虛擬屬性在保存時爲零通過accep_nested_attributes_for

Question

當我通過嵌套屬性保存記錄時，虛擬屬性不會在子模型中設置。

class Person < ActiveRecord::Base 
    has_many :houses 
    accepts_nested_attributes_for :houses 
end 

class House < ActiveRecord::Base 
    attr_accessor :house_name #virtual 
    before_save do 
    puts attributes # doesn't include house_name when saving through parent model 
    puts @house_name # nil when saving through parent model 
    end 

end 

person = Person.find(1) 
person.houses.count #=> 3 
person.houses.first.house_name = 'crazy house' 
person.save # house_name not in attributes 

house = person.houses.first 
house.house_name = 'moms house' 
house.save #house_name is in attributes 

Answer 1

您的代碼：

person.houses.first.house_name = 'crazy house' 

獲取的第一個關聯House。 Person無法知道你是否改變它的房子。我想，你只是高估了魔法。所有你需要的是房子的update_attributes：

person.houses.first.update_attributes house_name: 'crazy house'