clarion/db/migrate/20141105100827_create_propositions_for_existing_events.rb

class CreatePropositionsForExistingEvents < ActiveRecord::Migration[4.2]
  def up
    events = execute 'SELECT * FROM events'

    events.each do |event|
      execute "INSERT INTO propositions (proposer_id, proposition_accepting_id, proposition_accepting_type, proposable_id, proposable_type, status, created_at, updated_at)
                 VALUES (#{event['user_id']}, #{event['track_id']}, 'Track', #{event['id']}, 'Event', #{event['state']}, '#{event['created_at']}', '#{event['updated_at']}')"
    end
  end

  def down
    event_ids = execute('SELECT * FROM events').map { |event| event['id'] }
    execute "DELETE FROM propositions WHERE proposable_id IN (#{event_ids.join(', ')}) AND proposable_type = 'Event'"
  end
end