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@postgresql.org>
Date: 2019-06-01T12:53:35Z
Lists: pgsql-hackers 
On 05/31/19 16:04, Alvaro Herrera wrote:

> https://www.iso.org/standard/41528.html "XQuery Regular Expression
> Support in SQL"

Although I hadn't seen that particular document, I did see those in the
SQL spec and mention them in the wiki page [1].

I should point out that's also a conformance note in the new SQL/JSON
support [2], as the standard specifies XQuery regular expressions for
jsonpath's like_regex predicate, where we're applying POSIX ones
instead.

Doesn't change my thinking much ... I think we should support the
stuff. :) ... using a non-in-house-developed XQuery library to do it,
or better yet, a choice of non-in-house-developed XQuery libraries.

I still think the second idea I suggested on the wiki seems like the
most promising road map [3], though it'll involve a few preparatory
stops along the way.

-Chap



[1]
https://wiki.postgresql.org/wiki/PostgreSQL_vs_SQL/XML_Standards#XML_Query_regular_expressions

[2]
https://github.com/obartunov/sqljsondoc/blob/master/README.jsonpath.md#sqljson-conformance

[3]
https://wiki.postgresql.org/wiki/PostgreSQL_vs_SQL/XML_Standards#Proposal_2:_desugaring_to_calls_on_normal_extension_functions

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: