Re: pre-MED
pre-MED
От:
David Fetter <david@fetter.org>
Дата:
Folks, Please find enclosed a WIP patch to add the ability for functions to see the qualifiers of the query in which they're called. It's not working just yet, and I'm not sure how best to get it working, but I'd like to see this as part of 8.4, as SQL/MED is just way too ambitious given the time frame. Any tips, hints, pointers, etc. would be much appreciated. Also, PL/Perl shouldn't be the only language to have this capability. How might we add similar capabilities to PL/PythonU and PL/Tcl? To the rest of the PLs? Would it make any sense to have it in SQL language functions? Cheers, David. -- David Fetter http://fetter.org/ Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter Skype: davidfetter XMPP: david.fetter@gmail.com Remember to vote! Consider donating to Postgres: http://www.postgresql.org/about/donate
Re: pre-MED
От:
David Fetter <david@fetter.org>
Дата:
On Wed, Oct 29, 2008 at 09:40:00AM -0700, David Fetter wrote:
> Folks,
>
> Please find enclosed a WIP patch to add the ability for functions to
> see the qualifiers of the query in which they're called. It's not
> working just yet, and I'm not sure how best to get it working, but I'd
> like to see this as part of 8.4, as SQL/MED is just way too ambitious
> given the time frame.
>
> Any tips, hints, pointers, etc. would be much appreciated.
>
> Also, PL/Perl shouldn't be the only language to have this capability.
> How might we add similar capabilities to PL/PythonU and PL/Tcl? To
> the rest of the PLs? Would it make any sense to have it in SQL
> language functions?
Please find attached a patch which works in PL/Perl, the work having
been done by Andrew (RhodiumToad) Gierth. It's not clear to me how
this would be generally surface-able to SQL, though. Any ideas?
CREATE OR REPLACE FUNCTION show_qual()
RETURNS TEXT
LANGUAGE plperl
AS $$
return $_QUAL->{qual_string};
$$;
postgres=# SELECT * FROM show_qual() s(a) where a like '%';
a
------------------
(a ~~ '%'::text)
However, there are little lacunæ like this:
SELECT * FROM show_qual() s(a)
WHERE A NOT IN (
SELECT 'foo' UNION ALL SELECT 'bar'
);
a
------------------------
(NOT (hashed subplan))
Cheers,
David.
--
David Fetter http://fetter.org/
Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter
Skype: davidfetter XMPP: david.fetter@gmail.com
Remember to vote!
Consider donating to Postgres: http://www.postgresql.org/about/donate
