postgresql使现有主键在插入时自动递增

qid 这就是PK, question geo_type user_input active

所以我需要能够做到这一点

insert into sip_questions (question,geo_type,user_input,active) values('noury','octagon',TRUE,TRUE)

但这给了我这个错误

ERROR:  duplicate key value violates unique constraint "s_questions_pkey"
DETAIL:  Key (qid)=(1) already exists.

********** Error **********

ERROR: duplicate key value violates unique constraint "s_questions_pkey"
SQL state: 23505
Detail: Key (qid)=(1) already exists.

这是桌子

CREATE TABLE public.sip_questions
(
  qid integer NOT NULL DEFAULT nextval('s_questions_qid_seq'::regclass),
  question character varying(200),
  geo_type character varying(10),
  user_input boolean,
  active boolean,
  CONSTRAINT s_questions_pkey PRIMARY KEY (qid)
)
WITH (
  OIDS=FALSE
);
ALTER TABLE public.sip_questions
  OWNER TO postgres;

我知道如何在这样一张新鲜的桌子上做这件事

ALTER TABLE table ADD COLUMN id SERIAL PRIMARY KEY;