# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 540
      def add_index_length(option_strings, column_names, options = {})
        if options.is_a?(Hash) && length = options[:length]
          case length
          when Hash
            column_names.each {|name| option_strings[name] += "(#{length[name]})" if length.has_key?(name)}
          when Fixnum
            column_names.each {|name| option_strings[name] += "(#{length})"}
          end
        end

        return option_strings
      end