Question

我在进行一些多对多关系的同时不断收到ActiveRecord :: AssociationTypeMismatch。

我尝试过更改模型的名称，即 has_many :subscribers, through: :rafflecontestants, source: :users 但这使我无处可去。

class Rafflecontestant < ApplicationRecord
  belongs_to :user
  belongs_to :raffle
end

class Raffle < ApplicationRecord
    validates :name, presence: true

    has_many :rafflecontestants
    has_many :users, through: :rafflecontestants
end

class User < ApplicationRecord
  # Include default devise modules. Others available are:
  # :confirmable, :lockable, :timeoutable, :trackable and :omniauthable
  devise :database_authenticatable, :registerable,
          :recoverable, :rememberable, :validatable

  has_many :rafflecontestants
  has_many :raffles, through: :rafflecontestants
end

和我的模式：

create_table "rafflecontestants", force: :cascade do |t|
    t.integer "user_id"
    t.integer "raffle_id"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.index ["raffle_id"], name: "index_rafflecontestants_on_raffle_id"
    t.index ["user_id"], name: "index_rafflecontestants_on_user_id"
  end

  create_table "raffles", force: :cascade do |t|
    t.string "name"
    t.text "description"
    t.integer "winner"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.integer "created_by"
  end

  create_table "users", force: :cascade do |t|
    t.string "email", default: "", null: false
    t.string "encrypted_password", default: "", null: false
    t.string "reset_password_token"
    t.datetime "reset_password_sent_at"
    t.datetime "remember_created_at"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.boolean "is_admin"
    t.string "authentication_token", limit: 30
    t.index ["authentication_token"], name: "index_users_on_authentication_token", unique: true
    t.index ["email"], name: "index_users_on_email", unique: true
    t.index ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true
  end

在控制台中复制的步骤：

u = User.create(...) 
r= Raffle.create(..., Rafflecontestants: [u])
ActiveRecord::AssociationTypeMismatch: Rafflecontestant(#66411640) expected, got #<User id: 1, email: "name@pnimedia.com", created_at: "2019-07-11 19:54:55", updated_at: "2019-07-11 19:54:55", is_admin: false, authentication_token: "yeU3mgQQPyXqDrMBFPAY"> which is an instance of User(#73796060)

我希望使用Rafflecontestants表将用户添加到抽奖活动中。

Answer 1

您不太正确地采用这种方式。

这两个都应该起作用，有关更多信息，请访问the guides

user = User.create(...)
raffle = Raffle.create(...)
raffle.users << user

或...

user = User.create(...)
raffle = Raffle.create(...)
user.raffles << raffle

如果联接模型Rafflecontestant上具有额外的属性，则必须这样做

user = User.create(...)
raffle = Raffle.create(...)
Rafflecontestant.create(user: user, raffle: raffle, some_extra_attribute: 1)

Answer 2

ApplicationRecord是否从ActiveRecord :: Base继承？

我使用ActiveRecord::Base进行了尝试，并且对我有用

user = User.create!
user.raffles.create!(name: "new raffle")
raffle = Raffle.last
user.rafflecontestants
# [#<Rafflecontestant:0x00007fda70313948 id: 1, user_id: 1, raffle_id: 1>]

如何通过关系修复has_many上的ActiveRecord :: AssociationTypeMismatch

2 个答案: