What columns does an ActiveRecord model have?

Something that bugs me about using ActiveRecord models is that I have to look in schema.rb file to remember what columns a model has.

Enter…What Column!

This is a little plugin I bunged together on the (long) train journey home from Scotland on Rails.

What it does is put a comment block in all of your ActiveRecord models detailing what columns this model has. The beauty is that it changes every time you run rake db:migrate in development mode – so once it’s installed it will always be up to date. Your models will now look like this:

class User < ActiveRecord::Base
# === List of columns ===
#   id         : integer 
#   name       : string 
#   created_at : datetime 
#   updated_at : datetime 
# =======================

Source code here:



Install it like this:

script/plugin install git://github.com/thechrisoshow/what_column.git

After you’ve installed it run this rake task to create the initial comment blocks.

rake what_column:add

Every time you run rake db:migrate from then on the comment blocks will be updated.


If you get sick of What Column, and you want to uninstall it do this:

rake what:column:remove

Delete the plugin from the vendor/plugins/what_column directory


This file writes stuff into your model files, and it may destroy stuff. So make sure you use a source control system – you know, just in case.

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