触发器例子

如果设备表中的设备状态发生了改变，那么向消息表中插入数据

create OR REPLACE trigger trigger_XX after update on T_XX for each row begin if updateing then    when(:new.DEVICE_STATUS<>:old.DEVICE_STATUS )    begin        select SEQ_XX_NEWS.NEXTVAL as ids    insert into T_XX_REPORT_NEWS (id,REPORTNEWS) values(ids,:new.DEVICE_ID );    end end if; end;

create OR REPLACE trigger trigger_XX after update on T_XX for each row begin if(:new.DEVICE_STATUS<>:old.DEVICE_STATUS) then    insert into T_XX_REPORT_NEWS (id,REPORTNEWS,Reporttime) values(SEQ_XX_REPORT_NEWS.NEXTVAL,:new.DEVICE_ID,TO_CHAR(sysdate, 'yyyy-MM-dd HH24:MI:ss') ); end if; end;