Oracle实现字段自动增长

序列：
CREATE SEQUENCE "user"."sequence_name" INCREMENT BY 1 START WITH 1
MAXvalue 1.0E28 MINvalue 1 NOCYCLE
CACHE 20 NOORDER;

触发器：
CREATE OR REPLACE TRIGGER "user"."trigger_name" BEFORE
INSERT ON "user"."table" FOR EACH ROW begin
Select "user"."sequence_name".Nextval into :New.ID From Dual;
end;