An artificial key is an attribute that is supposed to be unique and increase each time you add a row/record. In Postgres, it's called sequences. The type of the attribute is SERIAL.
-- start with 1 and will increment by 1 ... CREATE SEQUENCE public.sequence_name START WITH 1 INCREMENT BY 1 NO MINVALUE NO MAXVALUE CACHE 1; -- set sequence for attribute "a_column_name" -- replace a_table_name and a_column_name ALTER TABLE ONLY public.a_table_name ALTER COLUMN a_column_name -- replace sequence_name SET DEFAULT nextval('public.sequence_name'::regclass);