ORACLE中设置ID自增详细

create table t_user(
user_id number not null primary key,
user_name varchar2(30),
credits number,
user_password varchar2(32),
last_visit date,
last_ip varchar2(23)
)

create sequence T_USER_SEQ
minvalue 1
maxvalue 999999999999999999999999999
start with 21
increment by 1
cache 20;


create or replace trigger t_user_tr
before insert on t_user
for each row
begin
select t_user_seq.nextval into :new.user_id from dual;
end t_user_tr;


insert into t_user values(null,'xiaoming',123,'1114',sysdate,'192.168.37.132');
insert into t_user values(null,'xiaoming1',123,'1114',sysdate,'192.168.37.132');
insert into t_user values(null,'xiaoming1',123,'1114',sysdate,'192.168.37.132');
insert into t_user values(null,'xiaoming1',123,'1114',sysdate,'192.168.37.132');
insert into t_user values(null,'xiaoming2',123,'1114',sysdate,'192.168.37.132');
insert into t_user values(null,'xiaoming',123,'1114',sysdate,'192.168.37.132');
insert into t_user values(null,'xiaoming',123,'1114',sysdate,'192.168.37.132');
insert into t_user values(null,'xiaoming',123,'1114',sysdate,'192.168.37.132');
insert into t_user values(null,'xiaoming',123,'1114',sysdate,'192.168.37.132');
insert into t_user values(null,'xiaoming',123,'1114',sysdate,'192.168.37.132');


select * from t_user

第一步：
创建一张表

create table t_user(
user_id number not null primary key,
user_name varchar2(30),
credits number,
user_password varchar2(32),
last_visit date,
last_ip varchar2(23)
)

2. 为这个表创建序列

 create sequence T_USER_SEQ
minvalue 1 
maxvalue 999999999999999999999999999      -- 最大值 
start with 21           -- 从21开始 
increment by 1     -- 每次递增1 
cache 20;            --制定存入缓存（也就是内存）序列值的个数 默认20

3. 创建一个触发器
   t_user_tr:随意的名字，不要重复就行
   t_user:表名
   user_id ：自增的id

create or replace trigger t_user_tr
before insert on t_user
for each row
begin
select t_user_seq.nextval into :new.user_id from dual;
end t_user_tr;

4. 测试

insert into t_user values(null,'xiaoming',123,'1114',sysdate,'192.168.37.132');
insert into t_user values(null,'xiaoming1',123,'1114',sysdate,'192.168.37.132');
insert into t_user values(null,'xiaoming1',123,'1114',sysdate,'192.168.37.132');
insert into t_user values(null,'xiaoming1',123,'1114',sysdate,'192.168.37.132');
insert into t_user values(null,'xiaoming2',123,'1114',sysdate,'192.168.37.132');
insert into t_user values(null,'xiaoming',123,'1114',sysdate,'192.168.37.132');
insert into t_user values(null,'xiaoming',123,'1114',sysdate,'192.168.37.132');
insert into t_user values(null,'xiaoming',123,'1114',sysdate,'192.168.37.132');
insert into t_user values(null,'xiaoming',123,'1114',sysdate,'192.168.37.132');
insert into t_user values(null,'xiaoming',123,'1114',sysdate,'192.168.37.132');

5.查看结果

select * from t_user

这样就可以 本人亲试过；
oralce的自增id