/* connect to the database (works) */
$dbHandle = new PDO('sqlite:'.$CFG->baseroot.'/db/mmt.db3');

function db_query($query) {
	global $dbHandle;

        /* load the query (works) */
	$handle = $dbHandle->query($query);

	/* check to see if Fetch is necessary (works) */ 
	if (substr($query,0,6) <> 'UPDATE') {

		/* do the fetch (works) */	
		$qr = $handle->fetch();

	}

        /* fix that releases the lock (doesn't work) */
	$handle=null;

	return $qr;
}

/* run the select query (works) */
$user = db_query("SELECT first_name FROM user WHERE id = '5'");

/* do the if (works) */
if ($user['name'] == 'John') {

	/* run the update. (this does not work and throws an error) */
	db_query("UPDATE user SET last_name = 'Doe' WHERE first_name = 'John'");
}

/* connect to the database */
try{

	$dbHandle = new PDO('sqlite:'.'your_path_to_.db3_file');
	$dbHandle->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

}catch( PDOException $exception ){
	die($exception->getMessage());
}

function db_query($queryString) {
	global $dbHandle;

	$query = $dbHandle->query($queryString);

	$i = 0;
	foreach ($query as $query2) {
		$queryReturn[$i] = $query2;
		$i++;
	}

	return $queryReturn[0];
}

// call like
$qdb = db_query("Select * From table_name Where field_name = 'x'");
// returns always an array