Question

So I’ve a user model and a corresponding table (users) with fields: User_id, username, password etc.

But then I added invitation_limit to users table. Newly created users have invitation_limit, however the users created before the invitation_token migration was run don’t have the invitation_limit field.

How do I update the previously created users to include invitation_token field? Mind you I’m not talking about adding invitation_limit field to users table (i.e. migration), but rather updating already created users.

Thanks,

Answer 1

Seed data shouldn’t be put in a migration. Migrations are for creating structure, not adding data, and you’ll run into problems if you ever move the database.

You could write a rake task. If you create an instance method called something like “generate_invitation_token”, you can then write a rake task like this:

# lib/tasks/invitation_tokens.rake
namespace :seed do
  desc "generate invitation tokens for users that don't have one already"
  task :user_tokens => :environment do
    User.all(:conditions => {:invitation_token => nil}).each do |user|
      user.generate_invitation_token
    end
  end
end

You can then call the rake task from the commandline like this:

rake seed:user_tokens

This is a cleaner way to do it.

UPDATE

I’ve expanded this answer in a blog post called “Adding Columns and Default Data To Existing Models“.