軌道4的has_many：通過級聯的複選框值

Question

基於刪除我有一個的has_many：通過關聯如下

Customer-> 
has_many :customer_materials, :dependent => :destroy 
has_many :materials, :through => :customer_materials 

CustomerMaterial -> #This is the lookout table for a price attribute 
belongs_to :customer 
belongs_to :material 

Material -> 
has_many :customer_materials, :dependent => :destroy 
has_many :customers, :through => :customer_materials 

並非所有的客戶通過查找表有這樣的自訂價格。只有當客戶的custom_price布爾值被選中時，我才使用查找表。如果custom_price布爾值爲false，則使用Material表中由price屬性跟蹤的默認價格。

當我編輯客戶並取消選中custom_price複選框時，我想繼續並在查找表上觸發級聯刪除。這是我更新的控制器方法。如何修改方法以基於custom_price屬性進行條件更新？

def update 
    @customer = Customer.find(params[:id]) 
    if @customer.update_attributes(customer_params) 
    flash[:success] = "Record Updated Successfully" 
    redirect_to customers_url 
    else 
    flash.now[:error] = @customer.errors.full_messages.to_sentence 
    render 'edit' 
    end 
end 

Answer 1

class Customer < ActiveRecord::Base 
    after_save :delete_custom_prices, :unless => Proc.new {|model| model.custom_price? } 

    def delete_custom_prices 
    customer_materials.delete_all 
    end 
end