player_shard_v1.rb

class PlayerShard < ActiveRecord::Base
  def self.with_date(date)
    current_table_name = self.table_name
    self.table_name = self.shard_table_name(date)
    create_shard(date)

    yield

  ensure
    self.table_name = current_table_name
  end
  
  def self.create_shard(date)
    connection.execute(<<-CREATE_SHARD)
      CREATE TABLE IF NOT EXISTS `player_shards_#{date.strftime("%Y%m%d")}` (
        `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
        `user_id` int(11) NOT NULL,
        
        -- other columns
        
        PRIMARY KEY (`id`),
        
        -- you'll probably want indexes too!
        KEY `index_player_sessions_on_user_id` (`user_id`)
        
      ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
    CREATE_SHARD
  end
end