mysqli执行mysql事务的有关问题

<br />
	public static function exec_sql_tran($arr_sql){<br />
		$result=true;<br />
		$con = new MySQLi(DBHOST,DB_USER,DB_PASSWD,DB_NAME);<br />
		$con->autocommit(FALSE);<br />
	 	foreach($arr_sql as $key=>$sql){<br />
			if (!$con->query($sql)) {<br />
				echo $con->error."<br>/";<br />
				$resulf=false;<br />
				$con->rollback();<br />
                                break;<br />
			}<br />
		}<br />
		print_r($result);<br />
		if($result){<br />
			$con->commit();<br />
		}<br />
		else{<br />
			$con->rollback();<br />
		}<br />
		$con->close();<br />
	}<br />