mysql_connect (PHP 4, PHP 5)
mysql_connect — Open a connection to a MySQL Server
Warning This extension is deprecated as of PHP 5.5.0, and will be removed in the future. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:


mysqli_connect()
PDO::__construct()

http://php.net/manual/en/function.mysql-connect.php

在PHP5.5.0中被抛弃，在将来的版本会彻底移除！

This extension is deprecated as of PHP 5.5.0,
整个mysql扩展在PHP5.5中都已经被抛弃，不推荐使用了。

 robertpas550 at hotmail dot com ¶
3 years ago
New users are advised to use MySQL Improved mysqli_ functions rather than the older [replaced] mysql_ functions where applicable and subject the appropriate latest stable versions of Apache, php and MySQL, etc.

所有的mysql扩展页面都挂上了醒目的红框框：
Warning
This extension is deprecated as of PHP 5.5.0, and will be removed in the future. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:

    mysqli_affected_rows()
    PDOStatement::rowCount()

我们参考书上是讲用mysqli，老师课上讲用PDO

mysqli也是物件导向的php库。
而MySQL仅仅是一对函数，虽然c语言里面也是这些函数。

刚开始用MySQL的时候我很不习惯，因为是字符控制台界面的。但现在我倒是觉得比Microsoft access好太多了。

mysqli在国内的某本书上介绍过。

其实MySQLi库我只用过一次
2010.7那次