sub duplicate_record {
   my ($name, $surename) = @_;
   my $is_duplicate = 0;
   my $html_title = 'Duplicate records have been found!';

   open (DBFILE, "dbfile.pdb") or die("Cannot open file for matching: $!");
   local $_;
   while (<DBFILE>) {
      my @pattern_check = split(/,/, $_); #spit line where you see comma (,) ($record)
      if ($name eq $pattern_check[0] and $surename eq $pattern_check[1]) { #check if duplicate is available
         print $cgi->start_html($html_title).
               $cgi->h1('Duplicate records:').
               $cgi->p("$name $surename $phone already exists.\nGo back and fill something else than that!").
               $cgi->end_html;
         $is_duplicate = 1;
         last;
      }
   }
   close (DBFILE);

   save_db() unless $is_duplicate;
}