Question

我有当前的模特关系：

class Group < ActiveRecord::Base
  has_many :group_memberships, dependent: :destroy
  has_many :subjects, through: :group_memberships
  has_many :entries, through: :group_memberships
  accepts_nested_attributes_for :group_memberships, allow_destroy: true

class GroupMembership < ActiveRecord::Base
  belongs_to :group
  belongs_to :subject
  belongs_to :entry

class Issue < ActiveRecord::Base
  has_many :group_memberships, through: :entries, dependent: :destroy
  has_many :groups, through: :group_memberships, dependent: :destroy
  accepts_nested_attributes_for :group_memberships, allow_destroy: true, reject_if: :all_blank
  accepts_nested_attributes_for :groups, allow_destroy: true

使用cocoon嵌套字段和simpleform - 当我添加或更新现有对象时 - 创建了两个不完整的group_membership记录（即它们将所需的外键分成两个模型。

这和我通常使用的关联之间的唯一区别是，在这种情况下，连接表有三个外键而不是两个。

SQL查询：

INSERT INTO `groups` (`name`, `created_at`, `updated_at`) VALUES ('test group', '2016-01-11 15:53:22', '2016-01-11 15:53:22')
INSERT INTO `group_memberships` (`subject_id`, `group_id`, `created_at`, `updated_at`) VALUES (16, 18, '2016-01-11 15:53:22', '2016-01-11 15:53:22')
INSERT INTO `group_memberships` (`entry_id`, `group_id`, `created_at`, `updated_at`) VALUES (20, 18, '2016-01-11 15:53:22', '2016-01-11 15:53:22')

控制器中的参数似乎正常：

"groups_attributes"=>{"1452527593321"=>{"name"=>"test group", "subject_ids"=>["", "16"], "_destroy"=>"false"}}, "_destroy"=>"false", "id"=>"20"}

当参数显示正常时，我真的有点迷失为什么我要处理重复的不完整查询

表单本身如下所示：

<div id="groups">
  <div id="groups_from_list">
      <%= f.simple_fields_for :groups do |group| %>
        <%= render 'group_fields', :f => group %>
      <% end %>
  </div>
  <%= link_to_add_association 'add a group', f, :groups, :class => 'btn btn-primary btn' %>
</div>

通过使用嵌套表单的关联，标准has_many没有任何问题 - 但我认为在group_membership连接表中有三个外键导致了问题。

**Group Fields Partial**

<div class="nested-fields">
  <%= f.input :name , input_html: { class: 'form-control-small' }, label: "Group name" %>
  <%= f.association :subjects,
                      include_blank: false,
                      label_method: :full_name,
                      label: "Attendees",
                      collection: Subject.order(:last_name),
                      input_html: { class: 'select2-issue-X' },
                      placeholder: "add attendees" %>
  <%= link_to_remove_association "remove", f, :class => 'btn btn-danger btn-xs'%>
</div>

Answer 1

我通过使用不同的模型关系来解决这个问题 - 我在原始帖子中使用的那个似乎不受标准嵌套字段实现的支持 - 尽管它可以通过重写控制器和模型代码来解决。

class Group < ActiveRecord::Base
  has_many :group_memberships, dependent: :destroy
  has_many :subjects, through: :group_memberships

class GroupMembership < ActiveRecord::Base
  belongs_to :group
  belongs_to :subject

class Issue < ActiveRecord::Base
  has_many :groups, through: :entries
  has_many :group_memberships, through: :groups, dependent: :destroy
  accepts_nested_attributes_for :groups, allow_destroy: true

具有has_many到关系的嵌套字段 - 重复不完整的记录

1 个答案: