Question

使用Rails 5，当我尝试保存这两个模型之间的关联时，我遇到了一个问题：用户和提供商

我的模特：

class User < ApplicationRecord
   # Relations
   has_and_belongs_to_many :providers
end


class Provider < ApplicationRecord
  # Relations
  has_and_belongs_to_many :users
  accepts_nested_attributes_for :users
end

控制器：

class ProvidersController < ApplicationController
  def new
    @provider = current_user.providers.new
  end

  def create
    @provider = current_user.providers.new(provider_params)
    if @provider.save
      redirect_to root_path
    else
      render :new
    end
  end

  private

    def provider_params
      params[:provider][:status] = 'name'
      params.require(:provider).permit(:name, :status)
    end

表格：

= simple_form_for @provider do |f|
  = f.error_notification
  = f.input :name, required: false
  = f.button :submit

在创建操作上，创建了一个新提供程序，但它未链接到当前用户。（连接表中没有数据插入）

我不知道为什么会有这种行为。在控制台中，如果我做了类似的事情：

@user = User.create(email: "user@test.com", password: "password")
@provider = @user.providers.create(name: "Provider1", status: "name")
@provider.save

然后正确保存关联。

 > @user.providers
 => #<ActiveRecord::Associations::CollectionProxy [#<Provider id: 17, name: "Provider1", status: "name", created_at: "2017-07-25 09:37:19", updated_at: "2017-07-25 09:37:19">]>

感谢您的任何想法！

有关信息，我的架构：

create_table "providers", force: :cascade do |t|
  t.string "name"
  t.string "status"
  t.datetime "created_at", null: false
  t.datetime "updated_at", null: false
end

create_table "providers_users", id: false, force: :cascade do |t|
  t.bigint "provider_id", null: false
  t.bigint "user_id", null: false
  t.index ["provider_id", "user_id"], name: "index_providers_users_on_provider_id_and_user_id"
  t.index ["user_id", "provider_id"], name: "index_providers_users_on_user_id_and_provider_id"
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.integer "sign_in_count", default: 0, null: false
  t.datetime "current_sign_in_at"
  t.datetime "last_sign_in_at"
  t.inet "current_sign_in_ip"
  t.inet "last_sign_in_ip"
  t.datetime "created_at", null: false
  t.datetime "updated_at", null: false
  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

这是日志

  ÈStarted POST "/providers" for 127.0.0.1 at 2017-07-25 11:49:27 +0200
  Processing by ProvidersController#create as HTML
    Parameters: {"utf8"=>"✓", "authenticity_token"=>"27O2Tz4bbqhfRmcuq+0DIZMebSaYVc6IO/uy889Z48fF1l3c8GfIZ+WcQvZKfUeEIB5+YbrM9dON2RH47p3TIQ==", "provider"=>{"name"=>"My new provider"}, "commit"=>"Sauvegarder"}
    User Load (0.4ms)  SELECT  "users".* FROM "users" WHERE "users"."id" = $1 ORDER BY "users"."id" ASC LIMIT $2  [["id", 5], ["LIMIT", 1]]
     (0.2ms)  BEGIN
    SQL (0.4ms)  INSERT INTO "providers" ("name", "status", "created_at", "updated_at") VALUES ($1, $2, $3, $4) RETURNING "id"  [["name", "My new provider"], ["status", "name"], ["created_at", "2017-07-25 09:49:27.837165"], ["updated_at", "2017-07-25 09:49:27.837165"]]
     (4.0ms)  COMMIT
  Redirected to http://localhost:3000/providers/18/steps.location
  Completed 302 Found in 12ms (ActiveRecord: 5.0ms)


  Started GET "/providers/18/steps.location" for 127.0.0.1 at 2017-07-25 11:49:27 +0200
  Processing by Providers::StepsController#index as 
    Parameters: {"provider_id"=>"18"}
  Redirected to http://localhost:3000/providers/18/steps/registration
  Completed 302 Found in 2ms (ActiveRecord: 0.0ms)


  Started GET "/providers/18/steps/registration" for 127.0.0.1 at 2017-07-25 11:49:27 +0200
  Processing by Providers::StepsController#show as HTML
    Parameters: {"provider_id"=>"18", "id"=>"registration"}
    Provider Load (0.3ms)  SELECT  "providers".* FROM "providers" WHERE "providers"."id" = $1 LIMIT $2  [["id", 18], ["LIMIT", 1]]
    Rendering providers/steps/registration.html.haml within layouts/provider
    User Load (0.3ms)  SELECT "users".* FROM "users" INNER JOIN "providers_users" ON "users"."id" = "providers_users"."user_id" WHERE "providers_users"."provider_id" = $1  [["provider_id", 18]]
    Rendered providers/steps/registration.html.haml within layouts/provider (13.2ms)
    Rendered shared/_head.html.haml (30.6ms) [cache miss]
    User Load (0.5ms)  SELECT  "users".* FROM "users" WHERE "users"."id" = $1 ORDER BY "users"."id" ASC LIMIT $2  [["id", 5], ["LIMIT", 1]]
    Rendered shared/_header.html.haml (9.7ms) [cache miss]
  Completed 200 OK in 69ms (Views: 64.7ms | ActiveRecord: 1.1ms)

Answer 1

我知道也许这不是最好的解决方案，但它是我想到的最快的

  def create
    @provider = current_user.providers.create(provider_params)
    if @provider.id
      redirect_to root_path
    else
      render :new
    end
  end

这将创建连接表记录，当你只使用new时，为什么在属于if的情况下提供者属于用户并且在迁移中有user_id current_user.providers.new将在新实例中添加user_id，以防有和属于许多你可以这样做，也许有更好的方法，但这是我首先想到的。

或类似的东西

 def create
    @provider = Provider.new(provider_params)
    if @provider.save
      current_user.providers << @provider
      redirect_to root_path
    else
      render :new
    end
  end

还有一行，但我觉得看起来更干净。

Answer 2

def create
  @provider = current_user.providers.new(provider_params)
  @provider.users = [current_user]
  if @provider.save
    redirect_to root_path
  else
    render :new
  end
end

我建议使用has_many through关系而不是has_many_and_belongs_to，因为您可以查询连接表，如果需要，可能会在此连接表中添加更多列。

P.S。这对我来说就像一个Rails bug /功能改进。不再需要@provider.users = [current_user]，因为@provider = current_user.providers.new(provider_params)已经可以推断出@provider对象已经与current_user相关联，因此应该已经自动分配了has_many。这已经适用于itertools。似乎仅在HABTM中它不会自动分配。

协会不会在2个模型之间保存

2 个答案: