RoR：从 AR 扩展的模型中的 ActiveRecord、NoMethodError

Question

我设置了以下模型：

class Qa::Base < ActiveRecord::Base
  self.abstract_class = true
  Qa::Base.establish_connection("qa_audit_#{RAILS_ENV}")
end

类 Qa::ErrorType # 关联 has_many :errors, :class_name => 'Qa::Error' has_many :evaluations, :class_name => 'Qa::Evaluation', :through => :errors
# 验证 validates_presence_of ：内容 validates_uniqueness_of ：内容 结尾

但是在保存/验证模型时，我不断遇到以下 NoMethodErrors：

<pre>NoMethodError (undefined method `add_on_blank' for #Class:0x23a3020):</pre>

例如：

e = Qa::ErrorType.first

e.valid?

生产

NoMethodError: undefined method add_on_blank' for #<Class:0x223eeb4>
    from /opt/local/lib/ruby/gems/1.8/gems/activerecord-2.3.8/lib/active_record/base.rb:1994:inmethod_missing_without_paginate'
    from /opt/local/lib/ruby/gems/1.8/gems/will_paginate-2.3.14/lib/will_paginate/finder.rb:170:in method_missing'
    from /opt/local/lib/ruby/gems/1.8/gems/activerecord-2.3.8/lib/active_record/associations/association_collection.rb:380:insend'
    from /opt/local/lib/ruby/gems/1.8/gems/activerecord-2.3.8/lib/active_record/associations/association_collection.rb:380:in method_missing_without_paginate'
    from /opt/local/lib/ruby/gems/1.8/gems/activerecord-2.3.8/lib/active_record/base.rb:2178:inwith_scope'
    from /opt/local/lib/ruby/gems/1.8/gems/activerecord-2.3.8/lib/active_record/associations/association_proxy.rb:207:in send'
    from /opt/local/lib/ruby/gems/1.8/gems/activerecord-2.3.8/lib/active_record/associations/association_proxy.rb:207:inwith_scope'
    from /opt/local/lib/ruby/gems/1.8/gems/activerecord-2.3.8/lib/active_record/associations/association_collection.rb:376:in method_missing_without_paginate'
    from /opt/local/lib/ruby/gems/1.8/gems/will_paginate-2.3.14/lib/will_paginate/finder.rb:170:inmethod_missing'
    from /opt/local/lib/ruby/gems/1.8/gems/activerecord-2.3.8/lib/active_record/validations.rb:599:in validates_presence_of'
    from /opt/local/lib/ruby/gems/1.8/gems/activesupport-2.3.8/lib/active_support/callbacks.rb:182:incall'
    from /opt/local/lib/ruby/gems/1.8/gems/activesupport-2.3.8/lib/active_support/callbacks.rb:182:in evaluate_method'
    from /opt/local/lib/ruby/gems/1.8/gems/activesupport-2.3.8/lib/active_support/callbacks.rb:166:incall'
    from /opt/local/lib/ruby/gems/1.8/gems/activesupport-2.3.8/lib/active_support/callbacks.rb:90:in run'
    from /opt/local/lib/ruby/gems/1.8/gems/activesupport-2.3.8/lib/active_support/callbacks.rb:90:ineach'
    from /opt/local/lib/ruby/gems/1.8/gems/activesupport-2.3.8/lib/active_support/callbacks.rb:90:in send'
    from /opt/local/lib/ruby/gems/1.8/gems/activesupport-2.3.8/lib/active_support/callbacks.rb:90:inrun'
    from /opt/local/lib/ruby/gems/1.8/gems/activesupport-2.3.8/lib/active_support/callbacks.rb:276:in run_callbacks'
    from /opt/local/lib/ruby/gems/1.8/gems/activerecord-2.3.8/lib/active_record/validations.rb:1110:invalid_without_callbacks?'
    from /opt/local/lib/ruby/gems/1.8/gems/activerecord-2.3.8/lib/active_record/callbacks.rb:315:in `valid?'

我之前在同一应用程序的其他地方使用过相同的代码模式，并且该部分仍然可以正常工作（所有验证都按预期工作）。

有人能解释一下我做错了什么吗？

Answer 1

找出问题所在：

class Qa::ErrorType < Qa::Base
  set_table_name "error_types"

  # Associations
  has_many :errors, :class_name => 'Qa::Error'
  has_many :evaluations, :class_name => 'Qa::Evaluation', :through => :errors

  # Validations
  validates_presence_of :content
  validates_uniqueness_of :content
end

此声明覆盖 ActiveRecord 提供的错误关联/对象，因此我们放弃了 ActiveRecord::Validations 提供的所有验证功能。将关联重命名为更具体的事物可以解决问题。

类的正确实现：

class Qa::ErrorType < Qa::Base
  set_table_name "error_types"

  # Associations
  has_many :transaction_errors, :class_name => 'Qa::TransactionError'
  has_many :evaluations, :class_name => 'Qa::Evaluation', :through => :transaction_errors

  # Validations
  validates_presence_of :content
  validates_uniqueness_of :content
end

在此更改之后，所有验证都将按原样进行。我认为将类 Qa::Error 重命名为 Qa::TransactionError 是可选的。我只是这样做了，所以我的命名约定在整个应用程序中是一致的。