oracle学习------实现某列自增长

建表:

SQL> create table MEDIA_INFO (
  2 meida_id number(10) not null,
  3 dept_id number(5) not null,
  ...
 11 constraint PK_ISO_DOC_INFO primary key(ID),
 ...
 14 ;


建sequence:

CREATE SEQUENCE MEDIA_INFO_SEQUENCE
          INCREMENT BY 1 -- 每次加几个
          START WITH 1 -- 从1开始计数
          NOMAXVALUE -- 不设置最大值
          NOCYCLE -- 一直累加，不循环
          NOCACHE -- 不建缓冲区


创建触发器:

CREATE OR REPLACE TRIGGER MEDIA_INFO_TR
BEFORE INSERT ON MEDIA_INFO FOR EACH ROW
begin
Select MEDIA_INFO_SEQUENCE.NEXTVAL
Into :new.MEDIA_ID
from dual;
end;
/