与accepts_nested_attributes_for麻烦的验证外键 [英] Trouble with accepts_nested_attributes_for on validating foreign key

问题描述

我使用Ruby on Rails的V3.2.2。我想解决使用 accepts_nested_attributes_for 和 validates_associated RoR的方法时，涉及到外键的验证问题。也就是说，我有以下模型类：

 类文章＆LT;的ActiveRecord :: Base的
  的has_many：category_associations，：foreign_key =＆GT; CATEGORY_ID

  accepts_nested_attributes_for：category_associations，：reject_if =＆GT;拉姆达{|属性|属性[：CATEGORY_ID] .blank？ }
  validates_associated：category_associations
结束

类CategoryAssociation＆LT;的ActiveRecord :: Base的
  belongs_to的：文章：foreign_key =＆GT; 的article_id
  belongs_to的：类别：foreign_key =＆GT; CATEGORY_ID

  验证：article_id的，：presence =＆GT;真正
  验证：CATEGORY_ID，：presence =＆GT;真正
结束
 

......，我有以下控制措施：

 类ArticlesController＆LT;的ApplicationController
  高清新
    @article = Article.new
    5.times {@ article.category_associations.build}

    ＃...
  结束

 DEF创建
   @article = Article.new（PARAMS [：文章]）

   如果@ article.save
     ＃...
   其他
     ＃...
   结束
 结束
结束
 

通过上面的code（启发由嵌套模式组成部分1 Rails的角色）的我的意图是建立一个文章的时候存储类别关联的（注意的：类对象已经present在数据库中;在我的情况，我想只是存储创造类别关联）。然而，当我从相关视图文件提交相关表格，我得到以下错误（我记录错误消息）：

  {：category_associations.article_id=＆GT;不能为空]：category_associations =＆GT;无效]}
 

为什么会发生，因为 validates_associated <一个href="http://stackoverflow.com/questions/5176510/validates-associated-not-checking-existence-of-associations#comment5826558_5176607">seems运行的方法 article.category_association.valid？但只有当 article.category_association.article_id 是不的零？我该如何解决与的article_id 外键的presence验证问题？

不过，如果我注释掉验证：article_id的，：presence =＆GT;真正的在 CategoryAssociation 模型类，它的工作原理是预期，但<一个href="http://stackoverflow.com/questions/13345250/is-it-really-needed-to-validate-foreign-keys/13346791#13346791">it似乎是的没有的一个正确的方法做的没有的验证外键的。

---

如果我注释掉 validates_associated：在文章模型类category_associations ，我仍然得到错误：

  {：category_associations.article_id=＆GT;不能为空]}
 

解决方案

使用 inverse_of 链接协会和验证presence关联的对象，而不是实际的外键presence。

从的文档：

 类会员＆LT;的ActiveRecord :: Base的
  的has_many：帖子，i​​nverse_of：会员
  accepts_nested_attributes_for：帖子
结束

类岗位＆LT;的ActiveRecord :: Base的
  belongs_to的：会员，inverse_of：帖子
  validates_ presence_of：成员
结束
 

I am using Ruby on Rails v3.2.2. I would like to solve the issue related to the validation of a foreign key when using accepts_nested_attributes_for and validates_associated RoR methods. That is, I have following model classes:

class Article < ActiveRecord::Base
  has_many :category_associations, :foreign_key => 'category_id'

  accepts_nested_attributes_for :category_associations, :reject_if => lambda { |attributes| attributes[:category_id].blank? }
  validates_associated :category_associations
end

class CategoryAssociation < ActiveRecord::Base
  belongs_to :article, :foreign_key => 'article_id'
  belongs_to :category, :foreign_key => 'category_id'

  validates :article_id, :presence => true
  validates :category_id, :presence => true
end

... and I have following controller actions:

class ArticlesController < ApplicationController
  def new
    @article = Article.new
    5.times { @article.category_associations.build }

    # ...
  end

 def create
   @article = Article.new(params[:article])

   if @article.save
     # ...
   else
     # ...
   end
 end
end

With the above code ("inspired" by the Nested Model Form Part 1 Rails Cast) my intent is to store category associations when creating an article (note: category objects are already present in the database; in my case, I would like just storing-creating category associations). However, when I submit the related form from the related view file, I get the following error (I am logging error messages):

{:"category_associations.article_id"=>["can't be blank"], :category_associations=>["is invalid"]}

Why it happens since validates_associated seems to run the method article.category_association.valid? but only if the article.category_association.article_id is not nil? How can I solve the problem with the presence validation of the article_id foreign key?

However, if I comment out the validates :article_id, :presence => true in the CategoryAssociation model class, it works as expected but it seems to be not a right approach to do not validate foreign keys.

---

If I comment out the validates_associated :category_associations in the Article model class, I still get the error:

{:"category_associations.article_id"=>["can't be blank"]}

解决方案

Use inverse_of to link the associations and validate the presence of the associated object, NOT the presence of the actual foreign key.

Example from the docs:

class Member < ActiveRecord::Base
  has_many :posts, inverse_of: :member
  accepts_nested_attributes_for :posts
end

class Post < ActiveRecord::Base
  belongs_to :member, inverse_of: :posts
  validates_presence_of :member
end

这篇关于与accepts_nested_attributes_for麻烦的验证外键的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！