ActiveRecord MySQL Partitions

 class ActiveRecord::ConnectionAdapters::MysqlAdapter
   def create_partitioned_table(table_name, &block)
     partition_sql = <<-sql
        ENGINE=InnoDB AUTO_INCREMENT=610925 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci
        partition by range (to_days(created_at))
        (
          partition p_0 values LESS THAN (to_days('2000-01-01')),
     sql

     partitions = (-4..4).collect do |i|
       "partition p_#{(Time.zone.now+i.days).strftime("%Y%m%d") } values LESS THAN (to_days('#{(Time.zone.now+i.days).to_mysql_format}'))"
     end

     partition_sql << partitions.join(",\n") << ');'
     options = {:options => partition_sql}
     create_table(table_name, options, &block)
   end

   def native_database_types
     NATIVE_DATABASE_TYPES[:auto] = "int(11) NOT NULL auto_increment".freeze
     NATIVE_DATABASE_TYPES
   end

 end

class ActiveRecord::ConnectionAdapters::TableDefinition
  original_to_sql = self.instance_method(:to_sql)

  def composite_primary_key *args
    @columns << CompositeKeyColumn.new(*args)
  end

  define_method(:to_sql) do
    composite_key_count = @columns.count {|column| column.is_a? CompositeKeyColumn}

    if composite_key_count > 0
      @columns.each do |column|
        column.type = :auto if column.sql_type.include?('PRIMARY KEY')
      end
    end

    original_to_sql.bind(self).call
  end
end