Question

我对rails非常陌生，并试图让三个模型与has_many through关系一起工作，在连接模型上使用备用类名，并使用collection_select表单向连接模型添加记录。这三个型号如下。我对所有协会都有“accepts_nested_attributes_for”。

用户模型

has_many :match_opponents
has_many :home_opponents, :class_name => 'MatchOpponent', :foreign_key => 'home_opponent_id'
has_many :away_opponents, :class_name => 'MatchOpponent', :foreign_key => 'away_opponent_id'
has_many :matches, :through => :match_opponents

匹配模型

has_many :match_opponents
has_many :home_opponents, :class_name => 'MatchOpponent', :foreign_key => 'home_opponent_id'
has_many :away_opponents, :class_name => 'MatchOpponent', :foreign_key => 'away_opponent_id'
has_many :users, :through => :match_opponents

匹配对手模型

belongs_to :user, :inverse_of => :match_opponents
belongs_to :match, :inverse_of => :match_opponents

我的匹配控制器for new和create：

def new
  @match = Match.new
  @match.home_opponents.build
  @match.away_opponents.build
end

def create
  @match = Match.create(match_params)
  @home_opponents = @match.home_opponents.create!(params[:match_opponents])
  @away_opponents = @match.away_opponents.create!(params[:match_opponents])
  if @match.save 
    redirect_to @match, notice: 'Match was successfully created.'
  end
end

我的表格：

= simple_form_for @match, html: { multipart: true } do |f|
  = simple_fields_for :home_opponents do |ff|
    = ff.collection_select :user_id, User.all, :id, :name, {}, {multiple: true}

  = simple_fields_for :away_opponents do |ff|
    = ff.collection_select :user_id, User.all, :id, :name, {}, {multiple: true}

每个型号的相关允许参数：

def match_params
  params.require(:match).permit(Match::MATCH_ATTRIBUTES)
end

MATCH_ATTRIBUTES = [:match_opponent_ids => [], :user_ids => [], match_opponents_attributes: MatchOpponent::MATCH_OPPONENT_ATTRIBUTES]

def user_params
  params.require(:user).permit(User::USER_ATTRIBUTES)
end

USER_ATTRIBUTES = [:match_opponent_ids => [], :match_ids => [], :match_opponents_attributes: MatchOpponent::MATCH_OPPONENT_ATTRIBUTES]

def match_opponent_params
  params.require(:match_opponent).permit(MatchOpponent::MATCH_OPPONENT_ATTRIBUTES)
end

MATCH_OPPONENT_ATTRIBUTES = [:id, :home_opponent_id, :away_opponent_id, :match_id, :user_id]

我尝试了很多不同的模型配置，但是无法在连接模型（MatchOpponent）上获得多条记录来保存记录的match_id和user_id。

提前感谢您的帮助！

Answer 1

首先，您需要了解有关控制器操作的更多信息。您可以在Rails Guides

中了解相关信息

例如：

def create
  @match = Match.create(match_params)
  @home_opponents = @match.home_opponents.create!(params[:match_opponents])
  @away_opponents = @match.away_opponents.create!(params[:match_opponents])
  if @match.save 
    redirect_to @match, notice: 'Match was successfully created.'
  end
end

Match.create已经保存了对象，您可以使用if @match.save再次保存该对象。这应该是：

def create
  @match = Match.new(match_params)
  if @match.save 
    #create opponents here
    redirect_to @match, notice: 'Match was successfully created.'
  end
end

Answer 2

谢谢！用以下解决了这个问题。需要在User模型上而不是在连接模型（MatchOpponent）上创建备用类：

用户模型

has_many :match_opponents
has_many :matches, :through => :match_opponents
has_many :home_opponents, :through => :match_opponents
has_many :away_opponents, :through => :match_opponents

匹配模型

has_many :match_opponents
has_many :home_opponents, :through => :match_opponents
has_many :away_opponents, :through => :match_opponents

匹配对手模型

belongs_to :home_opponent, :class_name => 'User', :foreign_key => 'home_opponent_id'
belongs_to :away_opponent, :class_name => 'User', :foreign_key => 'away_opponent_id'
belongs_to :match, :inverse_of => :match_opponents

以上所有都有accepts_nested_attributes_for。

我的匹配控制器for new和create：

def new
  @match = Match.new
end

def create
  @match = Match.new(match_params)
  @match.update!(:status => 'pending')
  if @match.save 
    @match.match_opponents.where.not(:home_opponent_id => 'nil').each do |o| o.update!(:user_id => o.home_opponent_id) end
    @match.match_opponents.where.not(:away_opponent_id => 'nil').each do |o| o.update!(:user_id => o.away_opponent_id) end
   redirect_to @match, notice: 'Match was successfully created.'
  end
end

我的表格：

= f.collection_select :home_opponent_ids, User.order(:first_name), :id, :name, {}, {multiple: true}
= f.collection_select :away_opponent_ids, User.order(:first_name), :id, :name, {}, {multiple: true}

rails has_many通过collection_select创建多个连接记录

2 个答案: