-- create sequence 
create sequence innerid
minvalue 1
maxvalue 99999999999999
start with 1
increment by 1
cache 20
order;

insert into admin values (innerid.nextval,'a');
insert into admin values (innerid.nextval,'b');
insert into admin values (innerid.nextval,'c');
insert into admin values (innerid.nextval,'d');
create table admin
(id varchar2(20),name varchar2(10));

create or replace trigger admin_tg
--admin id 的触发器
before insert on admin for each row
begin
select innerid.nextval into :new.id from dual;
end;

insert into admin (username) values ( 'zdz');