关于php连接mysql与ODBC方式访问mysql的差异

方法1：用php连接mysql
$conn = mysql_connect("localhost","root","pwd");
mysql_select_db("dbname",$conn);
方法2：用ODBC方式连接mysql
$conn = ADONewConnection('mysql');
$conn->Connet("localhost","root","pwd","dbname");请问大虾们 这两种方法的优劣是怎样的？能给个详细点的解释么？ 谢谢了...