# File lib/innodb/field.rb, line 63
  def value_by_length(cursor, field_length)
    if @data_type.respond_to?(:read)
      cursor.name(@data_type.name) { @data_type.read(cursor) }
    elsif @data_type.respond_to?(:value)
      @data_type.value(read(cursor, field_length))
    else
      read(cursor, field_length)
    end
  end