class DontAcceptNullToEnvironmentTheme < ActiveRecord::Migration def self.up Environment.all(:conditions => {:theme => nil}).each do |environment| environment.update_attribute(:theme, 'default') end change_column :environments, :theme, :string, :default => 'default', :null => false end def self.down change_column :environments, :theme, :string, :default => nil, :null => true Environment.all(:conditions => {:theme => 'default'}).each do |environment| environment.update_attribute(:theme, nil) end end end