用代码来实现oracle自动增加1功能

用代码来实现oracle自动增加1功能
创建序列:-- Create sequence
create sequence IP_Test_SEQUENCES
minvalue 1
maxvalue 99999999999999999999999999
start with 1
increment by 1
cache 20
order;
创建触发器：
create or replace trigger IP_Test_Trigger
  before insert on ip_test
  for each row
declare
  -- local variables here
  next_id number;
begin
 select IP_Test_Sequences.nextval into next_id from dual;
 :new.id:=next_id;
 --select IP_Test_Sequences.nextval into :new.id from dual;
end IP_Test_Trigger;