Re: Doc BUG and/or Change Request: Include Postgres's system columns in reserved words in docs, Chnage to previx sytem colums with 2 underscores?

On Tue, Oct 3, 2017 at 6:13 AM, Euler Taveira <euler(at)timbira(dot)com(dot)br> wrote:

> 2017-10-02 22:30 GMT-03:00 dan d <dano2k3(at)hotmail(dot)com>:
> > Npgsql.PostgresException (0x80004005): 42701: column name "cmax"
> conflicts
> > with a system column name
> >
> > My first step was to google "Postgres Reserved Words" will eventually
> get
> > you to Appendix C in the doc but not mention about any system columns,
> url
> > for help page:
> >
> > https://www.postgresql.org/docs/9.6/static/sql-keywords-appendix.html
> >
> The title is clear: *SQL* Key Words. It is not *PostgreSQL* Key Words.
> BTW, system columns are documented [1].
>

​That's a bit unconvincing since there are words on that table that are not
marked as being reserved in any of the three​ SQL standard columns.

​Its user-error that an error message clearly indicating "system column
name" prompted a search for reserved words instead of "system columns". ​

The main distinction here is that "cmax" is a valid identifier expect when
used as a table column name (you can, for instance, name columns of CTEs
cmax) due to it already being in use. Given the clarity of the error
message and the fact that this is first I've seen the particular complaint
in many years of monitoring these lists, I'd say trying to add system
columns to the listing of reserved words in the interest of
"comprehensiveness" doesn't outweigh the complexity that would be
introduced explaining how it differs from other reserved words.

I wouldn't be opposed to adding a sentence and cross-reference link to the
system columns page and pointing out that specific column names are also
already reserved for system use.

​David J.
​