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创建用户时，将创建一个团队，并将用户设置为该团队的所有者，并设置为该团队的成员。

一个用户可以是多个团队的成员，而团队可以有多个成员。每个用户只能拥有一个团队，一个团队只能拥有一个所有者。

现在我有一些奇怪的行为，我可以弄清楚

1.9.3p194 :001 > user = User.first
User Load (0.1ms)  SELECT "users".* FROM "users" LIMIT 1
=> #<User id: 1, email: "test@example.com", encrypted_password: "$2a$10$KhQ7z3Qb6QXdsBA/MmPLuecrbIV4cGEaMGhIepLjuzla...", reset_password_token: nil, reset_password_sent_at: nil, remember_created_at: nil, sign_in_count: 1, current_sign_in_at: "2012-07-28 01:33:31", last_sign_in_at: "2012-07-28 01:33:31", current_sign_in_ip: "127.0.0.1", last_sign_in_ip: "127.0.0.1", created_at: "2012-07-28 01:33:31", updated_at: "2012-07-28 01:33:31"> 
1.9.3p194 :002 > user.teams
Team Load (0.1ms)  SELECT "teams".* FROM "teams" INNER JOIN "teams_users" ON "teams"."id" = "teams_users"."team_id" WHERE "teams_users"."user_id" = 1
=> [#<Team id: 1, name: "username", dept_no: nil, created_at: "2012-07-28 01:33:31", updated_at: "2012-07-28 01:33:31", user_id: 1>] 
1.9.3p194 :003 > user.owned_team
Team Load (0.2ms)  SELECT "teams".* FROM "teams" WHERE "teams"."user_id" = 1 LIMIT 1
=> #<Team id: 1, name: "username", dept_no: nil, created_at: "2012-07-28 01:33:31", updated_at: "2012-07-28 01:33:31", user_id: 1>

到目前为止，一切都按预期工作，但是当我尝试从另一端访问关联时，没有建立连接。

见下文，我提取了与 user.owned_team 和 user team.owner 相同的团队记录，它返回 nil

1.9.3p194 :004 > team = Team.first
Team Load (0.1ms)  SELECT "teams".* FROM "teams" LIMIT 1
=> #<Team id: 1, name: "username", dept_no: nil, created_at: "2012-07-28 01:33:31", updated_at: "2012-07-28 01:33:31", user_id: 1> 
1.9.3p194 :005 > team.owner
=> nil 
1.9.3p194 :006 > user.owned_team == team.owner
=> false 
1.9.3p194 :007 >

用户.rb

class User < ActiveRecord::Base

  has_and_belongs_to_many :teams
  has_one :owned_team, :class_name => "Team"

  after_create :set_user_on_team

  private

  def set_user_on_team
    self.owned_team = self.teams.create(:name => 'username' ) 
  end
end

团队.rb

class Team < ActiveRecord::Base

  attr_accessible :name
  has_and_belongs_to_many :users
  belongs_to :owner, :class_name => "User"

end
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1 回答 1

1

我认为您在某处缺少外键声明。

假设您在 team 表中有一个 owner_id 字段：

class User < ActiveRecord::Base
  has_one :owned_team, :class_name => "Team", :foreign_key => 'owner_id'
end

class Team < ActiveRecord::Base
  belongs_to :owner, :class_name => "User", :foreign_key => 'owner_id'
end

这样，当您访问两个链接时，rails 知道如何提取数据

于 2012-07-28T01:57:08.830 回答