Postgres Views

SECURITY INVOKER indicates that the function is to be executed with the privileges of the user that calls it. That is the default. SECURITY DEFINER specifies that the function is to be executed with the privileges of the user that created it.

https://hevodata.com/learn/postgresql-stored-procedures/

Copy Table

CREATE TABLE users.chat as SELECT * FROM api.chat;

Create View

CREATE VIEW api.chat AS
 SELECT id,
    name,
    user_id,
    created_at
   FROM users.chat
  WHERE (user_id = ( SELECT users.id
           FROM public.users
          WHERE ((users.username)::text = CURRENT_USER)));

int to uuid

ALTER TABLE public.items ALTER COLUMN user_id SET DATA TYPE UUID USING (gen_random_uuid());

GRANT VIEW DEFINITION TO [user]; will allow the user to see the definitions of structures in the database, including tables, views, stored procedures, etc.

You'll need to do that for every database on the instance. There is no server-wide equivalent, out of the box, that limits permissions to just the database level.

If you need to limit it to just a single schema, then you'd do:

GRANT VIEW DEFINITION ON schema::[name_of_schema] TO [user];

https://dba.stackexchange.com/questions/128229/execute-system-commands-in-postgresql