试图读取属性从加盟模式时，没有得到方法错误 [英] Getting no method error when trying to read attribute from join model

问题描述

我有项目，用户可以通过的has_many加盟：通过加盟模式称为所有权。每个所有权的拥有，我要访问一个owner_type属性。

I have projects and users joined via has_many :through join model called ownerships. Each ownership has an owner_type attribute that I want to access.

我希望有一种方式来传递一个user_ID的一个项目模型，并得到通过所有权owner_type加盟模式。反之亦然我想通过一个PROJECT_ID到用户模式并获得通过所有权owner_type加盟模式。以下是我有：

I want to have a way to pass a user_id to a project model and get the owner_type via the ownership join model. And visa versa I want to pass a project_id to a user model and get the owner_type via the ownership join model. Here is what I have:

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

  has_many :ownerships
  has_many :users, :through => :ownerships

  validates :name, :presence => true,
                   :length => { :maximum => 50 }

  def owner_type?(user_id)
    @user_id = user_id
    @ownership = self.ownerships.where(:user_id => @user_id)
    @ownership.owner_type
  end

end

class User < ActiveRecord::Base
  attr_accessible :name, :email, :admin

  has_many :ownerships
  has_many :projects, :through => :ownerships

  accepts_nested_attributes_for :projects

  email_regex = /\A[\w+\-.]+@[a-z\d\-.]+\.[a-z]+\z/i

  validates :name, :presence => true,
                   :length => { :maximum => 50 }

  #validates :email, :presence => true,
  #                  :format => { :with => email_regex },
  #                  :uniqueness => { :case_sensitive => false }

  validates_inclusion_of :admin, :in => [true, false]

  def self.create_with_omniauth(auth)
    create! do |user|
      user.provider = auth["provider"]
      user.uid = auth["uid"]
      user.name = auth["user_info"]["name"]
      user.admin = false
    end
  end
end

class Ownership < ActiveRecord::Base
  attr_accessible :owner_type

  belongs_to :project
  belongs_to :user

  validates :user_id, :presence => true

  validates :project_id, :presence => true

  validates :owner_type, :presence => true

end

，然后在我的项目＃显示页面：

and then in my project#show page:

<%= @project.owner_type?(current_user.id) %>

我是什么做错了吗？如何从任何地方访问从所有制模式的owner_type属性？它从来就行不通。

what am I doing wrong? How do I access the owner_type attribute from the ownership model from anywhere? It never works.

推荐答案

您还没有粘贴你所得到的实际误差。但在这里就是我的想法是怎么了。

You haven't pasted the actual error you are getting. But here is what I think is going wrong.

所有权是的has_many 的关系。它会回报你的结果集合，始终。因此， @ownership = self.ownerships.where（：USER_ID =＆GT; @user_id）将回报你一个数组。所以，如果你希望只有1结果你应该做的事情。

ownerships is a has_many relationship. It will return you a collection of results, always. Thus, @ownership = self.ownerships.where(:user_id => @user_id) will return you an array. So you should probably be doing if you expect only 1 result.

@ownership = ownerships.where(:user_id => @user_id).first
@ownership.owner_type

这应该工作。

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