Re : Update columns in same table from update trigger? - Mailing list pgsql-general

From Pablo Romero Abiti
Subject Re : Update columns in same table from update trigger?
Date
Msg-id 1311432583.29230.YahooMailNeo@web161620.mail.bf1.yahoo.com
Whole thread Raw
In response to Re: Update columns in same table from update trigger?  (Alban Hertroys <dalroi@solfertje.student.utwente.nl>)
Responses Re: Re : Update columns in same table from update trigger?
List pgsql-general
Hi Alban, thank's for your reply. I already changed it as you wrote, but I'm still having the problem that the trigger won't execute unless the value specified for idcolor in table warehouse does exist. Shouldn't the trigger execute BEFORE the update process?
Regards,
Pablo



De : Alban Hertroys <dalroi@solfertje.student.utwente.nl>
À : Pablo Romero Abiti <pabiti@yahoo.com>
Cc : "pgsql-general@postgresql.org" <pgsql-general@postgresql.org>
Envoyé le : Samedi 23 Juillet 2011 3h59
Objet : Re: [GENERAL] Update columns in same table from update trigger?

On 22 Jul 2011, at 22:02, Pablo Romero Abiti wrote:

> The problem I'm facing is that the trigger before update won't execute if there isn't a row with idcol=3 in the table warehouse.
>
> Here's my code:
>
> CREATE OR REPLACE FUNCTION update_warehouse() returns "trigger" AS '
>    declare idcolmaestro float:=0;
>    BEGIN
>      select into a idcolor1 from color_eq where idcolor2=old.idcolor;

You didn't declare 'a'. Perhaps you meant to use idcolmaestro?

>      if a is null then

Try 'if NOT FOUND' here instead.

>          a=old.idcolor;
>      end if;
>
>      new.idcolor=a;
>      return new;
>  END;
> ' LANGUAGE 'plpgsql' VOLATILE;

I'd probably change this code a bit so that the assignment to idcolor only takes place if a value with idcolor2=old.idvalue was found:

    if FOUND then
        new.idcolor := a;
    endif

    return new;

That saves a few unnecessary CPU cycles.

Alban Hertroys

--
The scale of a problem often equals the size of an ego.



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