这两种MySQL连接方法有什么区别[关闭]

Question

I'm learning PHP. I've seen these two approaches to connecting to a MySQL database.

Could someone explain what's the difference between them, and why the second approach doesn't work in a standard form submission (is there a syntax error I have missed)?

Approach 1 (works):

$mysqli = new mysqli("$mysql_server", "$mysql_user", "$mysql_pw", "$mysql_db");
if ($mysqli->connect_errno) {
    echo "Failed to connect to MySQL: (" . $mysqli->connect_errno . ") " . $mysqli->connect_error;
}

Approach 2 (throws a server error):

$link = mysqli_connect("$mysql_server", "$mysql_user", "$mysql_pw", "$mysql_db");
if (!$link) {
    die('Could not connect: ' . mysql_error());
}

Answer 1

Approach 1 is the object oriented approach. Approach 2 is the procedural approach.