DB2 does not authorize by schema, only by table, or the entire database for certain athorities like DBADM. You can find the table authorities in SYSCAT.TABAUTH catalog view. Database level authorities are in SYSCAT.DBAUTH. To find the list of all tables, independent of authorizations granted, you would look in SYSCAT.TABLES (but check the table "type" since it includes other objects such as views, etc).