Is it possible, with PostgreSQL 9.0, to restrict access to specific table rows by `id`? I want a user to be able to INSERT new rows but not UPDATE or DELETE rows with `id` < 1616.
I believe that first you need to restrict SELECT. You can do it by creating view: CREATE VIEW myview AS SELECT ... FROM mytable ... WHERE id < 1616;
Next, you need define rules on UPDATE and DELETE to the view, e.g: CREATE RULE myview_rule_upd AS ON UPDATE TO myview DO INSTEAD UPDATE mytable SET (column1, column2, ...) = (NEW.column1, NEW.column2, ... );
CREATE RULE myview_rule_ins AS ON DELETE TO myview ...
For details please see "The rule system" chapter of documentation.