create table t_news
(
newsid number not null primary key, //自增字段
title varchar2(50)
)
create sequence seq_news
minvalue = 1
maxvalue = 99999999
increment by 1;
create or replace trigger t_tri_news
before insert on t_news
for each row
select seq_news.nextval into :new.newsid from dual;
end;
insert into t_news ( newsid , title)
values( seq_news.nextval ,'aaa');
commit;
