我的 PHP 到 mysql 中的数据冗余问题

Data redundancy problem in my PHP to mysql

任何人都可以查看我的 PHP 代码?如何修复 PHP 到 mysql 中的数据冗余?我不想将相同的数据存储到我的数据库中。谢谢

<?php

    $email = "";
    $passwords   = "";
    $firstname   = "";
    $lastname   = "";
    $errors = array(); 

    $db = mysqli_connect('localhost', 'root', '', 'wdt_assignment');


    if (isset($_POST['email'])) {
 
    $email = mysqli_real_escape_string($db, $_POST['email']);
    $password = mysqli_real_escape_string($db, $_POST['password']);
    $firstname = mysqli_real_escape_string($db, $_POST['firstname']);
    $lastname = mysqli_real_escape_string($db, $_POST['lastname']);

    if (empty($email)) { array_push($errors, "email is required"); }
    if (empty($password)) { array_push($errors, "password is required"); }
    if (empty($firstname)) { array_push($errors, "firstname is required"); }
    if (empty($lastname)) { array_push($errors, "lastname is required"); }
    }


    $user_check_query = "SELECT * FROM customer WHERE email='$Email' OR password='$Password' LIMIT 1";
    $result = mysqli_query($db, $user_check_query);
    $user = mysqli_fetch_assoc($result);

    if ($user) { // if user exists
    if ($user['email'] === $Email) {
      array_push($errors, "email already exists");
    }

    if ($user['password'] === $Password) {
      array_push($errors, "password already exists");
    }
  }
    if (count($errors) == 0) {
 
      $query = "INSERT INTO customer (email, password, firstname, lastname) 
                VALUES('$email', '$password', '$firstname','$lastname')";
      mysqli_query($db, $query);
      $_SESSION['email'] = $email;
      $_SESSION['success'] = "You are now logged in";
  }
?>

我建议你不要告诉用户这个密码已经存在于数据库中。我附上验证邮件是否存在的代码。

<?php

$email = "";
$passwords   = "";
$firstname   = "";
$lastname   = "";

$errors = array();

$db = mysqli_connect('localhost', 'root', '', 'wdt_assignment');

if (isset($_POST['email']))
{
    $email = mysqli_real_escape_string($db, $_POST['email']);
    $password = mysqli_real_escape_string($db, $_POST['password']);
    $firstname = mysqli_real_escape_string($db, $_POST['firstname']);
    $lastname = mysqli_real_escape_string($db, $_POST['lastname']);

    if (empty($email)) { array_push($errors, "email is required"); }
    if (empty($password)) { array_push($errors, "password is required"); }
    if (empty($firstname)) { array_push($errors, "firstname is required"); }
    if (empty($lastname)) { array_push($errors, "lastname is required"); }

    if (count($errors) == 0)
    {
        $user_check_query = "SELECT * FROM customer WHERE email='$Email' OR password='$Password' LIMIT 1";
        $result = mysqli_query($db, $user_check_query);
        $affected_rows = mysqli_affected_rows($db);

        if ($affected_rows > 0)
        {
            array_push($errors, "email already exists");
        }
        else
        {
            $query = "INSERT INTO customer (email, password, firstname, lastname) 
            VALUES('$email', '$password', '$firstname','$lastname')";
            mysqli_query($db, $query);
            $_SESSION['email'] = $email;
            $_SESSION['success'] = "You are now logged in";
        }
    }
}
?>