Horton

Re: PostgreSQL vs SQL/XML Standards

Chapman Flack <chap@anastigmatix.net>

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From: Chapman Flack <chap@anastigmatix.net>
To: Alvaro Herrera <alvherre@2ndquadrant.com>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2019-03-07T16:48:32Z
Lists: pgsql-hackers 
On 3/7/19 10:08 AM, Alvaro Herrera wrote:
> I just pushed this one to pg12 only: 
>> xmltable-xmlexists-passing-mechanisms-3.patch

Thanks!

> I removed the words "first appears in SQL:2006" from the new doc
> paragraph; we used to have similar phrases scattered here and there but
> were removed years ago, on the grounds that only the most recent version
> is relevant (I couldn't find the commit, though).

In case there are similar qualifiers in the other patches (especially
the -docfix one, there are several), while respecting that general
principle, I would offer that there might be an argument for bending
it some here ...

... one of the main things challenging intuition and expectation in the
SQL/XML part of the standard is that there were radical changes to the
'XML' data type and the underlying data model between :2003 and :2006,
and most of what's in PostgreSQL was implemented to :2003 and still
conforms to that. (Being therefore, already, a bit of an exception
to the "only the most recent version is relevant" principle.)

So there could be good reason here to call out the distinctions when
they matter here, even if in other areas of the doc the practice is
not to call them out.

-Chap

Commits

  1. Improve documentation about our XML functionality

  2. Improve documentation about our XML functionality.

  3. Add volatile qualifier missed in commit 2e616dee9.

  4. Fix crash with old libxml2

  5. Fix minor deficiencies in XMLTABLE, xpath(), xmlexists()

  6. Fix the BY {REF,VALUE} clause of XMLEXISTS/XMLTABLE

  7. doc: Update README.links

  8. XPath fixes: