Re: inserting via "on insert" rule

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