Can I change the validation rules required for different actions?

Question

I have a model that looks like this -

class Car < ActiveRecord::Base
  validates :name,:presence =>true
end

Can I set it up so that the car's name is not required when preforming a create action but it is required when doing an 'edit' action?

Answer 1

Yup, that's possible:

class Car < ActiveRecord::Base
  validates :name, presence: true, on: :update
end

Might have a look at the Active Record Validations and Callbacks Guide.