oracle 自增长列

（1）建序列
-- Create sequence
create sequence WYZPID
minvalue 1
maxvalue 999999999999999999999999999
start with 21
increment by 1
cache 20;
（2）建触发器
CREATE OR REPLACE TRIGGER "WYZP_ID_TRIGGER"
BEFORE INSERT
ON TASKMANAGER.JYSC_WYYZ_WYZP
REFERENCING NEW AS NEW OLD AS OLD
FOR EACH ROW
DECLARE
newId INTEGER;
BEGIN
newId :=0;
SELECT WYZPID.nextval INTO newId FROM dual;
:new.id := newId;
END WYZP_ID_TRIGGER;