ruby on rails-nested_form、collection_select、accepts_nested_a

Question

更新：根据本问题末尾发布的堆栈跟踪，我认为真正的问题是弄清楚什么是attr_accessible，并建立关联设置，以便让贡献者和链接者属性用新的isbn id更新。请帮我

继这个问题之后。。。

我在isbn和贡献者这两个模型之间有一个连接表，它们之间有一种多对多的关系。我想在使用fields_for的嵌套表单中，在collection_select下拉列表中使用贡献者模型中的现有值。

因此，当我创建一个新的isbn时，我不想创建新的贡献者记录——我希望能够选择现有的记录。我希望能够选择许多贡献者，这就是为什么我使用nested_form gem，它允许我为贡献者动态创建额外的表单字段。

我的问题是：我应该调用联接表上的方法吗？如果是这样的话，为什么我会得到一个"丢失块"错误，尽管几乎所有的东西都是attr_accessible和accepts_nested_attributes_for:

isbn.rb:

  attr_accessible :linkers_attributes, :contributors_attributes, :contributor_id,
  has_many   :linkers
  has_many   :contributors, :through => :linkers
  accepts_nested_attributes_for :contributors
  accepts_nested_attributes_for :linkers

contributor.rb:

attr_accessible :linkers_attributes, :isbns_attributes 
  has_many :linkers
  has_many :isbns, :through => :linkers
  accepts_nested_attributes_for :isbns
  accepts_nested_attributes_for :linkers

linker.rb:

belongs_to :isbn
  belongs_to :contributor
  accepts_nested_attributes_for :contributor
  accepts_nested_attributes_for :isbn
  attr_accessible :isbn_id, :contributor_id, :isbns_attributes, :contributors_attributes, :contributor_attributes, :isbn_attributes

isbns控制器：

def new
    @isbn  = Isbn.new
    @title = "Create new ISBN"
    1.times {@isbn.linkers.build}
  end

new.html.erb:

<td class="main">
<%= nested_form_for @isbn, :validate => false do |f| %>
<h1>Create new ISBN</h1>
<%= render 'shared/error_messages', :object => f.object %>
<%= render 'fields', :f => f %>
  <div class="actions">
    <%= f.submit "Create" %>
  </div>  

_字段：（选项1）

<%= f.fields_for :contributors do |contributor_form| %>
<li>
<%= contributor_form.label 'Contributor Name' %>
<%= contributor_form.collection_select(:isbn_id, Contributor.all, :id, :personnameinverted ) %>
</li>
<%= contributor_form.link_to_remove "[-] Remove this contributor"%>
<% end %>
<%= f.link_to_add "[+] Add a contributor", :contributors  %>

这将创建一个新的ISBN，并在链接器中创建一个具有正确ISBN_id的新记录，但在实际希望新链接器记录包含现有的contributor_id时，还会在贡献者中创建一条新记录。所以我想我会这么做：

_字段（选项2）

<%= field_set_tag 'Contributor' do %>
<li>
<%= f.label 'Contributor Sequence Number' %>
<%= f.text_field :descriptivedetail_contributor_sequencenumber%>
<%= tooltip(:xxx, :hover) %>
</li>
<%= f.fields_for :linkers do |contributor_form| %>
<li>
<%= contributor_form.label 'Contributor Name' %>
<%= contributor_form.collection_select(:isbn_id,  Contributor.all, :id, :personnameinverted ) %>
</li>
<%= contributor_form.link_to_remove "[-] Remove this contributor"%>
<% end %>
<%= f.link_to_add "[+] Add a contributor", :contributors  %>

但这会返回一个丢失的块错误。

非常感谢，我已经花了整整两天的时间在这件事上，我想我可能会崩溃。

更新：这是一条线索，来自这个新代码的堆栈跟踪，因为我认为你实际上不能在联接表上调用一个方法：

<%= f.fields_for :contributors do |contributor_form| %>
<li>
<%= contributor_form.collection_select(:id, Contributor.all, :id, :personnameinverted, :include_blank => true ) %>

