Rails: how to require at least one field not to be blank

Question

Hi

I know I can require a field by adding validates_presence_of :field to the model. However, how do I require at least one field to be mandatory, while not requiring any particular field?

thanks in advance

-- Deb

Answer 1

Add a validate method to your model:

def validate
  if field1.blank? and field2.blank? and field3.blank? # ...
    errors.add_to_base("You must fill in at least one field")
  end
end

Answer 2

I believe something like the following may work

class MyModel < ActiveRecord::Base
   validate do |my_model|
      my_model.my_validation
   end

   def my_validation      
      errors.add_to_base("Your error message") if self.blank? 
      #or self.attributes.blank? - not sure
   end
end

Answer 3

You can use:

validate :any_present?

def any_present?
  if %w(field1 field2 field3).all?{|attr| self[attr].blank?}
    errors.add_to_base("Error message")
  end
end

But you have to provide field names manually. You could get all content columns of a model with Model.content_columns.map(&:name), but it will include created_at and updated_at columns too, and that is probably not what you want.