In Rails 3 how should I manage a model column with limited choices

Question

In my Rails 3 application I have numerous models that have columns that have limited choices (IE a select box). It seems overkill in these cases to create another model and a relationship to the original model just to manage the choices.

One option I can think of is to just create a select box and have the choices in there, but that doesn't seem very DRY. Does anyone have a good suggestion how to handle this situation?

Thanks for looking.

Answer 1

You could create a constant in your model like so

# formatted as an array of options, option being an array of key, value
OPTIONS = [['Email', 'email'], ['Text', 'text'], ['Email and Text', 'both']]

validates_inclusion_of :field, :in => OPTIONS

Which can then be used to populate a select menu in a view very easily

Example using formtastic

<%= f.input :field, :as => :select, :collection => Model::OPTIONS %>

Answer 2

I usually do this with a constant list in the model.

class Model < ActiveRecord::Base
  PROPERTY_OPTIONS = ['Option One', 'Option Two', ...]
  validates_inclusion_of :property, :in => PROPERTY_OPTIONS
end

And in the view:

<%= f.select :property, Model::PROPERTY_OPTIONS %>

Answer 3

You can also use the enum_column plugin: https://github.com/electronick/enum_column

You can then render your select boxes in your views as follows:

<%= f.select :status, Model.columns_hash['status'].limit %>

(Where Model is an example model name, such as Book or Product, or whatever it is your application is really about.)