Mongoid-同一异域的两个域逆 [英] Mongoid - two fields inverses of the same foreign field

问题描述

我正在尝试使以下Mongoid关系起作用，但是每个团队的游戏领域都是一个空数组.这不是有效的关系模型吗?我需要拆分游戏，即home_games和away_games吗?

I'm trying to get the following Mongoid relationships to work, but the game field of each team is an empty array. Is this not a valid relational model? Do I need to split up games, i.e. home_games and away_games?

class Team
  include Mongoid::Document

  has_many :games, :autosave => true

end

class Game
  include Mongoid::Document

  belongs_to :home_team, :class_name => "Team", :inverse_of => :games
  belongs_to :away_team, :class_name => "Team", :inverse_of => :games

end

推荐答案

我不认为有直接的方法可以做到这一点，也许您可​​以通过以下方法解决此问题

I dont think so there is a straight way to do this, may be you workaround by

class Team
  include Mongoid::Document

  has_many :home_played, :class_name => 'Game' , :inverse_of => :home_team
  has_many :away_played, :class_name => 'Game' , :inverse_of => :away_team


 def games
    Game.any_of({:home_team_id => self.id},{:away_team_id => self.id})
 end

end

class Game
  include Mongoid::Document

  belongs_to :home_team, :class_name => "Team", :inverse_of => :home_played
  belongs_to :away_team, :class_name => "Team", :inverse_of => :away_played

end

所以现在您可以像使用它

so now you can use it like

g = Game.new
+--------------------------+-------+--------------------------+--------------+--------------+
| _id                      | _type | _id                      | home_team_id | away_team_id |
+--------------------------+-------+--------------------------+--------------+--------------+
| 4ec76f70b356f8031f000001 |       | 4ec76f70b356f8031f000001 |              |              |
+--------------------------+-------+--------------------------+--------------+--------------+
1 row in set
>> t=Team.new
+--------------------------+-------+--------------------------+
| _id                      | _type | _id                      |
+--------------------------+-------+--------------------------+
| 4ec76f75b356f8031f000002 |       | 4ec76f75b356f8031f000002 |
+--------------------------+-------+--------------------------+
1 row in set
>> t.save
=> true
g.home_team = t
+--------------------------+-------+--------------------------+
| _id                      | _type | _id                      |
+--------------------------+-------+--------------------------+
| 4ec76f75b356f8031f000002 |       | 4ec76f75b356f8031f000002 |
+--------------------------+-------+--------------------------+
1 row in set
>> g.save
=> true

和

>> Team.first.home_played
+--------------------------+-------+--------------------------+--------------------------+--------------+
| _id                      | _type | _id                      | home_team_id             | away_team_id |
+--------------------------+-------+--------------------------+--------------------------+--------------+
| 4ec76f70b356f8031f000001 |       | 4ec76f70b356f8031f000001 | 4ec76f75b356f8031f000002 |              |
+--------------------------+-------+--------------------------+--------------------------+--------------+
1 row in set
>> Game.first.home_team
+--------------------------+-------+--------------------------+
| _id                      | _type | _id                      |
+--------------------------+-------+--------------------------+
| 4ec76f75b356f8031f000002 |       | 4ec76f75b356f8031f000002 |
+--------------------------+-------+--------------------------+

您可以通过以下方式获取总数

abd you can get the total count by

>> Team.first.games

希望这会有所帮助

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