ruby-on-rails - has_many 通过范围条件

Question

我是 Rails 的新手，有一个关于为has_many :through关系设置条件的问题。我想在模型中建立:joined_groups关系。FacebookUserjoin_groups 将是一个通过 GroupInvite 表满足的条件where(accepted: true)。但是我不知道如何使用 Rails 来实现这一点，或者这是否是正确的方法。我有以下型号...

组.rb

class Group < ActiveRecord::Base
  attr_accessible :description, :name

  ...

  #Relationships
  has_many :group_invites, class_name: 'GroupInvite'
  has_many :facebook_users, class_name: 'FacebookUser', :through => :group_invites, :source => :facebook_user
end

GroupInvite.rb

class GroupInvite < ActiveRecord::Base
  attr_accessible :accepted, :facebook_user_uid, :group_id, :admin

  ...    

  #Relationships
  belongs_to :group
  belongs_to :facebook_user, :foreign_key => :facebook_user_uid, :primary_key => :facebook_user_uid

  #Scopes
  scope :pending, where(accepted: nil)
  scope :declined, where(accepted: false)
  scope :joined, where(accepted: true)
end

Facebook的用户

class FacebookUser < ActiveRecord::Base

  #Attributes
  attr_accessible :first_name, :gender, :last_name, :uid

  ...

  has_many :group_invites, class_name: 'GroupInvite', :primary_key => :uid, :foreign_key => :facebook_user_uid
  has_many :groups, class_name: 'Group', :through => :group_invites, :source => :group
  ...
end

任何帮助将不胜感激！

Answer 1

你可以试试这个：

has_many :accepted_group_invites, class_name: 'GroupInvite', :primary_key => :uid, :foreign_key => :facebook_user_uid, :conditions => { :accepted => true }

马塔