my (@ffs) =("txtName", "txtCreated","txtDateren","txtOldname","txtDel");
my (%cols) = ("txtName"=>"Listname", "txtCreated"=>"DateCreated","txtDateren"=>"DateRenamed",
		"txtOldname"=>"OldListname","txtDel"=>"DateDeleted");

##</code><code>##

foreach(@ffs)
    {
      if($fd{$_} eq ""){
      	$updatestring = "$updatestring,[$cols{$_}] = NULL";
      }
      else{
      	$updatestring = "$updatestring,[$cols{$_}] = \'$fd{$_}\'";
      }
    }

##</code><code>##

my $sth = $db->prepare("UPDATE table SET $updatestring WHERE tbl.field = '$lname'");