如何从mysql获取客户ID，然后将其存储在会话变量中以在另一个文件中使用会话变量来检索信息

Question

I am new to PHP. I've made a login page and a register page, and I want to store the customer id after successful login or registration on my session variable so that I can use a session variable later in my cart file to retrieve cart details of that customer.The customer id is autoincrementing on the table so I don't take the input from the customer for the customer id. here are the codes

login.php:

    <?php
session_start();
$db=mysqli_connect("localhost","root","Naruto97","musicgallery");

if (isset($_POST['login_btn'])){
    $email = mysqli_real_escape_string($db,$_POST['email']);
    $password = mysqli_real_escape_string($db,$_POST['password']);
    $password=md5($password);
    $sql="SELECT * FROM LoginCredentials WHERE email='$email' AND password='$password'";
    $result = mysqli_query($db,$sql);
    if(mysqli_num_rows($result)==1){
        $_SESSION['message']="You are now logged in";
        $_SESSION['email']=$email;
        //Want to store the customer in session variable here after successful login
        header("location:home.php");
    }
    else{
        $_SESSION['message']= "Email/Password combination Incorrect";
    }
}

   ?>

register.php:

     <?php
session_start();
$db=mysqli_connect("localhost","root","Naruto97","musicgallery");

if (isset($_POST['register_btn'])){

    $username = mysqli_real_escape_string($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){
        $password=md5($password);
        $sql = "INSERT INTO LoginCredentials(Username,email,password) VALUES('$username','$email','$password')";
        mysqli_query($db, $sql);
        $_SESSION['message']="You are now logged in";
        $_SESSION['email']=$email;
        //Want to store the customer_id here in the session variable after successful registration
        header("location:home.php");
    }else{
        $_SESSION['message']="The passwords do not match";

    }
}
   ?>

cart.php:

     <?php
       session_start();
       $db=mysqli_connect("localhost","root","Naruto97","musicgallery");
       if(isset($_POST["add_to_cart"])){
         if(isset($_SESSION['email'])){
           $album_name = mysqli_real_escape_string($db,$_POST['hidden_name']);
           $price = mysqli_real_escape_string($db,$_POST['hidden_price']);
           $quantity = mysqli_real_escape_string($db,$_POST['quantity']);
           //$customer_id= $_SESSION['customer_id'];
           $sql = "INSERT INTO cart(album_name,price,quantity,customer_id) VALUES('$album_name','$price','$quantity','$customer_id')";
          mysqli_query($db, $sql);
          echo "<script>alert('Added to cart')</script>";
          echo "<script>window.location('kpop.php')</script>";
          } 
          else
          {
             echo "<script>alert('Please Login')</script>";
             echo "<script>window.location('kpop.php')</script>";
          }
      }
     ?>

Answer 1

To get the last insertid in mysqli use:-

  $sql = "INSERT INTO cart(album_name,price,quantity,customer_id) VALUES('$album_name','$price','$quantity','$customer_id')";
      mysqli_query($db, $sql);


$_SESSION['customerId']=mysqli_insert_id($db);//gets the last inserted customerid from db

For any further reference you can check in this link .