Question

我想弄清楚如何最好地做我的模型关联。我有3张桌子。

玩家，团队， teamplayers

我的大纲是玩家可以属于多个团队。一个团队可以拥有多个玩家，但是在我的teamplayers表中我有2个字段 teamid 和 playerid （不包括主键ID）。

例如：

Player has id of 1000
team has id of 501

在teamplayers表中，将存储为：

 team_id    player_id
  501        1000

那么我如何在模型中设计关系 belongs_to 和 has_many ？

Answer 1

以下应该做：

class Player < ActiveRecord::Base
  has_many :team_players
  has_many :teams, through: :team_players
end

class TeamPlayer < ActiveRecord::Base
  belongs_to :player
  belongs_to :team
end

class Team < ActiveRecord::Base
  has_many :team_players
  has_many :players, through: :team_players
end

Answer 2

你希望has_many通过关联。

class Player < ActiveRecord::Base
  has_many :teamplayers
  has_many :teams, through: :teamplayers
end

class TeamPlayer < ActiveRecord::Base
  belongs_to :player
  belongs_to :team
end

class Team < ActiveRecord::Base
  has_many :teamplayers
  has_many :players, through: :teamplayers
end

http://guides.rubyonrails.org/association_basics.html

Answer 3

您可以按照以下方式实现此目的：

class Team < ActiveRecord::Base
  has_many :team_players
  has_many :players, :through => :team_players
end

class Player < ActiveRecord::Base
  has_many :team_players
  has_many :teams, :through => :team_players
end

class TeamPlayer < ActiveRecord::Base
  belongs_to :player
  belongs_to :team
end

相应的迁移可能如下所示：

class CreateTeamPlayers < ActiveRecord::Migration
  def change
    create_table :teams do |t|
      t.string :name
      t.timestamps
    end

    create_table :players do |t|
      t.string :name
      t.timestamps
    end

    create_table :team_players do |t|
      t.belongs_to :player
      t.belongs_to :team
      t.timestamps
    end
  end
end

然后，如果您想要获取特定团队的玩家，请执行

@team = Team.first (do as per your requirement)
@team.players

另外，要获取球员的球队，

@player = Player.first (do as per your requirement)
@player.teams

H2H：） -

Answer 4

这可以通过两种方式实现：

首先是：

class Team < ActiveRecord::Base
   has_and_belongs_to_many :players
end

class Player < ActiveRecord::Base
   has_and_belongs_to_many :teams
end

第二是：

class Player < ActiveRecord::Base
   has_many :teamplayers
   has_many :teams, through: :teamplayers
end

class TeamPlayer < ActiveRecord::Base
   belongs_to :player
   belongs_to :team
end

class Team < ActiveRecord::Base
   has_many :teamplayers
   has_many :players, through: :teamplayers
end

Rails Active Record中的模型关联澄清

4 个答案: