Re: sql DO in rule 9.0rc1
Re: sql DO in rule 9.0rc1
От:
Jeff Davis <pgsql@j-davis.com>
Дата:
On Thu, 2010-09-09 at 17:07 -0400, A.M. wrote:
> Is there a technical limitation which prevents DO from being used in rules or am I missing something with this?
>
> CREATE RULE test_update AS ON UPDATE TO test DO INSTEAD DO $$
> BEGIN;
> RAISE NOTICE 'hello';
> END;
> $$;
>
> Cheers,
> M
From the docs here:
http://www.postgresql.org/docs/9.0/static/sql-createrule.html
I see:
"Valid commands are SELECT, INSERT, UPDATE, DELETE, or NOTIFY."
And I assume that DO is a separate command that is not valid for a rule
such as this.
As a workaround, you can make a named function and do "SELECT
myfunction()" as the INSTEAD clause.
Regards,
Jeff Davis
Re: sql DO in rule 9.0rc1
От:
"Joshua D. Drake" <jd@commandprompt.com>
Дата:
On Fri, 2010-09-10 at 13:39 -0400, Merlin Moncure wrote: > IDK...functions do everything 'DO' does, and support returning data, > which is necessary to support RETURNING. Rules are already fairly > capricious and problematic and I doubt any proposal that doesn't fix > or work around their basic flaws will get much traction. Not to mention there have been talks of ripping them out all together. JD -- PostgreSQL.org Major Contributor Command Prompt, Inc: http://www.commandprompt.com/ - 509.416.6579 Consulting, Training, Support, Custom Development, Engineering http://twitter.com/cmdpromptinc | http://identi.ca/commandprompt
Re: sql DO in rule 9.0rc1
От:
"Joshua D. Drake" <jd@commandprompt.com>
Дата:
On Fri, 2010-09-10 at 13:39 -0400, Merlin Moncure wrote: > IDK...functions do everything 'DO' does, and support returning data, > which is necessary to support RETURNING. Rules are already fairly > capricious and problematic and I doubt any proposal that doesn't fix > or work around their basic flaws will get much traction. Not to mention there have been talks of ripping them out all together. JD -- PostgreSQL.org Major Contributor Command Prompt, Inc: http://www.commandprompt.com/ - 509.416.6579 Consulting, Training, Support, Custom Development, Engineering http://twitter.com/cmdpromptinc | http://identi.ca/commandprompt
Re: sql DO in rule 9.0rc1
От:
Tom Lane <tgl@sss.pgh.pa.us>
Дата:
"Joshua D. Drake" writes: > On Fri, 2010-09-10 at 13:39 -0400, Merlin Moncure wrote: >> IDK...functions do everything 'DO' does, and support returning data, >> which is necessary to support RETURNING. Rules are already fairly >> capricious and problematic and I doubt any proposal that doesn't fix >> or work around their basic flaws will get much traction. > Not to mention there have been talks of ripping them out all together. Yeah. Proposals to add inessential features to rules are probably not going to go far at the moment. What we need first is a design for fixing their fundamental issues, so that we can have some reason to think we're not going to just give up and rip 'em out :-( regards, tom lane
sql DO in rule 9.0rc1
От:
"A.M." <agentm@themactionfaction.com>
Дата:
Is there a technical limitation which prevents DO from being used in rules or am I missing something with this?
CREATE RULE test_update AS ON UPDATE TO test DO INSTEAD DO $$
BEGIN;
RAISE NOTICE 'hello';
END;
$$;
Cheers,
M
Re: sql DO in rule 9.0rc1
От:
Merlin Moncure <mmoncure@gmail.com>
Дата:
On Fri, Sep 10, 2010 at 1:30 PM, A.M. wrote: > On Sep 9, 2010, at 8:31 PM, Jeff Davis wrote: >> On Thu, 2010-09-09 at 17:07 -0400, A.M. wrote: >>> Is there a technical limitation which prevents DO from being used in rules or am I missing something with this? >>> >>> CREATE RULE test_update AS ON UPDATE TO test DO INSTEAD DO $$ >>> BEGIN; >>> RAISE NOTICE 'hello'; >>> END; >>> $$; >>> >>> Cheers, >>> M >> >>> From the docs here: >> >> http://www.postgresql.org/docs/9.0/static/sql-createrule.html >> >> I see: >> >> "Valid commands are SELECT, INSERT, UPDATE, DELETE, or NOTIFY." >> >> And I assume that DO is a separate command that is not valid for a rule >> such as this. >> >> As a workaround, you can make a named function and do "SELECT >> myfunction()" as the INSTEAD clause. > > Perhaps I should have posted to -hackers instead, but I was really wondering if there were some real technical limitation to having this implemented. Does "DO" have any sort of context which can be applied? It seems that NEW and OLD would have to be pushed into that context. IDK...functions do everything 'DO' does, and support returning data, which is necessary to support RETURNING. Rules are already fairly capricious and problematic and I doubt any proposal that doesn't fix or work around their basic flaws will get much traction. merlin
Re: sql DO in rule 9.0rc1
От:
"A.M." <agentm@themactionfaction.com>
Дата:
On Sep 9, 2010, at 8:31 PM, Jeff Davis wrote: > On Thu, 2010-09-09 at 17:07 -0400, A.M. wrote: >> Is there a technical limitation which prevents DO from being used in rules or am I missing something with this? >> >> CREATE RULE test_update AS ON UPDATE TO test DO INSTEAD DO $$ >> BEGIN; >> RAISE NOTICE 'hello'; >> END; >> $$; >> >> Cheers, >> M > >> From the docs here: > > http://www.postgresql.org/docs/9.0/static/sql-createrule.html > > I see: > > "Valid commands are SELECT, INSERT, UPDATE, DELETE, or NOTIFY." > > And I assume that DO is a separate command that is not valid for a rule > such as this. > > As a workaround, you can make a named function and do "SELECT > myfunction()" as the INSTEAD clause. Perhaps I should have posted to -hackers instead, but I was really wondering if there were some real technical limitation to having this implemented. Does "DO" have any sort of context which can be applied? It seems that NEW and OLD would have to be pushed into that context. Cheers, M
