我尝试将用户类型更改为＆＃34; nil＆＃34;并继续收到此错误消息：
单表继承机制无法找到子类：＆＃39; nil＆＃39;。提出此错误是因为列＆＃39;键入＆＃39;保留用于存储继承的类。如果您不打算将此列用于存储继承类或覆盖User.inheritance_column以使用另一列来获取该信息，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'
我理解它为什么会发生，我确实希望单表继承发生，但它甚至不让我覆盖它Rails控制台。我试图将用户类型更改回我需要的内容，并立即向我提供该消息。即使我使用User.find（ myID ），它也不会提取我的数据。
我可以告诉它覆盖它并更改类型吗？
编辑：
我试过了：
User.last (I was the last user)
User.find(*myId*)
它甚至不让我User.last.destroy或User.destroy_all，在控制台中每次都给出同样的错误。
我还尝试创建一个名为＆＃34; nil＆＃34;继承自用户，但仍然没有。
答案 0 :(得分：3)
嗯，你搞砸了一点：）
滑轨＆＃39;单表继承需要type字段中的确切类名。由于"nil"未指定有效的User子类，因此您创建的对象在STI方面毫无意义。
很容易解决。选择所有错误条目（包含"nil"中的type）并修复它们（将type设置为nil，这将成为SQL NULL，这意味着＆＃34 ;基类＆＃34;这里）：
User.where(type: "nil").update_all(type: nil)