Ruby on Rails的：在索引視圖中顯示來自相關聯的模型中的一個屬性值

Question

我想有顯示所述相關聯的項目名稱（從分貝項目字段）從has_many_through元素索引視圖和experimenttype（從分貝實驗場）和屬於/有許多關聯模型

模型element.rb

class Element < ActiveRecord::Base 

has_many :project_elements 
has_many :projects, :through => :project_elements 

has_many :experiments 

attr_accessible :project_ids, :experiment_ids 

模型project.rb

class Project < ActiveRecord::Base 

has_many :project_elements 
has_many :elements, :through => :project_elements 

attr_accessible :projectname, :element_ids 

模型project_elem ent.rb

class ProjectElement < ActiveRecord::Base 
belongs_to :project 
belongs_to :element 
attr_accessible :project_id, :element_id 

模型experiment.rb

class Experiment < ActiveRecord::Base 

belongs_to :element 

has_many :welldish_experiments 
has_many :welldishs, :through => :welldish_experiments 

attr_accessible :exptype, :element_id 

elements_controller.rb

def index 
    @elements = Element.all 
    respond_to do |format| 
    format.html # index.html.erb 
    format.json { render json: @elements } 
    end 

/elements/index.html.erb

<% @elements.each do |element| %> 
    <tr> 

    <td><%= element.experiments %></td> 
    <td><%= element.projects %></td>  

當我這樣做它向我展示了整個相關的項目對象... 相同的實驗 和我不知道如何限制顯示爲一個單一的屬性？

替代地因爲使用formtastic中生成的所述DATAS的：

元件/ _form.html.erb

 <%= semantic_form_for @element do |f| %>  
     <%= f.inputs do %> 
     <%= f.input :projects, :label => "projet associé", :required => true%> 
     <%= f.input :experiments, :label => "type d'experience", 
    :as => :radio,  :collection => Experiment.all, :required => true %>  
     <% end %> 
     <%= f.actions :submit, :cancel %> 
     <% end %> 

我不知道是否有從那裏一個快速的方法來生成索引圖（有一些？渲染「形式」選項也許） 任何幫助，將不勝感激......

Answer 1

答案在這裏（收集法）： http://api.rubyonrails.org/classes/ActiveRecord/Associations/ClassMethods.html

<% @elements.each do |element| %> 
     <tr>   
     <td><%= element.projects.collect { |a| a.projectname }%></td> 
     </tr> 
    <% end %>