oracle创建id自增

CREATE TABLE STUDENT
(
ID INT NOT NULL,
NAME VARCHAR2(4000) NOT NULL,
PRIMARY KEY(ID)
)
TABLESPACE MYDB;
 
--创建自增ID，名称为：表名_字段名_SEQ
CREATE SEQUENCE sTUDENT_ID_SEQ MINVALUE 1 NOMAXVALUE INCREMENT BY 1 START WITH 1 NOCACHE;
 
 
-- 为Insert操作创建触发器，无需在SQL语句里写NEXTVAL，名称为表名_INS_TRG
CREATE OR REPLACE TRIGGER sTUDENT_INS_TRG BEFORE INSERT ON STUDENT FOR EACH ROW WHEN(NEW.ID IS NULL)
BEGIN
SELECT STUDENT_ID_SEQ.NEXTVAL INTO :NEW.ID FROM DUAL;
END;