OO和OB的区别

博客介绍了C++同时支持OO和OB两种设计。OO即面向对象,支持多态但有额外间接性;OB是非多态的数据封装模型,类似C中ADT概念,速度更快、空间更紧凑。指出OO和OB设计是在弹性和效率间的取舍。

C++同时支持OO和OB两种设计。

OOObject Oriented,支持多态这一强大的设计机制,需要付出的代价便是额外的间接性(virtual机制)。

OBObject Based,非多态的数据封装模型,就是C中ADT(Abstract Data Type)的概念,和OO相比拥有更快的速度而且空间更紧凑(因为不需要virtual)。

OO和OB的设计其实就是在弹性和效率之间的取舍。

-- 《Inside The C++ Object Model》

select * from ( select row_.*, rownum rownum_ from ( select * from ( select distinct OB.BUSI_ORDER_ID, 0 as HIS_ID, OB.BUSI_CODE, OB.CUST_ID, OB.CEASE_REASON, OB.ORDER_STATE, OB.CHANNEL_TYPE, ob.user_id, OB.IS_BATCH_ORDER, OB.APPLICATION_ID, OB.CREATE_DATE, OB.DONE_DATE, OB.EFF_DATE, OB.EXP_DATE, OB.OPER_ID, OB.ORG_ID, OB.REGION_ID, OB.NOTE, OB.PROCESS_STATE, nvl(oi.cust_name, ic.cust_name) cust_name, nvl(oc.icc_id, iu.icc_id) icc_id, nvl(oc.svc_num, iu.svc_num) svc_num, icp.cust_name parent_cust_name, icp.cust_id parent_cust_id, ol.order_list_id from ord_busi ob left join ord_offer oo on oo.busi_order_id = ob.busi_order_id and ob.user_id = oo.user_id left join info_user iu on oo.user_id = iu.user_id left join info_cust ic on ob.cust_id = ic.cust_id left join ord_cust oi on ob.cust_id = oi.cust_id and ob.busi_order_id = oi.busi_order_id left join info_cust icp on nvl(ic.parent_cust_id, oi.parent_cust_id) = icp.cust_id left join ( SELECT * FROM ord_user WHERE user_order_id IN ( SELECT MAX(user_order_id) user_order_id FROM ord_user GROUP BY busi_order_id,user_id ) ) oc on ob.user_id = oc.user_id and ob.busi_order_id = oc.busi_order_id left join ord_list ol on ob.busi_order_id = ol.busi_order_id WHERE 1 = 1 and OB.CUST_ID IN( SELECT DISTINCT CUST_ID FROM (SELECT CUST_ID, PARENT_CUST_ID FROM INFO_CUST UNION SELECT CUST_ID, PARENT_CUST_ID FROM ORD_CUST) TMP START WITH TMP.CUST_ID = '10001009208' CONNECT BY TMP.PARENT_CUST_ID = PRIOR TMP.CUST_ID ) union all select distinct OB.BUSI_ORDER_ID,OB.HIS_ID, OB.BUSI_CODE, OB.CUST_ID, OB.CEASE_REASON, OB.ORDER_STATE, OB.CHANNEL_TYPE, OB.USER_ID, OB.IS_BATCH_ORDER, OB.APPLICATION_ID, OB.CREATE_DATE, OB.DONE_DATE, OB.EFF_DATE, OB.EXP_DATE, OB.OPER_ID, OB.ORG_ID, OB.REGION_ID, OB.NOTE, OB.PROCESS_STATE, nvl(oi.cust_name,ic.cust_name) cust_name , nvl(oc.icc_id, iu.icc_id) icc_id, nvl(oc.svc_num,iu.svc_num) svc_num, icp.cust_name parent_cust_name, icp.cust_id parent_cust_id, ol.order_list_id from ord_busi_his ob left join ord_offer_his oo on oo.busi_order_id = ob.busi_order_id 优化一下
06-02
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