mysql - Rails 多个 has_many 通过不同的模型到单个模型

Question

我是 rails 的新手，我需要一些帮助来构建 rails 模型。 我有四个模型 User、Product、UserSavedProduct、likedProduct。

用户可以通过usersavedproducts和liked products拥有很多产品，这些是我的模型。这是写它们的正确方法吗？如果是这样如何获得所有保存的产品，单个用户喜欢的产品，否则你能给我指明正确的方向吗。

class User < ActiveRecord::Base

  has_many :user_saved_products

  has_many :saved_products,:through => :user_saved_products,:source => :products

  has_many :product_likes

  has_many :products,:through => :product_likes

End


class UserSavedProduct < ActiveRecord::Base

  belongs_to :user

  belongs_to :product

end

class ProductLike < ActiveRecord::Base

  belongs_to :user

  belongs_to :product

end


class Product < ActiveRecord::Base

  belongs_to :user

  has_many :user_saved_products

  has_many :users, :through => :user_saved_products

  has_many :product_likes

  has_many :users,:through => :product_likes

end

当我执行 User.first.methods.grep(/product/) 时

=> [:autosave_associated_records_for_user_saved_products, :validate_associated_records_for_user_saved_products, :before_add_for_user_saved_products, :before_add_for_user_saved_products?, :before_add_for_user_saved_products=, :after_add_for_user_saved_products, :after_add_for_user_saved_products?, :after_add_for_user_saved_products=, :before_remove_for_user_saved_products, :before_remove_for_user_saved_products?, :before_remove_for_user_saved_products=, :after_remove_for_user_saved_products, :after_remove_for_user_saved_products ?, :after_remove_for_user_saved_products=, :autosave_associated_records_for_saved_products, :validate_associated_records_for_saved_products, :before_add_for_saved_products, :before_add_for_saved_products?, :before_add_for_saved_products=, :after_add_for_saved_products, :after_add_for_saved_products?, :after_add_for_saved_products=, :before_remove_for_saved_products, :before_remove_for_saved_products?, :before_remove_for_saved_products=, :after_remove_for_saved _products, :after_remove_for_saved_products?, :after_remove_for_saved_products=, :autosave_associated_records_for_product_likes, :validate_associated_records_for_product_likes, :before_add_for_product_likes, :before_add_for_product_likes?, :before_add_for_product_likes=, :after_add_for_product_likes, :after_add_for_product_likes?, :after_add_for_product_likes=, :before_remove_for_product_likes, :before_remove_for_product_likes?, :before_remove_for_product_likes=, : after_remove_for_product_likes, :after_remove_for_product_likes?, :after_remove_for_product_likes=, :autosave_associated_records_for_liked_products, :validate_associated_records_for_liked_products, :before_add_for_liked_products, :before_add_for_liked_products?, :before_add_for_liked_products=, :after_add_for_liked_products, :after_add_for_liked_products?, :after_add_for_liked_products=, :before_remove_for_liked_products, :before_remove_for_liked_products?, :before_remove_for_liked_products=, : after_remove_for_liked_products， :after_remove_for_liked_products?, :after_remove_for_liked_products=, :user_saved_products, :user_saved_product_ids, :user_saved_products=, :user_saved_product_ids=, :saved_products, :saved_product_ids, :saved_products=, :saved_product_ids=, :product_likes, :product_like_ids, :product_likes=, :product_like_ids=, :liked_products, :liked_product_ids, :liked_products=, :liked_product_ids=]

Answer 1

您遇到的主要问题是您的 Product 模型 - 您有多个 :users 关联。我会这样设置。

我必须从产品中选择两个关联名称返回给用户。我选择了liking_users和saving_users，如果不喜欢可以重命名。

如果我这样做，我会将 ProductLike 类重命名为“UserLikedProduct”，使其与“UserSavedProduct”一致。显然，如果您这样做，您将需要更改数据库表名和引用该表​​的关联。

class User < ActiveRecord::Base
  has_many :user_saved_products
  has_many :saved_products, :through => :user_saved_products, :class_name => "Product"
  has_many :product_likes
  has_many :liked_products,:through => :product_likes, :class_name => "Product"
end

class Product < ActiveRecord::Base
  has_many :user_saved_products
  has_many :saving_users, :through => :user_saved_products, :class_name => "User"
  has_many :product_likes
  has_many :liking_users, :through => :product_likes, :class_name => "User"
end    

class UserSavedProduct < ActiveRecord::Base
  belongs_to :user
  belongs_to :product
end

class ProductLike < ActiveRecord::Base
  belongs_to :user
  belongs_to :product
end