.com

Only you can decide what is important to you.