Started POST "/isbns" for 127.0.0.1 at 2011-06-08 20:12:48 +0100
  Processing by IsbnsController#create as HTML
  Parameters: {"utf8"=>"✓", "authenticity_token"=>"u0TszLESOnZlr4iEiBlVg6w9B5T+EH0dxJg/0E6PKuQ=", "isbn"=>{"descriptivedetail_titledetail_titleelement_titleprefix"=>"", "descriptivedetail_titledetail_titleelement_titlewithoutprefix"=>"qqq", "istc_id"=>"471", "descriptivedetail_contributor_sequencenumber"=>"", "contributors_attributes"=>{"0"=>{"id"=>"1", "_destroy"=>"false"}, "1307560328932"=>{"id"=>"14", "_destroy"=>"false"}}, "descriptivedetail_contributor_contributorrole"=>""}, "commit"=>"Create"}
  User Load (0.2ms)  SELECT "users".* FROM "users" WHERE "users"."id" = 2 LIMIT 1
  Contributor Load (0.3ms)  SELECT "contributors".* FROM "contributors" INNER JOIN "linkers" ON "contributors".id = "linkers".contributor_id WHERE "contributors"."id" IN (1, 14) AND (("linkers".isbn_id = NULL))
Completed   in 308ms

因此，看起来实际上是在设置贡献者id，但链接器表没有传递isbn id。继续。。。

Answer 1

好吧。以下是我的做法。

安装茧宝石。终于抽出时间安装了Haml，

我将新的和更新的操作分开，所以新表单只是快速获取id集，只需要最少的字段。然后用户可以编辑它，并添加贡献者。从用户的角度来看，这实际上并不坏，因为他们可以快速创建isbn，而无需填写大量字段。

isbns/new.html.haml

%td.main
= semantic_form_for @isbn do |f|
  %h1 Create new ISBN
  = render 'shared/error_messages', :object => f.object
  = render 'fields', :f => f
  %div#actions
  = f.submit "Create"

isbns/_fields.html.haml

- f.inputs do
  = f.input :istc_id, :as => :select, :collection => Istc.all
  = f.input :descriptivedetail_titledetail_titleelement_titlewithoutprefix
  %h3 Contributors
  #tasks
    = f.semantic_fields_for :linkers do |linker|
      = render 'linker_fields', :f => linker
    .links
      = link_to_add_association 'add contributor', f, :linkers
  -f.buttons do
    = f.submit 'Save'

isbns/_linker_fields.html.haml

.nested-fields
  = f.inputs do
    = f.input :contributor_id, :label_method => :keynames, :as => :select, :collection => Contributor.all
    = link_to_remove_association "remove contributor", f

Isbn.rb

  has_many :linkers
  has_many :contributors, :through => :linkers
  accepts_nested_attributes_for :contributors, :allow_destroy => true
  accepts_nested_attributes_for :linkers, :allow_destroy => true

贡献者.rb

  attr_accessible :linkers_attributes, :isbns_attributes
  has_many :isbns, :through => :linkers
  has_many :linkers
  accepts_nested_attributes_for :linkers

链接.rb

belongs_to :contributor
belongs_to :isbn
accepts_nested_attributes_for :contributor

中的结果

Started POST "/isbns/58" for 127.0.0.1 at 2011-06-09 12:34:14 +0100
  Processing by IsbnsController#update as HTML
  Parameters: {"utf8"=>"✓", "authenticity_token"=>"u0TszLESOnZlr4iEiBlVg6w9B5T+EH0dxJg/0E6PKuQ=", "isbn"=>{"istc_id"=>"360", "descriptivedetail_titledetail_titleelement_titlewithoutprefix"=>"thurs title", "linkers_attributes"=>{"0"=>{"contributor_id"=>"3", "_destroy"=>"", "id"=>"68"}, "1"=>{"contributor_id"=>"71", "_destroy"=>"", "id"=>"69"}, "2"=>{"contributor_id"=>"72", "_destroy"=>"", "id"=>"70"}, "3"=>{"contributor_id"=>"3", "_destroy"=>"", "id"=>"71"}}}, "commit"=>"Save", "id"=>"58"}
  User Load (0.2ms)  SELECT "users".* FROM "users" WHERE "users"."id" = 2 LIMIT 1
  Isbn Load (8.2ms)  SELECT "isbns".* FROM "isbns" WHERE "isbns"."id" = 58 ORDER BY descriptivedetail_titledetail_titleelement_titlewithoutprefix LIMIT 1
  Linker Load (0.3ms)  SELECT "linkers".* FROM "linkers" WHERE "linkers"."id" IN (68, 69, 70, 71) AND ("linkers".isbn_id = 58)
  AREL (0.4ms)  UPDATE "linkers" SET "contributor_id" = 3, "updated_at" = '2011-06-09 11:34:14.509943' WHERE "linkers"."id" = 71
  Contributor Load (158.3ms)  SELECT "contributors".* FROM "contributors"
Redirected to http://localhost:3000/isbns/58
Completed 302 Found in 545ms

换句话说，从一个动态生成嵌套字段的isbn编辑表单中，使用formtastic，我可以使用下拉菜单选择一个与isbn有多对多关系的现有贡献者。

Phew。