# File lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 576
      def quoted_columns_for_index(column_names, options = {})
        option_strings = Hash[column_names.map {|name| [name, '']}]

        # add index length
        option_strings = add_index_length(option_strings, column_names, options)

        # add index sort order
        option_strings = add_index_sort_order(option_strings, column_names, options)

        column_names.map {|name| quote_column_name(name) + option_strings[name]}
      end