From: Bruce Momjian <bruce@momjian.us>
Message-Id: <200608261647.k7QGlMF04492@momjian.us>
Subject: Re: New XML section for documentation
In-Reply-To: <e431ff4c0608252337u4801cf34he200e57a3242661d@mail.gmail.com>
To: nikolay@samokhvalov.com
Date: Sat, 26 Aug 2006 12:47:22 -0400 (EDT)
CC: Peter Eisentraut <peter_e@gmx.net>,
	PostgreSQL-development <pgsql-hackers@postgresql.org>
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Nikolay Samokhvalov wrote:
> On 8/26/06, Peter Eisentraut <peter_e@gmx.net> wrote:
> > Bruce Momjian wrote:
> > > Validation
> > > ----------
> > > /contrib/xml2 has a function called xml_valid() that can be used in
> > > a CHECK constraint to enforce that a field contains valid XML.  It
> > > does not support validation against a specific XML schema.
> >
> > Then this is not validation but only checking for well-formedness.  The
> > xml2 README says so, in fact.
> 
> Exactly. contrib/xml2 mixes the term here, xml_valid() should be
> another function, that takes two types of data - XML value and
> corresponding XML schema - and validate the XML data. Actually, the
> latest version of SQL/XML standard includes such a function
> (XMLVALIDATE).

I understand, but do we want to break backward compatibility to rename
it?  We could create a xml_check, and keep xml_valid as a
single-argument function, and implement schema-checks as a two-parameter
function, but that seems odd too.

> If you decide to include the mentioning about contrib/xml2 to docs, I
> would suggest the patch for this module. The patch renames that
> function to xml_check() and adds xml_array() (issue from the current
> TODO). Or it's too late for 8.2?

Hard to say.  What does xml_array do?  We are more lenient about
/contrib additions after feature freeze, but it is pretty late.  Aren't
you working on updating the new XML syntax support in the backend?  Are
you done with that patch?

> Also, I would add a little introduction to XML terms (from XML
> standards) to this documentation section.

OK, but which terms.  I only see XML and XSLT, and I documented those on
first mention in the newest version.

-- 
  Bruce Momjian   bruce@momjian.us
  EnterpriseDB    http://www.enterprisedb.com

  + If your life is a hard drive, Christ can be your backup. +