Php 检查数据库中是否已存在用户名和电子邮件
我刚开始使用php,我尝试创建一个系统,如果您键入已有的用户名或密码,我会拒绝“创建帐户”。谢谢您,很抱歉我的英语不好。 我已经试过了。无效: 这是我的php:Php 检查数据库中是否已存在用户名和电子邮件,php,mysql,validation,email,Php,Mysql,Validation,Email,我刚开始使用php,我尝试创建一个系统,如果您键入已有的用户名或密码,我会拒绝“创建帐户”。谢谢您,很抱歉我的英语不好。 我已经试过了。无效: 这是我的php: 如果(mysqli_num_rows($res)>0)在这一行之前,您缺少了非常重要的一行if(mysqli_num_rows($res) 首先,session\u start()被调用两次。如果($password==$password2){ 您的代码还缺少一个;和一些}(用于正确关闭if条件) 现在解决方案: 在处理数据库查询的结果
如果(mysqli_num_rows($res)>0)在这一行之前,您缺少了非常重要的一行if(mysqli_num_rows($res)
首先,session\u start()
被调用两次。
如果($password==$password2){
您的代码还缺少一个
;
和一些}
(用于正确关闭if
条件)现在解决方案:
在处理数据库查询的结果之前,您需要连接到数据库并执行适当的SQL命令,然后才能得到所需的结果。您的代码缺少此进程。
在下面的代码中检查我的注释↓ 然后在更正的代码中再次检查
if ($password == $password2) {
session_start(); // remove this repeated call
$password = ($password);
$sql="select * from account_info where (username='$username' or email='$email')";
if (mysqli_num_rows($res) > 0) { // $res isn't defined
$row = mysqli_fetch_assoc($res);
if ($username==$row['username'])
{
$_SESSION['message'] = "Username je vec registrovan";
}
else($email==$row['email']){ // `else` doesn't work this way, use `elseif`
$_SESSION['message'] = "Email je vec registrovan" // ; missing
}
更正代码: 建议:
(关键是,您当前的代码容易受到SQL注入的攻击)
<?php
session_start();
$db = mysqli_connect("localhost", "root", "", "itsnikola");
if (isset($_POST['register_btn'])) {
$name = mysqli_real_escape_string($db, $_POST['name']);
$lastname = mysqli_real_escape_string($db, $_POST['lastname']);
$username = mysqli_real_escape_string($db, $_POST['username']);
$email = mysqli_real_escape_string($db, $_POST['email']);
$password = mysqli_real_escape_string($db, $_POST['password']);
$password2 = mysqli_real_escape_string($db, $_POST['password2']);
if ($password == $password2) {
$password = ($password);
$sql = "select * from account_info where (username='$username' or email='$email')";
$res = mysqli_query($db, $sql); // you were calling $res but it wasn't defined; this connects to the DB and executes SQL and then assigns the result
if (mysqli_num_rows($res) > 0) {
$row = mysqli_fetch_assoc($res);
if ($username == $row['username']) {
$_SESSION['message'] = "Username je vec registrovan";
} elseif ($email == $row['email']) { // changed `else` to `elseif` to include the condition, `else` doesn't accept conditional checks
$_SESSION['message'] = "Email je vec registrovan"; // added ;
} else {
$sql = "INSERT INTO users(name, lastname, username, email, password) VALUES('$name' , '$lastname' , '$username' , '$email' , '$password')";
mysqli_query($db, $sql);
$_SESSION['message'] = "Sada si ulogovan";
$_SESSION['message'] = $username;
header("location:login.php");
}
} // required to close `if (mysqli_num_rows($res) > 0)`
} // required to close the password checking condition
else {
$_SESSION['message'] = "Ne podudaraju se lozinke!";
}
}
?>
如果您能准确地解释什么是不起作用的,那会很有帮助——错误消息?没有插入数据库?未检测到重复?等
if ($password == $password2) {
session_start(); // remove this repeated call
$password = ($password);
$sql="select * from account_info where (username='$username' or email='$email')";
if (mysqli_num_rows($res) > 0) { // $res isn't defined
$row = mysqli_fetch_assoc($res);
if ($username==$row['username'])
{
$_SESSION['message'] = "Username je vec registrovan";
}
else($email==$row['email']){ // `else` doesn't work this way, use `elseif`
$_SESSION['message'] = "Email je vec registrovan" // ; missing
}
if (isset($_POST['register_btn'])) {
$name = mysqli_real_escape_string($db, $_POST['name']);
$lastname = mysqli_real_escape_string($db, $_POST['lastname']);
$username = mysqli_real_escape_string($db, $_POST['username']);
$email = mysqli_real_escape_string($db, $_POST['email']);
$password = mysqli_real_escape_string($db, $_POST['password']);
$password2 = mysqli_real_escape_string($db, $_POST['password2']);
if ($password == $password2) {
$password = ($password);
$sql = "SELECT * FROM users WHERE (username='$username' OR email='$email')";
$res = mysqli_query($db, $sql); // you were calling $res but it wasn't defined; this connects to the DB and executes SQL and then assigns the result
if (mysqli_num_rows($res) > 0) {
$row = mysqli_fetch_assoc($res);
if ($username == $row['username']) {
$_SESSION['message'] = "Username je vec registrovan";
} elseif ($email == $row['email']) { // changed `else` to `elseif` to include the condition, `else` doesn't accept conditional checks
$_SESSION['message'] = "Email je vec registrovan"; // added ;
}
} else {
$sql = "INSERT INTO users (name, lastname, username, email, password) VALUES ('$name', '$lastname', '$username', '$email', '$password')";
if (mysqli_query($db, $sql)) {
// New record inserted
$_SESSION['message'] = "Sada si ulogovan";
$_SESSION['message'] = $username;
header("location: login.php");
} else {
echo("Error: " . mysqli_error($db));
}
}
} // required to close the password checking condition
else {
$_SESSION['message'] = "Ne podudaraju se lozinke!";
}
}
<?php
session_start();
$db = mysqli_connect("localhost", "root", "", "itsnikola");
if (isset($_POST['register_btn'])) {
$name = mysqli_real_escape_string($db, $_POST['name']);
$lastname = mysqli_real_escape_string($db, $_POST['lastname']);
$username = mysqli_real_escape_string($db, $_POST['username']);
$email = mysqli_real_escape_string($db, $_POST['email']);
$password = mysqli_real_escape_string($db, $_POST['password']);
$password2 = mysqli_real_escape_string($db, $_POST['password2']);
if ($password == $password2) {
$password = ($password);
$sql = "select * from account_info where (username='$username' or email='$email')";
$res = mysqli_query($db, $sql); // you were calling $res but it wasn't defined; this connects to the DB and executes SQL and then assigns the result
if (mysqli_num_rows($res) > 0) {
$row = mysqli_fetch_assoc($res);
if ($username == $row['username']) {
$_SESSION['message'] = "Username je vec registrovan";
} elseif ($email == $row['email']) { // changed `else` to `elseif` to include the condition, `else` doesn't accept conditional checks
$_SESSION['message'] = "Email je vec registrovan"; // added ;
} else {
$sql = "INSERT INTO users(name, lastname, username, email, password) VALUES('$name' , '$lastname' , '$username' , '$email' , '$password')";
mysqli_query($db, $sql);
$_SESSION['message'] = "Sada si ulogovan";
$_SESSION['message'] = $username;
header("location:login.php");
}
} // required to close `if (mysqli_num_rows($res) > 0)`
} // required to close the password checking condition
else {
$_SESSION['message'] = "Ne podudaraju se lozinke!";
}
}
?>