實現(xiàn)Oracle數(shù)據(jù)庫的逐漸自增
Jun 07, 2016 pm 04:55 PM1、 第一次NEXTVAL返回的是初始值;隨后的NEXTVAL會自動增加你定義的INCREMENT BY值,然后返回增加后的值。CURRVAL 總是返回當(dāng)前
將表t_uaer的字段ID設(shè)置為自增:(用序列sequence的方法來實現(xiàn))
----創(chuàng)建表
Create table t_user(
Id number(6),userid varchar2(20),loginpassword varchar2(20),isdisable number(6)
);
----創(chuàng)建序列
create sequence user_seq
increment by 1
start with 1
nomaxvalue
nominvalue
nocache
----創(chuàng)建觸發(fā)器
create or replace trigger tr_user
before insert on t_user
for each row
begin
select user_seq.nextval into :new.id from dual;
end;
----測試
insert into t_user(userid,loginpassword, isdisable)
values('ffll','liudddyujj', 0);
insert into t_user(userid,loginpassword, isdisable)
values('dddd','zhang', 0)
select * from t_user;
就可以看出結(jié)果。

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