/** Makes the default connection. 
	@param PntDbQueryHandler $qh The QueryHandler that will make the connection,
	*	or null if an arbitrary instance of QueryHandler may be used.
	* @param boolean $makeDefault Wheather to make the connection the default
	* 	*/
	function makeConnection($qh=null, $makeDefault=true) {
		if (!$qh) $qh = new QueryHandler();
		$qh->setConnection($this);
		$qh->connect(); //sets $this->dbSource
		if ($this->dbSource === false) return;
		
		//connection succeeded
		if ($makeDefault)
			DatabaseConnection::defaultConnection($this);
	}