On Tue, Jan 16, 2001 at 12:58:41PM +0100, Mirko Zeibig wrote:
> On Mon, Jan 15, 2001 at 07:54:26PM -0800, Adam Haberlach wrote:
> > I've got the following procedure...
> > 
> > DROP FUNCTION "blank_referring_devices" ();
> > CREATE FUNCTION "blank_referring_devices" () RETURNS opaque AS
> > '
> > BEGIN
> >     EXECUTE ''UPDATE t_device SET accountid=NULL WHERE accountid ='' 
> >     || quote_literal(OLD.accountid);
> > END;
> > '
> > LANGUAGE 'plpgsql';
> > 
> > DROP TRIGGER "t_account_blank_devrel" ON "t_account";
> > CREATE TRIGGER "t_account_blank_devrel" BEFORE DELETE ON "t_account" 
> > FOR EACH ROW EXECUTE PROCEDURE "blank_referring_devices" (); 
> 
> Hello Adam,
> of course I do not know what you want exactly, but why do you need EXECUTE 
> for this?
> 
> BEGIN
>                UPDATE t_device 
>                                SET accountid=NULL 
>                                WHERE accountid=quote_literal(OLD.accountid);
> END;

        This seems to be what I want, but how does this differ from the 'EXECUTE'
syntax, which I find is not yet in released versions of Postgres?  I'll try
this out...

> should do as well. Maybe you are even better of with a foreign key
> constraint, where you may include 'on delete set null' as well.
> 
> alter table T_DEVICE 
>                       add constraint FK_T_DEVICE_ACCOUNTID 
>                       foreign key (ACCOUNTID) 
>                       references T_ACCOUNT(ACCOUNTID)
>                       on delete set null;

        Yep, this is the other option.  This database wasn't really designed
with any kind of formal referential integrity, so I felt that the more
ad-hoc stuff I was doing above would be more flexible.

-- 
Adam Haberlach            |A cat spends her life conflicted between a
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http://www.newsnipple.com |fish and an equally deep, passionate, and
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