ActiveRecord::RecordInvalid：验证失败：团队必须存在

Question

我在运行rake db:seed 时收到错误ActiveRecord::RecordInvalid: Validation failed: Team must exist。

我正在尝试在玩家和团队之间建立关联。我有数据要播种到我的数据库中，但我不确定错误是由我如何设置关联或我如何构建数据引起的。

Team 是父级，Player 是子级。

型号

# player.rb
class Player < ApplicationRecord
  belongs_to :team, class_name: "Player"

  validates :team, presence: true, allow_nil: true
end


# team.rb
class Team < ApplicationRecord
  has_many :players
end

路线

# routes.rb
Rails.application.routes.draw do
  get 'welcome/index'

  resources :players

  resources :teams do
    resources :players
  end

  root 'welcome#index'
end

迁移

# create_players.rb
class CreatePlayers < ActiveRecord::Migration[5.1]
  def change
    create_table :players do |t|
      t.belongs_to :team, index: true

      t.string :name

      t.string :shoots
      t.string :catches
      t.string :position
      t.string :pos
      t.integer :number
      t.integer :gp
      t.integer :goals
      t.integer :assists
      t.integer :points
      t.integer :pim
      t.integer :plusMinus
      t.decimal :gaa
      t.integer :svs

      t.integer :team_id
      t.references :teams

      t.timestamps
    end
  end
end


# create_teams.rb
class CreateTeams < ActiveRecord::Migration[5.1]
  def change
    create_table :teams do |t|

      t.string :team_name
      t.string :abr
      t.string :sm_logo
      t.string :lg_logo

      t.integer :player_id

      t.timestamps
    end
  end
end

尝试播种的数据示例

# Player data
players = Player.create!({
  "name": "Some Guy",
  "shoots": "Right",
  "position": "Forward",
  "pos": "F",
  "number": 8,
  "gp": 15,
  "goals": 12,
  "assists": 6,
  "points": 18,
  "pim": 12,
  "plusMinus": 7,
  "team_id": 1
})


# Team data
teams = Team.create!({
  "team_name": "A Team",
  "abr": "ATM"
})

宝石文件

source 'https://rubygems.org'

gem 'rails', '~> 5.1.0'
gem 'pg', '~> 0.18'
gem 'puma', '~> 3.7'
gem 'sass-rails', '~> 5.0'
gem 'uglifier', '>= 1.3.0'
# See https://github.com/rails/execjs#readme for more supported runtimes
# gem 'therubyracer', platforms: :ruby

#Bootstrap 4 and Tether gems
gem 'bootstrap', '~> 4.0.0.alpha6'
gem 'rails-assets-tether', '>= 1.3.3', source: 'https://rails-assets.org'

gem 'turbolinks', '~> 5'
gem 'jbuilder', '~> 2.5'
gem 'rails-ujs', '~> 0.1.0'
gem 'jquery-rails'
# Use ActiveModel has_secure_password
# gem 'bcrypt', '~> 3.1.7'

# Use Capistrano for deployment
# gem 'capistrano-rails', group: :development

group :development, :test do
  # Call 'byebug' anywhere in the code to stop execution and get a debugger console
  gem 'byebug', platforms: [:mri, :mingw, :x64_mingw]
end

group :development do
  # Access an IRB console on exception pages or by using <%= console %> anywhere in the code.
  gem 'web-console', '>= 3.3.0'
  gem 'listen', '>= 3.0.5', '< 3.2'
  # Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
  gem 'spring'
  gem 'spring-watcher-listen', '~> 2.0.0'
end

# Windows does not include zoneinfo files, so bundle the tzinfo-data gem
gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]

Answer 1

首先你需要创建团队：

team = Team.create!({ team_name: "A Team", abr: "ATM" })

请注意，我将hash 传递给create! 方法，而不是像您在示例中那样使用散列的array。

然后您可以创建玩家并将其添加到团队中：

player = Player.create!({
  "name": "Some Guy",
  "shoots": "Right",
  "position": "Forward",
  "pos": "F",
  "number": 8,
  "gp": 15,
  "goals": 12,
  "assists": 6,
  "points": 18,
  "pim": 12,
  "plusMinus": 7,
  "team": team
})

请注意，我可以将 team 对象传递给 Player.create! 方法。这将使玩家与团队相关联。否则你可以只使用id。

player = Player.create!({
  ...
  team_id: team.id
})

或

player = Player.create!({
  ...
  team_id: 1
})

省略号（3 个点）应替换为如上所示的实际属性。

更新

从 create_players.rb 迁移中删除以下行：

  t.integer :teams_id
  t.references :teams

从 create_teams.rb 迁移中删除以下行：

  t.integer :player__id

写入t.belongs_to :player 产生与写入t.integer :player_id 相同的结果。它只是 Rails 的语法糖。写t.belongs_to :player 或t.references :player 只是比写t.integer :player_id 更清楚一点

我假设您希望一名球员属于一支球队（一对多的关系）。如果您认为一个玩家可能属于多个团队（通常情况并非如此，但我不知道您正在开发什么），那么您需要在 Google 上搜索 Rails 多对多关系。

Answer 2

@Greg 回答感谢您的帮助。我现在找到了一个可行的解决方案。

为了解决这个问题，我恢复到以前的提交并决定遵循以下文章： https://www.learneroo.com/modules/137/nodes/767

我完成的工作代码如下所示：

型号

# Team model
class Team < ApplicationRecord
  has_many :players
end

# Player model
class Player < ApplicationRecord
  belongs_to :team
end

迁移

# create_teams.rb
class CreateTeams < ActiveRecord::Migration[5.1]
  def change
    create_table :teams do |t|

      t.string :team_name
      t.string :abr

      t.timestamps
    end
  end
end

# create_players.rb
class CreatePlayers < ActiveRecord::Migration[5.1]
  def change
    create_table :players do |t|
      t.string :name
      t.string :shoots
      t.string :catches
      t.string :position
      t.string :posAbr
      t.string :abr
      t.integer :number
      t.integer :gp
      t.integer :goals
      t.integer :assists
      t.integer :points
      t.integer :pim
      t.integer :plusMinus
      t.decimal :gaa
      t.integer :svs

      t.timestamps
    end
  end
end

# add_team_id_to_players.rb
class AddTeamIdToPlayers < ActiveRecord::Migration[5.1]
  def change
    add_column :players, :team_id, :integer
  end
end

种子数据示例

# Team data
teams = Team.create([{
  "team_name": "A Team",
  "abr": "ATM"
}])

# Player data
players = Player.create!([{
  "name": "Some Guy",
  "shoots": "Right",
  "position": "Forward",
  "pos": "F",
  "number": 8,
  "gp": 15,
  "goals": 12,
  "assists": 6,
  "points": 18,
  "pim": 12,
  "plusMinus": 7,
  "team_id": 1
}])

Answer 3

你在class Player的关联是错误的，看看什么时候一定要用：

如果其他模型的名称不能从关联名称派生，您可以使用 :class_name 选项来提供模型名称。例如，如果一本书属于某个作者，但包含作者的模型的实际名称是 Patron，您可以这样设置：

class Book < ApplicationRecord
  belongs_to :author, class_name: "Patron"
end

查看使用此关联的所有选项：Rails Guide