rails text_field / text_ara empty string vs nil

Question

I'm not even sure if I have a problem, but I just don't like that my text_fields and text_areas get saved in the db as empty string instead of nil.

I'm playing with the null object pattern and just realized if I create a profile but don't fill in the location field and then call <%= @user.profile.location.upcase %> then it doesn't blow up since location is a string even it it's empty.

Is this the rails convention to have it this way? If so, then why? It's weird a bit since let's say there is a number_of_pets attr on the profile and then I try to call something like

<% if user.profile.number_of_pets.odd? %>
  <%= @user.profile.first_name %> has odd number of pets
<% end %>

then it blow's up since I can't call nil.odd?.

form as usual, so it will saved as empty string if not filled

<%= form_for @profile, url: user_profile_path do |f| %>
  <%= f.label :city %>
  <%= f.text_field :location, class: 'form-control' %>
  ......

Answer 1

The easiest work around is to use a gem like "strip_attributes" found here: https://github.com/rmm5t/strip_attributes

A custom workaround could be done by adding a before_save callback in your model that takes any values that are blank and sets them back to nil.

In your model for example:

before_save :my_nil_maker_method_lol

[...]

def my_nil_maker_method_lol
  if self.whatever_attribute.blank?
    self.whatever_attribute=nil
  end
end

Update:

Keeping blank fields from being saved could be done several ways such as described above or even deleting blank params in your controller before they hit the database.

The Rails way, when maintaining database integrity, is to always keep this logic inside your model. It makes it much easier to maintain and leaves much less room for surprises like if you were to modify the incoming parameters somewhere else.

As far as how it should be done in the model is really just a matter of what you as the developer expect to get for input. You can add a callback as shown above which maintains your db as you see fit or you can add a validates_presence_of validation that will return an error to the user if that field is left blank.

If you're asking whether you should be keeping empty strings from being inserted into the database at all, it is really up to you as the developer since there may be instances where you might want that information but in this case it sounds as though you're looking to restrict empty strings.