Question

我正在开展涉及三个模型（收件人，奖励，播音员）的项目，并且当播音员向多个收件人发放奖励时需要具有嵌套属性。举个例子，奖励表格需要有能力做三件事：

可以添加多个收件人（即“添加收件人”，“删除收件人”） - 嵌套属性
创建新奖项后，该奖项将发布到收件人的个人资料中。
启用@ recipient.awards和@ announcer.awards

在如何巧妙地解决这个问题方面真的很挣扎。以下数据结构有意义，但不能在奖励表单中执行“accepts_nested_attributes_for：recipients”。你能帮我吗？非常感谢提前。

类收件人＆lt;的ActiveRecord ::基

has_many：awards
has_many：播音员，：through =＆gt; ：奖励

端

类播音员＆lt;的ActiveRecord ::基

has_many：awards
has_many：收件人，：via =＆gt; ：奖励

端

班级奖＆lt;的ActiveRecord ::基

belongs_to：播音员
belongs_to：收件人

端

Answer 1

你就在那里。主要问题是您尝试在表单中创建收件人对象，而不是仅仅创建奖励与另一个对象（用户）之间的关系。你可以这样做：

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

然后你只需要一个嵌套的表单来构建recipients_attributes数组：

<%= 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 %>

并且，为了保持DRY，只需将嵌套部分推入部分：

# 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调用并不理想，所以可能会自动完成。

Rails 3数据建模帮助 - Has_many，属于嵌套属性

1 个答案: