Hi Rich
> -----Original Message-----
> From: pgsql-general-owner@postgresql.org [mailto:pgsql-general-owner@postgresql.org] On Behalf Of Chris Travers
> Sent: Mittwoch, 7. Dezember 2016 17:12
> To: Postgres General <pgsql-general@postgresql.org>
> Subject: Re: [GENERAL] When to use COMMENT vs --
>
> On Dec 7, 2016 5:07 PM, "Karsten Hilbert" <Karsten.Hilbert@gmx.net <mailto:Karsten.Hilbert@gmx.net> > wrote:
> >
> > On Wed, Dec 07, 2016 at 07:57:54AM -0800, Rich Shepard wrote:
> >
> > > I have used '-- ' to enter comments about tables or columns and am
> > > curious about the value of storing comments in tables using the COMMENT key word.
> > > When is the latter more appropriate than the former?
> >
> > "--" only means "comment" to SQL code (such as in scripts).
> > PostgreSQL itself simply ignores it.
> >
> > OTOH, using "comment on ... is ..." tells PostgreSQL to _store_ a
> > comment on a database object for later retrieval.
> >
>
> This also means that tools like pg_autodoc can include it as part of the generated documentation.
All of the relevant differences have been mentioned by previous posters. IMHO the fact mentioned by Chris Travers that
commentson objects included in the database can be used by tools to generate the documentation is probably the most
important(besides their being persisted). As a matter of fact we have integrated this feature to extract comments to
generatethe DB documentation in our internal MediaWiki based wiki.
If you are interested in more details on that, including additional reasons why it is a good idea to use "comments on"
insteadof comments in the source code, you may have a look at this presentation:
http://www.schmiedewerkstatt.ch/documents/04-publications/integrating_postgresql_documentation_in_3rd_party_applications_handout_pdfa.pdf
Bye
Charles
> > Karsten
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