Axon Flux // A Ruby on Rails Blog

ActiveRecord Table Transform (or, how to write to the db 27,000 times in 24 seconds instead of 9 minutes)

I implemented my new scheme and running time went from 9 minutes to 24 SECONDS. I liked this approach so much I decided to generalize it as ActiveRecord::Base.transform. Sample usage:
# if users don't have names, give them a random one
NAMES = ['Adam', 'Ethan', 'Patrick']
User.transform(:name, :conditions => 'name is null').each do |i|
  i.name = NAMES[rand * NAMES.length]
end

Really interesting use of temp tables here.