Re: trigger/rule question - Mailing list pgsql-sql

From Christoph Haller
Subject Re: trigger/rule question
Date
Msg-id 4275DD8C.EF29E7A1@rodos.fzk.de
Whole thread Raw
In response to trigger/rule question  (Enrico Weigelt <weigelt@metux.de>)
List pgsql-sql
Enrico Weigelt wrote:
> 
> * Christoph Haller <ch@rodos.fzk.de> wrote:
> 
> Hi,
> 
> > I assume this still refers to
> > [SQL] RULE for mtime recording
> > from last Friday.
> 
> ehm, yeah. I forgot that I've already asked this stuff ...
> hmmpf. seems I'm not getting younger ;-)
> 
> <snip>
> > I gave it another thought and
> > I am now having something which seems to work.
> > The trick is interpose a view to avoid the
> > rule recursion:
> 
> <big_snip />
> 
> correct me if I'm wrong:
> 
> you dont let the application write to the actual storage table, but
> instead to a view, which a modified write to the actual storage, where
> also the reads get their data from.

Exactly. 
> 
> okay, that's really an idea worth to think about :)
> 
> insert should work the same way. but how to implement delete ?
> (the application should only see one table, so in our case the view).

Exactly. 
> if we user "DO INSTEAD", we wont get anything to delete (AFAIK), so
> we cannot intercept here. the only chance seems to leave out "INSTEAD"
> and live with duplicate data.

No. What's wrong with (referring to my previous post) 

CREATE OR REPLACE RULE joo_delete 
AS ON DELETE TO joo_view 
DO INSTEAD 
DELETE FROM joo 
WHERE bar = OLD.bar ; 

DELETE FROM joo_view WHERE bar = '...' ; 

works perfectly for me 

Or did I miss something here? 
Regards, Christoph 

> 
> Did I miss anyting ?
> 
> cu
> --
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