Rails Iterate over collection in model's class method without reloading query?

Question

I would like to iterate over a collection in a Model's class method. Unfortunately, the only way seems to be using all :

def self.do_something
  all.each do |question|
    #do stuff
  end
end

questions = Question.pick_random.load
User.all.each { |user| questions.do_something_for(user) }

The problem is : This load the questions every time the method is called... It's pretty slow, obviously. Is there any method to not reload the query ?

Answer 1

You could memoize the results:

def self.do_something
  @do_something ||= begin
    all.each do |question|
      #do stuff
    end
  end
end

Then, the query (and the computation) will only be performed the first time you call the method. The next time, it will just return @do_something