quoted_columns_for_index

# File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 755
        def quoted_columns_for_index(column_names, options = {})
          length = options[:length] if options.is_a?(Hash)

          quoted_column_names = case length
          when Hash
            column_names.map {|name| length[name] ? "#{quote_column_name(name)}(#{length[name]})" : quote_column_name(name) }
          when Fixnum
            column_names.map {|name| "#{quote_column_name(name)}(#{length})"}
          else
            column_names.map {|name| quote_column_name(name) }
          end
        end