1,创建sequence:
create sequence seq_sm_user
minvalue 1
maxvalue 999999999999999999999999999
start with 1
increment by 1
cache 20;
2,创建触发器:
create or replace trigger tg_sm_user
before insert on sm_user
referencing old as oldval
new as newval
for each row
begin
select seq_sm_user.nextval into :newval.pk_user from dual;
end;