How to auto-increment in PostgreSQL? [duplicate]

Answer 1

A Sequence can be created which will auto increment the value of rank column.

CREATE SEQUENCE rank_id_seq;

CREATE TABLE yourtable (
    rank INTEGER NOT NULL default nextval('rank_id_seq'),
    username VARCHAR(20) NOT NULL,
    password VARCHAR(50) NOT NULL
);

ALTER SEQUENCE rank_id_seq owned by yourtable.rank;