my $dbh = DBI->connect( "dbi:Oracle:$db_host", $db_user, $db_pass,
                     ) || die "Database connection not made: $DBI::errstr";

    $dbh->{RaiseError} = 0;
    $dbh->{PrintError} = 0;

my $sth = $dbh->prepare(q{
     INSERT into DGKTO_BASIS
     ( Feld1, Feld2, Feld3, Feld4 )
     ) values (
       ?, ?, TO_DATE(?,'YYYYMMDD'), ?
   }) || die "Can't prepare statement: $DBI::errstr";
...
# Hauptschleife
...
    if($sth->execute ($feld1, $feld2, $feld3, $feld4)){
   ...
   }