module ActiveRecord::AttributeMethods

def respond_to?(name, include_private = false)

person.respond_to?(:nothing) # => false
person.respond_to?('age?') # => true
person.respond_to?('age=') # => true
person.respond_to?('age') # => true
person.respond_to?(:name?) # => true
person.respond_to?(:name=) # => true
person.respond_to?(:name) # => true
person = Person.new

end
class Person < ActiveRecord::Base

not been generated.
which will all return +true+. It also defines the attribute methods if they have
person.respond_to?(:name=), and person.respond_to?(:name?)
A Person object with a name attribute can ask person.respond_to?(:name), 
def respond_to?(name, include_private = false)
  return false unless super
  # If the result is true then check for the select case.
  # For queries selecting a subset of columns, return false for unselected columns.
  # We check defined?(@attributes) not to issue warnings if called on objects that
  # have been allocated but not yet initialized.
  if defined?(@attributes)
    if name = self.class.symbol_column_to_string(name.to_sym)
      return _has_attribute?(name)
    end
  end
  true
end