轨道在多对多关系中单位化常数误差

Question

我正在尝试创建一种关系，在该关系中，用户可以拥有许多订单和许多产品，订单可以有许多产品但属于一个用户，并且产品可以有许多用户和许多订单。

到目前为止，我有下面的代码，其中包含上述三个模型以及一个连接表。我遇到的问题是，例如，每当我尝试访问user.products时，我都会收到uninitialized constant Order::ProductOrder错误，或者如果我尝试product.orders，我就会uninitialized constant Product::Orders。

有人会好心地为解决这个问题提供他们的经验吗？

class Order < ApplicationRecord
belongs_to :user
has_many :product_orders
has_many :products, through: :product_orders
end

---

class Product < ApplicationRecord
has_many :product_orders, class_name: 'ProductOrders'
has_many :orders, through: :product_orders
has_many :users, through: :orders
end

---

class User < ApplicationRecord
has_many :orders
has_many :products, through: :orders
end

---

class ProductOrders < ApplicationRecord
belongs_to :orders
belongs_to :products
end

数据库架构：

create_table "orders", force: :cascade do |t|
t.datetime "fulfilled_date"
t.integer "quantity"
t.integer "total"
t.bigint "user_id"
t.index ["user_id"], name: "index_orders_on_user_id"
end
create_table "product_orders", force: :cascade do |t|
t.bigint "product_id"
t.bigint "order_id"
t.index ["order_id"], name: "index_product_orders_on_order_id"
t.index ["product_id"], name: "index_product_orders_on_product_id"
end
create_table "products", force: :cascade do |t|
t.string "image_url"
t.string "name"
t.string "description"
t.integer "inventory", default: 0
t.integer "price"
t.bigint "order_id"
t.bigint "user_id"
t.index ["order_id"], name: "index_products_on_order_id"
t.index ["user_id"], name: "index_products_on_user_id"
end
create_table "users", force: :cascade do |t|
t.string "name"
t.string "email"
t.string "address"
t.string "state"
t.string "zip"
t.string "phone_number"
t.string "country"
end

Answer 1

需要更正几处：

在Order中添加:product_ordersclass_name;

class Order < ApplicationRecord
belongs_to :user
has_many :product_orders, class_name: 'ProductOrders'
has_many :products, through: :product_orders
end

belongs_to应该有单数order和product：

class ProductOrders < ApplicationRecord
belongs_to :order
belongs_to :product
end