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我有用户和项目资源以及连接它们的连接表，称为 project_members。我希望在所有用户离开项目时具有功能，项目会自行销毁，如下面的规范：

 75     it 'deletes the project when there are no more users on it' do
 76       lambda do
 77         project.users.clear 
 78       end.should change(Project, :count).by(-1)
 79     end

到目前为止，我想出了这条线，但不知道放在哪里......

@project.destroy if @project.users.empty?

编辑：这是我的模型

用户模型（我正在使用设计）

  1 class User < ActiveRecord::Base
  2 
  3   has_many :synapses #aka project_members      
  4   has_many :projects, :through => :synapses
  5 
  6   # Include default devise modules. Others available are:
  7   # :token_authenticatable, :encryptable, :lockable, :timeoutable and :omniauthable
  8   devise :database_authenticatable, :registerable,
  9          :recoverable, :rememberable, :trackable, :validatable,
 10          :confirmable      
 11   
 12   # Setup accessible (or protected) attributes for your model
 13   attr_accessible :email, :password, :password_confirmation, :remember_me
 14 end

项目模型

  1 class Project < ActiveRecord::Base
  2 
  3   has_many :synapses
  4   has_many :users, :through => :synapses, :dependent => :nullify
  5   has_many :tasks, :dependent => :destroy
  6 
  7   #use this when you don't have callbacks
  8   #has_many :tasks, :dependent => :delete_all
  9 
 10   validates :name, :presence => true,
 11             :uniqueness => true
 12   validates :description, :presence => true
 13 
 14   attr_accessible :name, :description
 15 
 16 end

突触模型 AKA（项目成员）

  1 class Synapse < ActiveRecord::Base
  2 
  3   belongs_to  :user,
  4               :class_name => 'User',          
  5               :foreign_key => 'user_id'       
  6   belongs_to  :project,
  7               :class_name => 'Project',       
  8               :foreign_key => 'project_id'    
  9   
 10 end

任务模型

  1 class Task < ActiveRecord::Base
  2 
  3   belongs_to :project
  4   belongs_to :user
  5 
  6   validates :name, :presence => true
  7   validates :description, :presence => true,
  8                           :length => { :minimum => 10 }
  9 
 10   attr_accessible :name, :description
 11 
 12 end
4

2 回答 2

1

成员模型上的回调应该这样做：

class ProjectMember < ActiveRecord::Base
  after_destroy :remove_project_if_last_member
  private
    def remove_project_if_last_member
      project.destroy if project.users.empty?
    end
end
于 2012-05-07T21:48:46.857 回答
1

首先，您的关系陈述可以简化：

belongs_to  :user,
  :class_name => 'User',          
  :foreign_key => 'user_id'

可以变得简单

belongs_to  :user

和属性默认:class_name为:foreign_key您拥有它们。

如果最后一个用户离开项目，您应该在 Synapses 类上放置一个回调来销毁项目。像这样的东西：

class Synapse < ActiveRecord::Base

  after_destroy :remove_project_if_last_member

  private

  def remove_project_if_last_member
    project.destroy if project.users.empty?
  end

end

[注意：我从另一个答案中复制了 after_destroy 回调——如果那个已经很好了，那么编造一些东西是没有意义的。]

于 2012-05-07T22:10:50.830 回答