class ActiveRecord::UnknownAttributeError 
        Active Model UnknownAttributeError
Raised when unknown attributes are supplied via mass assignment.
class Person
  include ActiveModel::AttributeAssignment
  include ActiveModel::Validations
end
person = Person.new
person.assign_attributes(name: 'Gorby')
# => ActiveModel::UnknownAttributeError: unknown attribute 'name' for Person.
    Inherits From
- 
          class
          
NoMethodError 
Attributes
| [R] | attribute | 
            |
| [R] | record | 
            
Public class methods
Source code GitHub
# File activemodel/lib/active_model/errors.rb, line 538
def initialize(record, attribute)
  @record = record
  @attribute = attribute
  super("unknown attribute '#{attribute}' for #{@record.class}.")
end