ruby-on-rails - Rails has_many through 似乎不起作用

Question

我需要对这个进行第二次观察。当我在两个玩家之间创建匹配时，Tournament.players 返回一个空数组。

代码

class Tournament < ActiveRecord::Base
  has_many :player_matches
  has_many :matches
  has_many :players, :through => :player_matches  
end

class PlayerMatch < ActiveRecord::Base
  belongs_to :player
  belongs_to :match
  belongs_to :tournament
end

class Player < ActiveRecord::Base
  has_many :player_matches
  has_many :matches, :through => :player_matches
  has_many :tournaments, :through => :player_matches
end

Answer 1

您需要有双重:through关系：

player_matches通过matches和players通过player_matches。

class Tournament < ActiveRecord::Base
  has_many :matches
  has_many :player_matches, :through => :matches
  has_many :players, :through => :player_matches  
end

class PlayerMatch < ActiveRecord::Base
  belongs_to :player
  belongs_to :match
end

class Player < ActiveRecord::Base
  has_many :player_matches
  has_many :matches, :through => :player_matches
  has_many :tournaments, :through => :player_matches
end

class Match < ActiveRecord::Base
  belongs_to :tournament  
  has_many :player_matches
  has_many :players, :through => :player_matches
end