Re: conditional rule not applied - Mailing list pgsql-general

From Seb
Subject Re: conditional rule not applied
Date
Msg-id 87bph8otya.fsf@kolob.sebmags.homelinux.org
Whole thread Raw
In response to conditional rule not applied  (Seb <spluque@gmail.com>)
List pgsql-general
On Wed, 30 Dec 2009 20:04:51 -0600,
Seb <spluque@gmail.com> wrote:

> On Wed, 30 Dec 2009 19:39:15 -0600,
> Seb <spluque@gmail.com> wrote:

> CREATE RULE footwear_nothing_upd AS
>> ON UPDATE TO footwear DO INSTEAD NOTHING; CREATE RULE
>> footwear_newshoelaces_upd AS ON UPDATE TO footwear WHERE NEW.sl_name
>> <> OLD.sl_name AND OLD.sl_name IS NULL DO INSERT INTO shoelaces
>> (sh_id, sl_name) VALUES(NEW.sh_id, NEW.sl_name);

> I think my error is in the test expression, which doesn't deal
> properly with the null value, so correcting:

> CREATE RULE footwear_nothing_upd AS
>     ON UPDATE TO footwear DO INSTEAD NOTHING;
> CREATE RULE footwear_newshoelaces_upd AS
>     ON UPDATE TO footwear
>     WHERE NEW.sl_name IS DISTINCT FROM OLD.sl_name AND OLD.sl_name IS NULL
>     DO
> INSERT INTO shoelaces (sh_id, sl_name)
>     VALUES(NEW.sh_id, NEW.sl_name);

> However, could a more direct and robust test for an inexistent record
> in 'shoelaces' be made?

Any ideas? I'm not sure this is the best way to test whether the record
to update corresponds to a inexistent record in 'shoelaces'. Thanks.


--
Seb

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