讲解Oracle数据库自动增长列的实现过程

-- 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'');