rails has_many:通过has_many:through

Question

我想知道我可以在多大程度上使用Rails中的关联.考虑以下因素:

class User < ActiveRecord::Base
    has_one :provider
    has_many :businesses, :through => :provider
end

class Provider < ActiveRecord::Base
    has_many :businesses
    has_many :bids, :through => :businesses
    belongs_to :user
end

class Business < ActiveRecord::Base
    has_many :bids
    belongs_to :provider
end

class Bid < ActiveRecord::Base
    belongs_to :business
end

我可以设置这些漂亮的快捷方式User.businesses,Provider.bids但是做些什么User.bids呢？是否可以关联一个协会,可以这么说？

Answer 1

这是完全可能的,但需要一些额外的工作.以下模型定义与nested_has_many插件结合使用,您只需获取属于用户的所有出价@user.bids

class User < ActiveRecord::Base
    has_one :provider
    has_many :businesses, :through => :provider
    has_many :bids, :through => :businesses
end

class Provider < ActiveRecord::Base
    has_many :businesses
    has_many :bids, :through => :businesses
    belongs_to :user
end

class Business < ActiveRecord::Base
    has_many :bids
    belongs_to :provider
end

class Bid < ActiveRecord::Base
    belongs_to :business
end

但是,从出价中获取用户将需要更多工作.