转自(https://blog.csdn.net/zxh2075/article/details/78488141)
create table dectuser(
userid integer primary key, /*主键*/
name varchar2(20),
sex varchar2(2)
);
select *from dectuser
drop sequence dectuser_tb_seq;
create sequence dectuser_tb_seq minvalue 1 maxvalue 99999999
increment by 1
start with 1;
create or replace trigger dectuser_tb_tri
before insert on dectuser /*触发条件:当向表dectuser执行插入操作时触发此触发器*/
for each row /*对每一行都检测是否触发*/
begin /*触发器开始*/
select dectuser_tb_seq.nextval into :new.userid from dual;
/*触发器主题内容,即触发后执行的动作,在此是取得序列dectuser_tb_seq的下一个值插入到表dectuser中的userid字段中*/
end;
insert into dectuser(name,sex) values ('feng','男')
commit; /*提交*/