there are one hundred million defferent manufacturer, all have "A4", "A8", "A12", "A16"... model car. manufacturer and model is many-to-many relationship. Particularly large data. struct _Modify_price { _Modify_price(int price_):m_price_(price_){} void operator()(car_model& cm_) { cm_.price = m_price_; } private: int m_price_; }; ------------------ 原始邮件 ------------------ 发件人: "Joaquin M Lopez Munoz"; 发送时间: 2010年7月26日(星期一) 凌晨2:49 收件人: "boost-users"; 主题: Re: [Boost-users] Multi_indexcomposite_key isjk writes:

Oh, sorry.

Nothing to be sorry about. On another topic, please don't top-post and try to follow the discussion policies of the list as summarized at http://www.boost.org/community/policy.html

Assume "cadillac" have "A4" model, "bmw" have "A4" model too. now, if I will querying "A4" 's price, I must kown the manufacturer.

ordered_no_unique< tag<model>,BOOST_MULTI_INDEX_MEMBER(car_model,std::string,model),

Correct, you must change from the example's original ordered_unique to ordered_no_unique so as to allow cars with from different manufacturers yet the same model name.

ct.insert(car_model("A4",cadillac,78901)); ct.insert(car_model("A4",bmw,65412));

index_iterator::type im0,im1; boost::tuples::tie(im0,im1)=get<model>(ct).equal_range(model);

car_table_manufacturer_view ctmv; copy(im0,im1,back_inserter(ctmv)); car_table_manufacturer_view::iterator ictmv = ctmv.find(cm);

This looks right (haven't compiled it), although a little contrived: unless you expect to have *many* cars with the same model name, you can just traverse [im0,im1) and locate the car you're after.

ctmv.modify(cctmv, _Modify_price(10000)); // right or wrong???

I don't know how you've defined _Modify_price. Care to show? Joaquín M López Muoz Telefónica, Investigación y Desarrollo _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users