my @fields = qw(nachname vorname adresse ort);
my $cgi = CGI->new();
my %params = $cgi->Vars();

my $sql = 'INSERT INTO tabelle ('
  . join(', ', @fields)
  . ') VALUES ('
  . join(", ", map { $dbh->quote( $params{$_} ) } @fields )
  . ')';