Subject: Re: Triggers on underlying tables of updatable views
To: Laurenz Albe <laurenz.albe@cybertec.at>, <pgsql-docs@lists.postgresql.org>
References: <163758281947.26190.10251137266467665332@wrigleys.postgresql.org>
 <2f54dbb7d59aacacbc4654b0bc56faaebe993e09.camel@cybertec.at>
From: Max Ziermann <max.ziermann@htw-dresden.de>
Message-ID: <3e14b477-40ce-4b6a-047a-9fea3843427c@htw-dresden.de>
Date: Mon, 22 Nov 2021 19:54:52 +0100
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Thanks for your reply.

Maybe I am missing an obvious point, but I don't think that's the case.
SQL example:


CREATE ROLE view_access;
CREATE TABLE data (a integer primary key);
CREATE VIEW data_view AS SELECT * FROM data;
GRANT SELECT, INSERT ON data_view TO view_access;

CREATE FUNCTION trig() RETURNS trigger AS $$
BEGIN
    RAISE NOTICE 'trig() executed as user=%', current_user;
    PERFORM COUNT(*) FROM data;
    RETURN new;
END
$$ LANGUAGE plpgsql;
CREATE TRIGGER trig AFTER INSERT ON data FOR EACH ROW EXECUTE FUNCTION
trig();


-- Executed by owner of view, data and trigger: (as expected) all ok
INSERT INTO data_view VALUES (1);

SET ROLE TO view_access;
-- Executed by view_access: fails
INSERT INTO data_view VALUES (2);


For the second INSERT, the trigger is called by the user performing the
insert instead of the user owning the table or the view.


Best Regards,

Max Ziermann

Am 22.11.21 um 16:41 schrieb Laurenz Albe:
> On Mon, 2021-11-22 at 12:06 +0000, PG Doc comments form wrote:
>> "Note that the user performing the insert, update or delete on the view must
>> have the corresponding insert, update or delete privilege on the view. In
>> addition the view's owner must have the relevant privileges on the
>> underlying base relations, but the user performing the update does not need
>> any permissions on the underlying base relations (see Section 41.5)."
>>
>> Could it be made more clear that triggers on a underlying table of an
>> updatable view are still executed with the permissions of the user
>> performing an insert/update/delete on the view?
> But that is not the case: that trigger will be executed with the permissions
> of the owner of the underlying table.
>
> Yours,
> Laurenz Albe
>