第一步：为表设置主键

第二步：新建序列

CREATE SEQUENCE SQ.SEQ_INCREASE

  START WITH 12

  MAXVALUE 999

  MINVALUE 0

  INCREMENT BY 1

  NOCYCLE

  NOCACHE

  NOORDER;

第三步：创建触发器

CREATE OR REPLACE TRIGGER SQ.tg_depid_increase

BEFORE INSERT

ON SQ.SYS_DEPARTMENT //表名

REFERENCING NEW AS New OLD AS Old

FOR EACH ROW

WHEN (

New.id is null

      )

BEGIN

select seq_increase.nextval into :New.id from dual;

END tg_depid_increase;