在Oracle中設置主鍵自增

轉自：https://www.2cto.com/database/201705/636725.html

數據庫設置主鍵自增">oracle數據庫設置主鍵自增：

--創建表
create table blog(
id integer primary key,
title varchar2(200),
content varchar2(20000),
user_id varchar2(45),
pub_date date);
 
--創建sequence：
create sequence blog_id_sequence
increment by 1
start with 1
nomaxvalue
nocache;
 
--創建觸發器：
create trigger blog_id_autoincrement before 
insert on blog for each row 
when (new.id is null)
begin
select blog_id_sequence.nextval into：new.id from dual;
end;