Re: inserting via "on insert" rule - Mailing list pgsql-general

From Peter Eisentraut
Subject Re: inserting via "on insert" rule
Date
Msg-id Pine.LNX.4.44.0309012326200.1206-100000@peter.localdomain
Whole thread Raw
In response to inserting via "on insert" rule  (Andreas Fromm <Andreas.Fromm@physik.uni-erlangen.de>)
Responses Re: inserting via "on insert" rule
Re: inserting via "on insert" rule
List pgsql-general
Andreas Fromm writes:

> I was thinking of defining a view "users" over "persons" which would let
> me retrive the list of useres. But How would I implement the rule for
> insertiung users? I tryed the following but NEW is not known where I
> want to use it:
>
> CREATE VIEW users AS
>     SELECT * FROM persons WHERE is_user(person.id) = TRUE;
>
> CREATE RULE insert_on_users AS ON INSERT
>     TO users DO INSTEAD
>         INSERT INTO persons SELECT * FROM NEW;

You can write

... DO INSTEAD INSERT INTO persons VALUES (NEW.col1, NEW.col2, ...);

> The other thing I don't know is how to enforce the aditional constraints
> that qualify as user when inserting to users. Of course I could do it on
> the application side, but I would like to have it on the database too.

CREATE RULE insert_on_users AS ON INSERT TO users
    WHERE is_user(NEW.id)
    DO ...

Read the chapter on rules in the documentation to learn more about this.

--
Peter Eisentraut   peter_e@gmx.net


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