php - $db = new DB() 混淆

Question

请解释一下这是什么意思

$db = new DB(DB_DRIVER, DB_HOSTNAME, DB_USERNAME, DB_PASSWORD, DB_DATABASE);

它给了我一个错误

"Error: Could not load database file mysql!"

文件内容

define('DB_DRIVER', 'mysql');
define('DB_HOSTNAME', 'localhost');
define('DB_USERNAME', 'XXX');
define('DB_PASSWORD', 'XXX');
define('DB_DATABASE', 'XXXX');

数据库类构造函数

public function __construct($driver, $hostname, $username, $password, $database) {

        if (file_exists(DIR_DATABASE . $driver . '.php')) {

            require_once(DIR_DATABASE . $driver . '.php');

        } else {

            exit('Error: Could not load database file ' . $driver . '!');

        }



        $this->driver = new $driver($hostname, $username, $password, $database);

    }

Answer 1

您没有 mysql 数据库的驱动程序，请检查 DIR_DATABASE 文件夹中是否存在 mysql.php 文件。