Rails的单表继承的ActiveRecord :: SubclassNotFound

Question

我试图改变用户类型设置为“无”，并不断得到现在这个错误消息：

的单表继承机制未能找到该子类：“零” 。出现此错误的原因是“类型”列在保留继承的情况下保留用于存储类。如果您不打算将其用于存储继承类或覆盖User.inheritance_column以使用其他列来处理该信息，请重命名此列。

from /usr/local/rvm/gems/ruby-2.0.0-p481@rails-4.0.2/gems/activerecord-4.1.1/lib/active_record/inheritance.rb:161:in `rescue in find_sti_class' 
from /usr/local/rvm/gems/ruby-2.0.0-p481@rails-4.0.2/gems/activerecord-4.1.1/lib/active_record/inheritance.rb:155:in `find_sti_class' 
from /usr/local/rvm/gems/ruby-2.0.0-p481@rails-4.0.2/gems/activerecord-4.1.1/lib/active_record/inheritance.rb:144:in `discriminate_class_for_record' 
from /usr/local/rvm/gems/ruby-2.0.0-p481@rails-4.0.2/gems/activerecord-4.1.1/lib/active_record/persistence.rb:50:in `instantiate' 
from /usr/local/rvm/gems/ruby-2.0.0-p481@rails-4.0.2/gems/activerecord-4.1.1/lib/active_record/querying.rb:48:in `block in find_by_sql' 
from /usr/local/rvm/gems/ruby-2.0.0-p481@rails-4.0.2/gems/activerecord-4.1.1/lib/active_record/result.rb:55:in `block in each' 
from /usr/local/rvm/gems/ruby-2.0.0-p481@rails-4.0.2/gems/activerecord-4.1.1/lib/active_record/result.rb:55:in `each' 
from /usr/local/rvm/gems/ruby-2.0.0-p481@rails-4.0.2/gems/activerecord-4.1.1/lib/active_record/result.rb:55:in `each' 
from /usr/local/rvm/gems/ruby-2.0.0-p481@rails-4.0.2/gems/activerecord-4.1.1/lib/active_record/querying.rb:48:in `map' 
from /usr/local/rvm/gems/ruby-2.0.0-p481@rails-4.0.2/gems/activerecord-4.1.1/lib/active_record/querying.rb:48:in `find_by_sql' 
from /usr/local/rvm/gems/ruby-2.0.0-p481@rails-4.0.2/gems/activerecord-4.1.1/lib/active_record/relation.rb:603:in `exec_queries' 
from /usr/local/rvm/gems/ruby-2.0.0-p481@rails-4.0.2/gems/activerecord-4.1.1/lib/active_record/relation.rb:487:in `load' 
from /usr/local/rvm/gems/ruby-2.0.0-p481@rails-4.0.2/gems/activerecord-4.1.1/lib/active_record/relation.rb:231:in `to_a' 
from /usr/local/rvm/gems/ruby-2.0.0-p481@rails-4.0.2/gems/bullet-4.13.1/lib/bullet/active_record41.rb:10:in `to_a' 
from /usr/local/rvm/gems/ruby-2.0.0-p481@rails-4.0.2/gems/activerecord-4.1.1/lib/active_record/relation/finder_methods.rb:479:in `find_last' 
from /usr/local/rvm/gems/ruby-2.0.0-p481@rails-4.0.2/gems/activerecord-4.1.1/lib/active_record/relation/finder_methods.rb:165:in `last' 

我明白为什么它的发生，我确实希望出现的单表继承，但它甚至不会让我重写它的Rails控制台。我正在尝试将用户类型改回我需要的类型，并立即向我提供该信息。即使我做User.find（myID）它不会拉我的数据。

任何方式，我可以告诉它重写它，并改变类型？

编辑：

我想：

User.last (I was the last user) 

User.find(*myId*) 

它甚至不会让我做User.last.destroy或User.destroy_all，给了我同样的错误在控制台每次上面。

我也试过创建一个名为“nil”的模型，它从用户继承而来，并且什么也没有。

Answer 1

好了，你搞砸了一点点:)

Rails的单表继承预计type场的确切类的名称。由于"nil"未指定有效的User子类，因此您已创建在STI方面没有意义的对象。

这很容易修复。选择所有errorneous项（含type"nil"）和解决这些问题（设置type到nil，这将成为SQL NULL，意思是“基地班”在这里）：

User.where(type: "nil").update_all(type: nil)