Rails-如何将一个“商店”与多个“购物中心”同时关联？

Question

I am making a simple rails app which acts as a directory of all Malls in Kuwait and Shops within that mall. I created a Shop model and Mall model and made the following association:-

class Shop
has_many_and_belongs_to :malls

class Mall
has_many :shops

As the same shop can exist in more than one mall, I would like a way for me to link a shop with more than one mall at the same time. How can I make it so that a shop automatically appears under many different malls when I go to that malls show page, without having to individually create the same shop each time for each mall. So in other words I need to be able to choose which malls the shop belongs to while im creating a new shop, and then have that shop appear in the malls that I previously specified.

Update: Explain assigning the shop to a particular mall in the creation process. For example when I create a new shop, how do I then specify that it belongs to Mall A and Mall B but not Mall C, and then have them appear in the corresponding Malls show page?

Answer 1

You can have a HABTM association to handle this,

   class Shop < ActiveRecord::Base
     has_and_belongs_to_many :malls
   end

   class Mall < ActiveRecord::Base
     has_and_belongs_to_many :shops
   end

Create migrations for Shop and Mall table, you need to have a migration to create a table which works as a join between shop and mall. It should contain mall_id and shop_id as attributes.

rails g migration create_mall_shops

Update for controller code:

 shop = Shop.find(params[:id])
 mall = Mall.find(params[:mall_id])
 shop.malls << mall

shop.malls will give you an array of malls related to shop. Now, coming back as you expect, in shop.malls array, push only mall object A and B. So mall C will never be related to shop