activerecord - Ruby-on-rails-4 和 Activerecord find_by 错误

Question

嗨，我有一个应用模型，我尝试在 rails 控制台中查找_by_hashid！

ruby -v
ruby 1.9.3p125 (2012-02-16 revision 34643) [x86_64-darwin11.1.0]
gem 'rails', '4.0.0.rc1'

我的模型：

class App < ActiveRecord::Base
  include ActiveModel::Dirty
  include Tokenable

  has_many :categories, dependent: :destroy
  before_save :notify_categories 

  def notify_categories
    self.categories.map!{|c| c.update_results(self.data)}
  end

  def to_param
    self.hashid
  end
end

在控制台中

 App.find_by_hashid "e2eed536bb2"
 App Load (0.4ms)  SELECT "apps".* FROM "apps" WHERE "apps"."hashid" = 'e2eed536bb2' LIMIT 1 => nil 

 App.where(:hashid =>"e2eed536bb2")
 App Load (0.3ms)  SELECT "apps".* FROM "apps" WHERE "apps"."hashid" = 'e2eed536bb2' => #<ActiveRecord::Relation []> 

应用程序哈希

 App.first.hashid
 App Load (0.2ms)  SELECT "apps".* FROM "apps" ORDER BY "apps"."id" ASC LIMIT 1
  => "e2eed536bb2" 

这返回真

 App.first.hashid == "e2eed536bb2"
 App Load (0.4ms)  SELECT "apps".* FROM "apps" ORDER BY "apps"."id" ASC LIMIT 1 => true 

甚至试试这个。我只有一个“应用程序”

 App.find_by_hashid(App.first.hashid)
 App Load (0.3ms)  SELECT "apps".* FROM "apps" ORDER BY "apps"."id" ASC LIMIT 1
 App Load (0.3ms)  SELECT "apps".* FROM "apps" WHERE "apps"."hashid" =      'e2eed536bb2' LIMIT 1  => nil