ruby-on-rails - 在 Rails 中命名多对多关系

Question

我应该如何在 Rails 3.2 中创建以下模型？项目可以有 1+ 个所有者和 1+ 个用户。它们都是 Person 类的实例。我已经考虑过，has_and_belongs_to_many但我不知道如何为每个项目处理两个单独的 Persons 集合。

Answer 1

您将需要一个连接模型来表示每个has-and-belongs-to-many关系，并且您可以使用has-many-through如下所述进行访问：

class ProjectOwnerLink < ActiveRecord::Base
  belongs_to :project
  belongs_to :owner, class_name: 'Person'
end

class ProjectUserLink < ActiveRecord::Base
  belongs_to :project
  belongs_to :user, class_name: 'Person'
end

class Project < ActiveRecord::Base
  has_many :project_owner_links
  has_many :owners, :through => :project_owner_links
  has_many :project_user_links
  has_many :users, :through => :project_user_links
end

class Person < ActiveRecord::Base
  has_many :project_owner_links
  has_many :owned_projects, :through => :project_owner_links, :source => :project
  has_many :project_user_links
  has_many :used_projects, :through => :project_user_links, :source => :project
end

Answer 2

下面是演示应用程序。

https://github.com/diatmpravin/habtm-demo.git

请看一下，如果您有任何问题，请告诉我？

Answer 3

您可以定义另一个模型Participation来保存关系的类型，即用户的角色。（未经测试）代码：

class Project < ActiveRecord::Base
  has_many :participations
  has_many :users, :through => :participations

  def with_role(role)
    includes(:participations).where('participation.role = ?', role)
  end

  def owners
    users.with_role('owner')
  end

  def participants
    users.with_role('participant')
  end
end

 

class User < ActiveRecord::Base
  has_many :participations
  has_many :projects, :through => :participations

  def with_role(role)
    includes(:participations).where('participation.role = ?', role)
  end

  def projects_owned
    projects.with_role('owner')
  end

  def projects_participating_in
    projects.with_role('participant')
  end
end

 

class Participation < ActiveRecord::Base
  # has an attribute 'role'

  belongs_to :project
  belongs_to :user
end