my $select = "select datensatz from kunden where kunde = ?";

my $con = "DBI:$db{type}:database=$db{name};host=$db{host};port=$db{port}";
my $dbh = DBI->connect($con, $db{user}, $db{pass}) or die DBI->errstr;
my $sth = $dbh->prepare($select) or die $dbh->errstr;

$sth->execute($kunde) or die $sth->errstr;