如何让Oracle表字段自动增长

转自：http://edu.codepub.com/2010/0821/25258.php

 

如何让Oracle表字段自动增长的学习例子：

1，订单表order1：

2, --创建订单表

create table order1(

order_id number(30) constraint pk_order_id primary key,

user_id number(30) not null,

pro_id number(30) not null,

p_amount number(10),

pay number(10),

c_number number(30),

pay_id number(5) not null,

state_id number(5) not null

);

--建立外键

alter table order1

add constraint order1_fk1 foreign key (pay_id)references pay(pay_id);

 

alter table order1

add constraint order1_fk2 foreign key (state_id) references state(state_id);

 

alter table order1

add constraint order1_fk3 foreign key (pro_id) references product(pro_id);

 

alter table order1

add constraint order1_fk4 foreign key (user_id) references use(user_id);

 

 

 

3，--自动生成订单序列

create sequence t_order_id_seq

increment by 1

start with 8100001

nomaxvalue

nocycle;

4,--创建触发器

create or replace trigger order_id_trigger

before insert

on order1

for each row

declare

newid number(18,0);

begin

select t_order_id_seq.nextval into newid from dual;

:new.order_id:=newid;

end;
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