งง งง โค๊ด php ตัวนี้น่ะครับ ??????????????????...................

<?php 
if(!$dbconnect = mysql_connect('localhost', 'user', 'pass')) {
   echo "Connection failed to the host 'localhost'.";
   exit;
} // if
if (!mysql_select_db('test')) {
   echo "Cannot connect to database 'test'";
   exit;
} // if

$table_id = 'some_table';
$query = "SELECT * FROM $table_id";
$dbresult = mysql_query($query, $dbconnect);
// create a new XML document
$doc = new DomDocument('1.0');
// create root node
$root = $doc->createElement('root');
$root = $doc->appendChild($root);
// process one row at a time
while($row = mysql_fetch_assoc($dbresult)) {
  // add node for each row
  $occ = $doc->createElement($table_id);
  $occ = $root->appendChild($occ);
  // add a child node for each field
  foreach ($row as $fieldname => $fieldvalue) {
    $child = $doc->createElement($fieldname);
    $child = $occ->appendChild($child);
    $value = $doc->createTextNode($fieldvalue);
    $value = $child->appendChild($value);
  } // foreach
} // while
// get completed xml document
$xml_string = $doc->saveXML();
echo $xml_string;
?>