php 检查电子邮件是否存在于 MySQL 数据库中
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check if email exists in MySQL database
提问by Erwin van Ekeren
I am using the following PHP code to store data in my MySQL database, everything works perfect but I would like to build in a check; if the email already exists in the database then redirect to another page. (I'm a rookie when it comes to PHP)
我正在使用以下 PHP 代码将数据存储在我的 MySQL 数据库中，一切正常，但我想建立一个支票；如果电子邮件已存在于数据库中，则重定向到另一个页面。（我是 PHP 菜鸟）
<?php
if(empty($_POST['name']))
{} else {
define('DB_NAME', 'dbname');
define('DB_USER', 'dbuser');
define('DB_PASSWORD', 'dbpass');
define('DB_HOST', 'host');
$link = mysql_connect(DB_HOST, DB_USER, DB_PASSWORD);
if (!$link) { die('could not connect: ' . mysql_error()); }
$db_selected = mysql_select_db(DB_NAME, $link);
if (!$db_selected) { die('can not use ' . DB_NAME . ': ' . mysql_error()); }
$sql="INSERT INTO game (name, lastname, company, email, time) VALUES
('".$_POST['name']."','".$_POST['lastname']."','".$_POST['company']."','".$_POST['email']."','".$_POST['time']."')";
if (!mysql_query($sql)) { die('Error: ' . mysql_error()); }
mysql_close();
}
?>
回答by Magictallguy
if(!filter_var($_POST['email'], FILTER_VALIDATE_EMAIL)) {
exit('Invalid email address'); // Use your own error handling ;)
}
$select = mysqli_query($connectionID, "SELECT `email` FROM `game` WHERE `email` = '".$_POST['email']."'") or exit(mysqli_error($connectionID));
if(mysqli_num_rows($select)) {
exit('This email is already being used');
}
Stick that in abovethe insert query
将其粘贴在插入查询上方
回答by au_stan
First, to your question. The most simple is to use the header()function to redirect to a page.
首先，针对你的问题。最简单的就是使用header()函数重定向到一个页面。
if ( !$email) {
header('Location: http://example.com/new_page.html' );
} else {
// Continue with code
}
Secondly, there is a whole lot of issues going on in that code. For example:
其次，该代码中存在很多问题。例如：
- Use PDO
- parameterize your query
- Your control statement should probably look like
if(!empty($_POST['name'])) {
- 使用 PDO
- 参数化您的查询
- 您的控制语句可能看起来像
if(!empty($_POST['name'])) {
