关联设置正确导致未初始化的常量

Question

我在 User 和 Stake 之间有一个简单的 many_to_many 关系到 UserStake，一切似乎都设置正确但结果是 NameError (uninitialized constant User::Stakes)：

#db/schema.rb
ActiveRecord::Schema.define(version: 2020_12_19_070749) do

  create_table "stakes", force: :cascade do |t|
    t.string "address"
    t.datetime "created_at", precision: 6, null: false
    t.datetime "updated_at", precision: 6, null: false
  end

  create_table "user_stakes", force: :cascade do |t|
    t.integer "user_id"
    t.integer "stake_id"
    t.datetime "created_at", precision: 6, null: false
    t.datetime "updated_at", precision: 6, null: false
  end

  create_table "users", force: :cascade do |t|
    t.string "username"
    t.datetime "created_at", precision: 6, null: false
    t.datetime "updated_at", precision: 6, null: false
    t.string "password_digest"
  end

end

#app/models/stake.rb
class Stake < ApplicationRecord
    has_many :active_stakes
    has_many :user_stakes
    has_many :users, through: :user_stakes
end

#app/models/user.rb
class User < ApplicationRecord
    has_many :user_stakes
    has_many :stakes, through: :user_stakes
    
    has_secure_password
end

#app/models/user_stake.rb
class UserStake < ApplicationRecord
    belongs_to :users
    belongs_to :stakes
end

当我尝试通过 rails c 进行关联时，出现以下错误 NameError (uninitialized constant User::Stakes)：

2.6.3 :019 > s
 => #<Stake id: 310524, address: "stake1u8003gtvhcunzzmy85nfnk6kafd8lks2mykfzf0n4hq4...", created_at: "2020-12-08 12:08:25", updated_at: "2020-12-08 12:08:25"> 
2.6.3 :020 > u
 => #<User id: 21, username: "s324xexd", created_at: "2020-12-19 00:16:31", updated_at: "2020-12-19 00:16:31", password_digest: [FILTERED]> 
2.6.3 :021 > u.stakes << s
Traceback (most recent call last):
        1: from (irb):21
NameError (uninitialized constant User::Stakes)
2.6.3 :022 > u.stakes
Traceback (most recent call last):
        2: from (irb):22
        1: from (irb):22:in `rescue in irb_binding'
NameError (uninitialized constant User::Stakes)

Answer 1

belongs_to 协会必须使用单数术语。

#app/models/user_stake.rb
class UserStake < ApplicationRecord
    belongs_to :user
    belongs_to :stake
end

The belongs_to Association

belongs_to associations must use the singular term. If you used the pluralized form in the above example for the author association in the Book model and tried to create the instance by Book.create(authors: @author), you would be told that there was an "uninitialized constant Book::Authors". This is because Rails automatically infers the class name from the association name. If the association name is wrongly pluralized, then the inferred class will be wrongly pluralized too.

关联设置正确导致未初始化的常量

Associations Setup Correctly Results in a Uninitialized Constant

ruby

many-to-many

ruby-on-rails

associations