Rails 3中数据建模帮助 - 有很多，属于，嵌套Atrributes [英] Rails 3 Data Modeling Help - Has Many, Belongs to, Nested Atrributes

问题描述

我的工作涉及三个型号（收件人，奖，播音员）的一个项目，需要有一个嵌套的属性由播音员给多个收件人发出一个奖项时。举个例子，奖励形式必须做的三件事情的能力：

I am working on a project involving three models (recipient, award, announcer) and need to have a nested attributes when issuing an award by an announcer to multiple recipients. For an example, award form need to have the ability to do 3 things:

1. 可以添加多个收受人（即添加收件人，删除收件人） - 嵌套的属性
2. 创建一个新的奖项之后，该奖项将被张贴到收件人的个人资料。
3. 启用的未来投票@ recipient.awards和@ announcer.awards

真正的如何巧妙地解决这个问题方面的斗争。中大奖的形式：收件人accepts_nested_attributes_for下面的数据结构，一种是有道理的，但不能做。你能帮我吗？提前很多感谢。

Really struggle in terms of how to smartly solve this problem. The following data structure kind of made sense, however can not do "accepts_nested_attributes_for :recipients" in the award form. Can you help? Many thanks in advance.

类收件人＆LT;的ActiveRecord :: Base的

class Recipient < ActiveRecord::Base

• 的has_many：奖项
• 的has_many：播音员，：通过=>：奖项

结束

类播音员＆LT;的ActiveRecord :: Base的

class Announcer < ActiveRecord::Base

• 的has_many：奖项
• 的has_many：收件人：通过=>：奖项

结束

类奖＆LT;的ActiveRecord :: Base的

class Award < ActiveRecord::Base

• belongs_to的：播音员
• belongs_to的：收件人

结束

推荐答案

你只是在那里。主要的问题是，你正在尝试的形式，而不是仅仅创造奖和其他对象（用户）之间的关系，创建收件人对象。你可以做这样的事情：

You're just about there. The main issue is that you're trying to create recipient objects in the form rather than just creating a relationship between the award and another object (user). You could do something like this:

class User < ActiveRecord::Base
  has_many :recipients
  has_many :awards, :through => :recipients
end

# this is your relationship between an award and a user
class Recipient < ActiveRecord::Base
  belongs_to :user
  belongs_to :award
end

class Award < ActiveRecord::Base
  has_many :recipients
  has_many :users, :through => :recipients
  belongs_to :announcer

  accepts_nested_attributes_for :recipients, :allow_destroy => true
end

class Announcer < ActiveRecord::Base
  has_many :awards
  has_many :recipients, :through => :awards
end

然后你只需做一个嵌套形式，将建立recipients_attributes数组：

Then you would just do a nested form that would build the recipients_attributes array:

<%= form_for @award do |f| %>

  <%= f.text_field :name %>

  <div id="recipients">
    <% @award.recipients.each do |recipient| %>

     <%= render :partial => '/recipients/new', :locals => {:recipient => recipient, :f => f} %>

    <% end %>
  </div>
  <%= link_to_function 'add recipient', "jQuery('#recipients').append(#{render(:partial => '/recipients/new').to_json})" %>

<% end %>

和，使其保持干燥只是把部分嵌套到部分：

And, to keep it DRY just push the nested part into a partial:

# app/views/recipients/_new.html.erb
<% recipient ||= Recipient.new %>
<%= f.fields_for 'recipients_attributes[]', recipient do |rf| %>
  <%= rf.select :user_id, User.all %>
  <%= fr.check_box '_delete' %>
  <%= fr.label '_delete', 'remove' %>
<% end %>

显然User.all通话是不理想的，所以也许作出这样的自动完成。

Obviously the User.all call isn't ideal so maybe make that an autocomplete.

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