How to remove validation using instance_eval clause in Rails?

Question

I would like to enhance existing class using instance_eval. There original definition contains validation, which require presence of certain fields, ie:

class Du         


        

Answer 1

If you doesn't want to make any changes in Parent class then first clear all validations in child class and copy all required validation from parent class to child class

  class Dummy < ActiveRecord::Base
      validates :property, presence: true
      validates :value, length: { maximum: 255 }
  end

And override it in child class

Dummy.class_eval do    
  clear_validators!
  validates :property, presence: true
end