PostgreSQL : Accessing tables owned by another user - postgresql

Question

As a Superuser, I have created two roles in Postgres on the same schema:
read_only_with_create_view
read_write
Then I created two users from each role:
read_only_with_create_view_user
read_write
Now any new views created by read_only_with_create_view_user cannot be accessed by read_write_user as the owner for views is different (read_only_with_create_view_user).
So what is the way to access all new views by read_write_user?
I want everything created by one user to be accessible to another user.
Steps I followed:
CREATE ROLE read_only_role WITH
NOSUPERUSER INHERIT NOCREATEDB NOCREATEROLE NOREPLICATION VALID UNTIL 'infinity';
GRANT CONNECT ON DATABASE mydb to read_only_role;
GRANT USAGE,CREATE ON SCHEMA myschema TO read_only_role;
GRANT SELECT ON ALL TABLES IN SCHEMA myschema TO read_only_role;
GRANT SELECT ON ALL SEQUENCES IN SCHEMA myschema TO read_only_role;
CREATE USER read_only_with_create_view_user
WITH PASSWORD '*****'
in ROLE read_only_role;
-- Now created new views using this role. That means read_only_with_create_view_user is owner of those views.
-- Creating new read-write role.
CREATE ROLE rw_role WITH
NOSUPERUSER INHERIT NOCREATEDB NOCREATEROLE NOREPLICATION VALID UNTIL 'infinity' IN ROLE read_only_role;
GRANT CONNECT ON DATABASE mydb to rw_role;
GRANT USAGE ON SCHEMA myschema TO crn_rw_role_qa;
GRANT ALL PRIVILEGES ON ALL TABLES IN SCHEMA myschema TO rw_role;
GRANT ALL PRIVILEGES ON ALL SEQUENCES IN SCHEMA myschema TO rw_role;
CREATE USER read_write_user
WITH PASSWORD '*****'
in role rw_role;
After login with read_write_user, when I try to access new views created by read_only_with_create_view_user, I get this error:
ERROR: permission denied for relation view_name
********** Error **********
ERROR: permission denied for relation view_name
SQL state: 42501

Answer 1

You can set a role as a member of another role:
GRANT read_only_with_create_view_user TO read_write_user;
More info here.
EDIT
It will never work as you expect. See your current user schema:
Role read_write_user will cannot access objects owned by read_only_with_create_view_user simply because both don't have any relationship. To make this works as you expect you can reassign objects ownership to an "upper" level role, in this case: read_only_role (because everybody is a member of this role). But be warned that it will no longer be a read-only role.
You can do one of the following:
--Connected as read_only_with_create_view_user
CREATE VIEW my_view AS SELECT 1;
--Assign ownership to top-level role
ALTER VIEW my_view OWNER TO read_only_role;
Or you may prefer this approach:
--Connected as read_only_with_create_view_user
--Change current user to read_only_role
SET role = read_only_role;
--Create a view...
CREATE VIEW my_view AS SELECT 1;
--Turn back to read_only_with_create_view_user
RESET role;
If you prefer to do all at once you can reassign ownership of objects owned by read_only_with_create_view_user to your top-level role in just one command:
REASSIGN OWNED BY read_only_with_create_view_user TO read_only_role;
Finally, if you don't want to break your read-only rule you can also, of course, give permission directly to the object.
-- As read_only_with_create_view_user, execute the following:
CREATE VIEW my_view_2 AS SELECT 1;
GRANT SELECT ON my_view_2 TO read_write_user