Question

我正在尝试做一些我认为应该非常简单的事情。我有四个模型如下：

class Checkout < ActiveRecord::Base
  has_many :checkedout_items
  belongs_to :student, :autosave => true
  attr_accessible :student_id, :status, :checkedout_items_attributes, :student_attributes, :status
  accepts_nested_attributes_for :checkedout_items
  accepts_nested_attributes_for :student
end

class CheckedoutItem < ActiveRecord::Base
  belongs_to :checkout, :autosave => true
  has_one :item, :foreign_key => "id"
  attr_accessible :enddate, :checkout_id, :item_id, :startdate, :status, :item_attributes
  accepts_nested_attributes_for :item
end

class Item < ActiveRecord::Base
  attr_accessible :name, :category
end

class Student < ActiveRecord::Base
  has_many :checkouts, dependent: :destroy
  attr_accessible :email, :firstname, :lastname, :phonenumber, :uin
end

我希望有一个表单，最终用户可以在一个表单中创建学生和checkedout_items。所以，我有一个创建表单并生成以下哈希结构的视图：

{"utf8"=>"✓",
 "authenticity_token"=>"m6yH1LhtOk/kDqpLDRlNkxFSAA1WmGARywgT4DwYmKo=",
 "checkout"=> {
   "student_attributes"=> {
     "firstname"=>"Jimmy",
     "lastname"=>"Johnson",
     "uin"=>"899006555",
     "email"=>"jj@test.com",
     "phonenumber"=>"1234445555"
   },
   "checkedout_items_attributes"=> {
     "0"=> {
       "item_attributes"=> {
         "id"=>"1",
         "name"=>"Camera #1"
       },
       "startdate(2i)"=>"12",
       "startdate(3i)"=>"8",
       "startdate(1i)"=>"2014",
       "startdate(4i)"=>"04",
       "startdate(5i)"=>"00"
     },
     "1"=> {
       "item_attributes"=> {
         "id"=>"2",
         "name"=>"Camera #2"
       },
       "startdate(2i)"=>"12",
       "startdate(3i)"=>"8",
       "startdate(1i)"=>"2014",
       "startdate(4i)"=>"04",
       "startdate(5i)"=>"00"
     }
   }
 },
"commit"=>"Finish"}

当这些数据发布到我的控制器时，我尝试按如下方式创建一个新的结帐对象：

@checkout = Checkout.new(params[:checkout])

但是，这会导致错误：“对于ID =”的CheckedoutItem，找不到ID = 1的项目。我试图寻找与此相关的其他问题，但我找不到太多。

最后一个关键信息是，在创建结账之前，项应始终存在，因此数据库中已存在ID为1和2的项。谁能提供一些关于出了什么问题的见解？

编辑：控制器方法：

def create
    @checkout = Checkout.new(params[:checkout])

    respond_to do |format|
      if @checkout.save
        format.html { redirect_to @checkout, notice: 'Checkout was successfully created.' }
        format.json { render json: @checkout, status: :created, location: @checkout }
      else
        format.html { render action: "new" }
        format.json { render json: @checkout.errors, status: :unprocessable_entity }
      end
    end
  end

错误：

Couldn't find Item with ID=2 for CheckedoutItem with ID=

部分追踪：

activerecord (3.2.16) lib/active_record/nested_attributes.rb:487:in `raise_nested_attributes_record_not_found'
activerecord (3.2.16) lib/active_record/nested_attributes.rb:357:in `assign_nested_attributes_for_one_to_one_association'
activerecord (3.2.16) lib/active_record/nested_attributes.rb:313:in `item_attributes='
activerecord (3.2.16) lib/active_record/attribute_assignment.rb:94:in `block in assign_attributes'
activerecord (3.2.16) lib/active_record/attribute_assignment.rb:93:in `each'
activerecord (3.2.16) lib/active_record/attribute_assignment.rb:93:in `assign_attributes'
activerecord (3.2.16) lib/active_record/base.rb:498:in `initialize'
activerecord (3.2.16) lib/active_record/reflection.rb:183:in `new'
activerecord (3.2.16) lib/active_record/reflection.rb:183:in `build_association'
activerecord (3.2.16) lib/active_record/associations/association.rb:239:in `build_record'
activerecord (3.2.16) lib/active_record/associations/collection_association.rb:112:in `build'
activerecord (3.2.16) lib/active_record/nested_attributes.rb:430:in `block in assign_nested_attributes_for_collection_association'
activerecord (3.2.16) lib/active_record/nested_attributes.rb:425:in `each'
activerecord (3.2.16) lib/active_record/nested_attributes.rb:425:in `assign_nested_attributes_for_collection_association'
activerecord (3.2.16) lib/active_record/nested_attributes.rb:313:in `checkedout_items_attributes='
activerecord (3.2.16) lib/active_record/attribute_assignment.rb:94:in `block in assign_attributes'
activerecord (3.2.16) lib/active_record/attribute_assignment.rb:93:in `each'
activerecord (3.2.16) lib/active_record/attribute_assignment.rb:93:in `assign_attributes'
activerecord (3.2.16) lib/active_record/base.rb:498:in `initialize'

Rails版本：3.2.16

Answer 1

如果将来有人遇到这种情况，我可以使用本文所述的方法来解决这个问题：https://stackoverflow.com/a/12064875/2443892。

Rails嵌套属性中的一些已经存在导致数据库查询

1 个答案: