oracle 实现自增字段

oracle 中没有auto_increment属性，所以我们必须换一种方法实现。一般常用的方法为创建sequence，然后为对应表的创建trigger。如下：

--建表
CREATE TABLE CHIP01.DX_TEST
(
  ID        NUMBER                              NOT NULL,
  STU_ID    NUMBER                              NOT NULL,
  STU_NAME  VARCHAR2(200 BYTE)                  NOT NULL,
  STU_ADD   VARCHAR2(500 BYTE),
  STU_AGE   NUMBER(5)                           NOT NULL
);
--主键
ALTER TABLE CHIP01.DX_TEST ADD (
  CONSTRAINT P_ID
 PRIMARY KEY
 (ID)
);
--UNIQUE KEY
ALTER TABLE DX_TEST ADD CONSTRAINT U_STU_ID UNIQUE(STU_ID);

--创建sequence
CREATE OR REPLACE SEQUENCE AUTO_INCREMENT
     START WITH 1
     NOMAXVALUE
     MINVALUE 1
     NOCYCLE
     NOCACHE;

--创建trigger
CREATE OR REPLACE TRIGGER AUTOINCREMENT
BEFOR INSERT ON DX_TEST
REFERENCING NEW AS New OLD AS Old
BEGIN
       FOR EACH ROW
             SELECT AUTO_INCREMENT.NEXTVAL INTO :NEW.ID FROM DUAL;
END AUTOINCREMENT;