how to hide database objects from users, that don't have access to them

Hi,

Actually we've got a problem developing a DB with a lot of logic in it:
Our database has couple different interfaces to other systems (made
using views and procedures) and some interfaces need to be public or
semi-public. Even if we grant all rights correctly, each user, that able
to connect to the DB, has rights to view structures of all it components
(procedures/views/tables..) even he has no kind of access rights to them (!)

We've been little in trouble about, as far we can't open structure
and especial plenty a lot of logic inside in procedures (mainly written
in pgsql) to all users, as far we can't trust them.

If there any workaround to fix this and provide different users
interfaces to DB showing only objects, they have access to?

really would be grateful for help, as far we notice this hidden
trouble to late to change project design.

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Sincerely yours,
Oleksandr Pryymak