Rails: validating a field is present only if another is present
activerecord, ruby, ruby-on-rails, validation
Solution
You can use a Proc on the `:activated_at` validator.
validates :activated_at, :presence, if: Proc.new { |a| a.is_activated? }
Recommended Reading:
- http://guides.rubyonrails.org/active_record_validations.html#using-a-proc-with-if-and-unless
- http://api.rubyonrails.org/classes/ActiveRecord/Validations/ClassMethods.html
Finally, you should consider renaming `:is_activated` to simply `:activated`. This is considered better practice in Rails. The `is_` prefix is used in other languages for boolean attributes because their method names don't support a `?` character. Ruby does, and Rails generates `___?` methods on boolean attributes. Because of this it's better to just call the attribute `:activated` and check it with `activated?`.
Problem
I have a model where there are two fields that can technically be null. The field names are `:is_activated` and `:activated_at`. `:activated_at` is only required if `:is_activated` is set to `true`. It does not need to be present if `:is_activated` is `false`. What's the appropriate way in Rails to set this validation directly into ActiveRecord?