Dan Ott

Today I Learned — November 21, 2014

Let the database do all of the heavy lifting for counting your ActiveRecord objects.

Record.pluck(:owner_id).each_with_object(Hash.new(0)) { |id, counts|
  counts[id] += 1
}

Sums up the number of records for a owner in Ruby. The same can be achieved via ActiveRecord.

Record.group(:owner_id).count