oracle触发器和自动增长列

//创建addmanage表create table addmanage(aid varchar2(10) primary key,managename varchar2(30),managepass varchar2(100))//创建自动增长段create sequence addmanage_sequencestart with 1increment by 1nomaxvaluecache 20//创建触发器create or replace trigger addmanage_triggerbefore inserton addmanage<!--addmanage创建的表名-->for each rowwhen(new.aid is null)<!--aid表的主键-->beginselect addmanage_sequence.nextval into:new.aid from dual;end;