Question

我正在努力建立has_many：通过卖方和买方之间的关系来产品。

product.rb

class Product < ActiveRecord::Base
  resourcify
  include Authority::Abilities
  self.authorizer_name = 'ProductAuthorizer'

  belongs_to :seller, :class_name => 'User', :foreign_key => 'seller_id', required: false

  has_many :purchasements
  has_many :buyers, :class_name => 'User', through: :purchasements

  has_many :comments, as: :commentable, dependent: :destroy
end

purchasement.rb

class Purchasement < ApplicationRecord
  belongs_to :buyer
  belongs_to :purchase
end

user.rb

class User < ActiveRecord::Base
  devise :database_authenticatable, :registerable,
     :recoverable, :rememberable, :trackable, :validatable
  rolify
  include Authority::UserAbilities

  has_many :sales, :class_name => 'Product', :foreign_key => 'sale_id'

  has_many :purchasements
  has_many :purchases, :class_name => 'Product', through: :purchasements
end

产品迁移

class CreateProducts < ActiveRecord::Migration
  def change
    create_table :products do |t|
      t.string :title
      t.text :content
      t.integer :price

      t.belongs_to :seller, index: true

      t.integer :purchase_count, default: 0, null: false

      t.timestamps null: false
    end
  end
end

购买迁移

class CreatePurchasements < ActiveRecord::Migration[5.0]
  def change
    create_table :purchasements do |t|
      t.belongs_to :buyer, index: true #상품 입장에서의 구매자들
      t.belongs_to :purchase, index: true #구매자 입장에서의 상품들

      t.timestamps
    end
  end
end

products_controller.rb

def create
  @product = Product.new(product_params)
  @product.seller = current_user
  authorize_action_for @product
  #remote true 가 적용된 폼에는 token 이 포함되지 않는다. 따로 포함하라고 말해줘야함.

  if @product.save
    redirect_to @product, notice: '상품 업로드 완료'
  else
    Rails.logger.info(@product.errors.inspect)
    flash[:error] = 'fjeislafsa'
    render :new
  end
end

def download
  if points_check(@product)
    @product.purchase_count += 1
    @product.buyers << current_user
    #current_user.purchases << @product
    @product.save
    redirect_to @product.file.expiring_url(10)
  else
    redirect_to payments_path
  end
end

问题是当用户尝试下载（购买）产品时。

@ product.buyers不起作用并给出此错误'NameError：uninitialized constant Purchasement :: Buyer “

我的目标是让产品只有一个卖家（用户），并拥有多个买家（用户）。另一方面，用户可以同时拥有许多销售（产品）和购买（产品）。

我在某处感到困惑，无法找到修复的地方。

非常感谢。

额外错误

Started GET "/products/download/1" for 127.0.0.1 at 2017-03-26 18:22:10 +0900
Processing by Shop::ProductsController#download as HTML
  Parameters: {"id"=>"1"}
  User Load (0.3ms)  SELECT  "users".* FROM "users" WHERE "users"."id" = $1 ORDER BY "users"."id" ASC LIMIT $2  [["id", 1], ["LIMIT", 1]]
  Product Load (0.1ms)  SELECT  "products".* FROM "products" WHERE        "products"."id" = $1 LIMIT $2  [["id", 1], ["LIMIT", 1]]
   (0.1ms)  BEGIN
  SQL (0.2ms)  UPDATE "users" SET "point" = $1, "updated_at" = $2 WHERE "users"."id" = $3  [["point", 9948], ["updated_at", 2017-03-26 09:22:10 UTC], ["id", 1]]
   (1.1ms)  COMMIT
   (0.1ms)  BEGIN
   (0.1ms)  ROLLBACK
Completed 500 Internal Server Error in 64ms (ActiveRecord: 8.9ms)



ActiveModel::UnknownAttributeError (unknown attribute 'product_id' for Purchasement.):

app/controllers/shop/products_controller.rb:67:in `download'
  Rendering /Users/mac/.rvm/gems/ruby-2.3.0/gems/actionpack-5.0.1/lib/action_dispatch/middleware/templates/rescues/diagnostics.html.erb within rescues/layout
  Rendering /Users/mac/.rvm/gems/ruby-2.3.0/gems/actionpack-5.0.1/lib/action_dispatch/middleware/templates/rescues/_source.html.erb
  Rendered /Users/mac/.rvm/gems/ruby-2.3.0/gems/actionpack-5.0.1/lib/action_dispatch/middleware/templates/rescues/_source.html.erb (3.9ms)
  Rendering /Users/mac/.rvm/gems/ruby-2.3.0/gems/actionpack-5.0.1/lib/action_dispatch/middleware/templates/rescues/_trace.html.erb
  Rendered /Users/mac/.rvm/gems/ruby-2.3.0/gems/actionpack-5.0.1/lib/action_dispatch/middleware/templates/rescues/_trace.html.erb (1.9ms)
  Rendering /Users/mac/.rvm/gems/ruby-2.3.0/gems/actionpack-5.0.1/lib/action_dispatch/middleware/templates/rescues/_request_and_response.html.erb
  Rendered /Users/mac/.rvm/gems/ruby-2.3.0/gems/actionpack-5.0.1/lib/action_dispatch/middleware/templates/rescues/_request_and_response.html.erb (0.9ms)
  Rendered /Users/mac/.rvm/gems/ruby-2.3.0/gems/actionpack-5.0.1/lib/action_dispatch/middleware/templates/rescues/diagnostics.html.erb within rescues/layout (53.5ms)

Answer 1

class Purchasement < ApplicationRecord
  belongs_to :buyer
  belongs_to :purchase
end

鉴于上述声明，Rails尝试将买方协会与买方类关联，并与Purchase类购买关联，两者都不存在。

您还应在此处指定模型类名称：

class Purchasement < ApplicationRecord
  belongs_to :buyer, class_name: 'User'
  belongs_to :purchase, class_name: 'Product'
end

Rails，在卖家和买家之间有很多关系

1 个答案: