Practical method to implement shopping cart function using PHP MySQL technology

The shopping cart is a very important function in e-commerce websites. It allows users to easily add the items they want to buy to the shopping cart, and view and manage the items they want to buy at any time. Selected merchandise. This article will introduce how to use PHP and MySQL technology to implement the shopping cart function to make the website user experience smoother and more convenient.

1. Create a database

First, we need to create a database to store shopping cart-related information, including product information, user information, the number of products in the shopping cart, etc. We can create a database named shopping_cart, which contains the following table structure:

• Product table products: including product ID, name, price and other fields
• User tableusers: Including user ID, user name, password and other fields
• Shopping cart tablecart: Including shopping cart ID, user ID , product ID, quantity and other fields

2. Connect to the database

In PHP, we need to use MySQLi or PDO and other technologies to connect to the database. The following is a simple sample code to connect to the database:

<?php
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "shopping_cart";

$conn = new mysqli($servername, $username, $password, $dbname);

if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}
echo "Connection successful";
?>

3. Add items to the shopping cart

When the user clicks the "Add to Cart" button, we need to add the selected items to the shopping cart. The following is a simple sample code for adding items to the shopping cart:

<?php
session_start();

if(isset($_POST['product_id'])) {
    $product_id = $_POST['product_id'];
    $user_id = $_SESSION['user_id']; // Assume the user is logged in

    $sql = "INSERT INTO cart (user_id, product_id, quantity) VALUES ('$user_id', '$product_id', 1)";

    if ($conn->query($sql) === TRUE) {
        echo "The item has been successfully added to the shopping cart";
    } else {
        echo "Error: " . $sql . "<br>" . $conn->error;
    }
}
?>

4. Display the contents of the shopping cart

Users can view the selected items in the shopping cart at any time. The following is a simple sample code for displaying the contents of the shopping cart:

<?php
$user_id = $_SESSION['user_id'];

$sql = "SELECT products.product_id, products.name, products.price, cart.quantity
        FROM cart
        INNER JOIN products ON cart.product_id = products.product_id
        WHERE cart.user_id = '$user_id'";

$result = $conn->query($sql);

if ($result->num_rows > 0) {
    while($row = $result->fetch_assoc()) {
        echo "Product ID: " . $row["product_id"]. " - Product name: " . $row["name"]. " - Price: " . $row["price"]. " - Quantity: " . $row["quantity"]. "<br>";
    }
} else {
    echo "Shopping cart is empty";
}
?>

5. Update the shopping cart quantity

Users can modify the product quantity on the shopping cart page. The following is a simple sample code for updating the shopping cart quantity:

<?php
if(isset($_POST['cart_id']) && isset($_POST['new_quantity'])) {
    $cart_id = $_POST['cart_id'];
    $new_quantity = $_POST['new_quantity'];

    $sql = "UPDATE cart SET quantity = '$new_quantity' WHERE cart_id = '$cart_id'";

    if ($conn->query($sql) === TRUE) {
        echo "Shopping cart quantity has been updated";
    } else {
        echo "Error: " . $sql . "<br>" . $conn->error;
    }
}
?>

The above is a simple example of using PHP and MySQL technology to implement the shopping cart function. Developers can further improve and customize the function as needed to achieve better user experience and actual needs. I hope this article is helpful to you and I wish you a happy shopping!

The above is the detailed content of Practical method to implement shopping cart function using PHP MySQL technology. For more information, please follow other related articles on the PHP Chinese website!