php的mysqli数据库连接的两种方法

<?php
$connect = mysqli_connect(‘localhost‘,‘root‘,‘‘,‘volunteer‘) or die(‘Unale to connect‘);
$sql = "select * from vol_msg";
$result = mysqli_query($connect,$sql);
while($row = mysqli_fetch_row($result)){
    echo $row[0];
}
?>

<?php
//创建对象并打开连接，最后一个参数是选择的数据库名称
$mysqli = new mysqli(‘localhost‘,‘root‘,‘‘,‘volunteer‘);
//检查连接是否成功
if (mysqli_connect_errno()){
    //注意mysqli_connect_error()新特性
    die(‘Unable to connect!‘). mysqli_connect_error();
}
$sql = "select * from vol_msg";
//执行sql语句，完全面向对象的
$result = $mysqli->query($sql);
while($row = $result->fetch_array()){
    echo $row[0];
}
?>