my @fields = qw(fornavn efternavn cpr adresse zip city tjenestested);

my $cgi = new CGI;

# apply validation/error checking as needed
# in this case, if no param is found, undef is default
my @params = map { $cgi->param($_) || undef } @fields;

# connect to database . . .

my $sth = $dbh->prepare(
   'INSERT into people(' .
   join(',', @fields), ') values(' .
   join(',', map { '?' } @fields), ')'
) or die $dbh->errstr;

$sth->execute(@params) or die $dbh->errstr;