php未知数据库？答案

【问题标题】：Php unknown database?php未知数据库？
【发布时间】：2018-03-21 06:56:59
【问题描述】：

我的 PHP 文档有问题。该项目是制作一个有效的登录/注册页面错误信息 -

Warning: mysqli_connect(): (HY000/1049): Unknown database 'registration' in 
C:\xampp\htdocs\registration\server.php on line 11

文件的拼写正确。此外，它不记得注册（我认为这与“未知数据库”问题有关？）

server.php 代码-

<?php 
	session_start();

	// variable declaration
	$username = "";
	$email    = "";
	$errors = array(); 
	$_SESSION['success'] = "";

	// connect to database
	$db = mysqli_connect('localhost', 'root', '', 'registration');

	// REGISTER USER
	if (isset($_POST['reg_user'])) {
		// receive all input values from the form
		$username = mysqli_real_escape_string($db, $_POST['username']);
		$email = mysqli_real_escape_string($db, $_POST['email']);
		$password_1 = mysqli_real_escape_string($db, $_POST['password_1']);
		$password_2 = mysqli_real_escape_string($db, $_POST['password_2']);

		// form validation: ensure that the form is correctly filled
		if (empty($username)) { array_push($errors, "Username is required"); }
		if (empty($email)) { array_push($errors, "Email is required"); }
		if (empty($password_1)) { array_push($errors, "Password is required"); }

		if ($password_1 != $password_2) {
			array_push($errors, "The two passwords do not match");
		}

		// register user if there are no errors in the form
		if (count($errors) == 0) {
			$password = md5($password_1);//encrypt the password before saving in the database
			$query = "INSERT INTO users (username, email, password) 
					  VALUES('$username', '$email', '$password')";
			mysqli_query($db, $query);

			$_SESSION['username'] = $username;
			$_SESSION['success'] = "You are now logged in";
			header('location: index.php');
		}

	}

	// ... 

	// LOGIN USER
	if (isset($_POST['login_user'])) {
		$username = mysqli_real_escape_string($db, $_POST['username']);
		$password = mysqli_real_escape_string($db, $_POST['password']);

		if (empty($username)) {
			array_push($errors, "Username is required");
		}
		if (empty($password)) {
			array_push($errors, "Password is required");
		}

		if (count($errors) == 0) {
			$password = md5($password);
			$query = "SELECT * FROM users WHERE username='$username' AND password='$password'";
			$results = mysqli_query($db, $query);

			if (mysqli_num_rows($results) == 1) {
				$_SESSION['username'] = $username;
				$_SESSION['success'] = "You are now logged in";
				header('location: index.php');
			}else {
				array_push($errors, "Wrong username/password combination");
			}
		}
	}

?>

文件树

xampp--
htdocs--
注册--
errors.php、index.php、login.php、register.php、server.php、style.css

【问题讨论】：

嗯，是否有一个名为registration的数据库？

标签： php database login server xampp

【解决方案1】：

您可能还没有使用“users”表创建名为“registration”的数据库？当你在本地主机上时，你可能有 PHPMyAdmin，它可以帮助你做到这一点。

【讨论】：

【解决方案2】：

 private $dbName = "forgot_pass_identity";

注意：输入正确的数据库名称

【讨论】：