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PHP and MySQL Shopping Cart Tutorial – Using SESSIONS To Store Cart Data

shopping-cart-in-php-sessions

Previously, we learned how to build a Shopping Cart with PHP & MySQL where we used a database to store cart items. Today, we will learn another version of it. We will use PHP session variables to store cart items.

This tutorial have the following contents:

1.0 Overview
2.0 Tutorial Output Preview
3.0 File Structure

4.0 Prepare the database
4.1 Database design
4.2 Create a database
4.3 Create “products” table
4.4 Create “categories” table
4.5 Download sample data and images
4.6 Extract and import data
4.7 Database connection file

5.0 Create the layout files
5.1 Create header layout file
5.2 Create footer layout file
5.3 Create navigation layout file
5.4 Create Custom CSS file

6.0 Display Products
6.1 Create product page
6.2 Include PHP Classes
6.3 Create “product” object
6.4 Create “product image” object
6.5 Connect to the database
6.6 Initialize action and pagination
6.7 Display messages based on action
6.8 Request data from the database
6.9 Add “read” and “count” methods
6.10 Template to display products
6.11 Add “readFirst()” method
6.12 Make “add to cart” button work
6.13 Create pagination file

7.0 How to add to cart?
7.1 Create add_to_cart.php
7.2 Create cart page
7.3 Display message based on action
7.4 Display cart items
7.5 Read products by IDs

8.0 How to update cart?
8.1 Update cart quantity with JavaScript
8.2 PHP script to update cart
8.3 How to remove product on cart?
8.4 Create the checkout page
8.5 Create place_order.php

9.0 How to make the product page?
9.1 Create product.php
9.2 Read product details
9.3 Read one product method
9.4 Display product thumbnails
9.5 Read images related to product
9.6 Display product image
9.7 Make image hover work
9.8 Display product details
9.9 Render ‘Cart’ button

10.0 What people say about this code?
11.0 How to run the source code?

12.0 Download LEVEL 1 source code
13.0 Download LEVEL 2 source code

14.0 PHP Shopping Cart Module
15.0 PHP Shopping Cart System

16.0 What’s Next?
17.0 Related Tutorials
18.0 Some Notes

Before we start, we want to let you know that your feedback is important to us!

If there's a section in this tutorial that is confusing or hard to understand, we consider it as a problem. Please let us know. We will solve this problem within 24 hours.

Send a detailed description of the problem to my email to mike@codeofaninja.com today. Use "codeofaninja.com improvement" as the subject of your email. Thank you!

1.0 Overview

1.1 Introduction

If you want to build your own online shopping cart from scratch, we have good news for you!

This post can help you get it done because we will build a simple shopping cart script today.

We will use PHP, MySQL and PHP sessions to complete this task.

A lot of people use a ready-made software for this.

But for coders like us, it is important to learn and experience how to do it. We can create more features like making the system more secured, add some unique functionality and more.

Your imagination can be the only limit.

1.2 Is this code for you?

The source codes in this page is NOT for you if:

  • You are already an expert in PHP & MySQL programming.
  • You have a lot of time to code a shopping cart system from scratch.
  • You are not that interested in learning PHP & MySQL programming.

But, this SOURCE CODE is FOR YOU if:

  • You want to SAVE huge amount of development time.
  • You want to develop your own shopping cart system from scratch.
  • You determined to learn how to make a web application in PHP & MySQL.

But if you are an expert in PHP & MySQL programming and would like to take a look at our code, please do so! We’d love to hear your response and great insights! The comments section below is always open for anyone with questions and suggestions.

1.3 How to use this tutorial?

This tutorial is already working. You can proceed to the instructions below.

But we are recording a video demo about how to use this tutorial.

It is coming soon! Please subscribe here so you will be updated.

2.0 Tutorial Output Preview

Below are some screenshots of our script’s output. You can click an image to view the larger version of it. Use the left and right arrow to navigate through the screenshots.

Please note that the following images are just output previews. New features might be added already the time you are reading this.

2.1 LEVEL 1 Source Code Output


2.2 LEVEL 2 Source Code Output


The LEVEL 2 source code output proves that you can add and customize more features. It will be easier and faster if you will learn by following our tutorial below.

Downloading our source codes is your huge advantage as well.

If you need more features like product variations, admin features and user login, see our PHP Shopping Cart Module and PHP Shopping Cart System.

For now, let’s proceed to the step by step tutorial of our LEVEL 1 source code. Enjoy!

3.0 File Structure

The following folders and files are included in the source code. It will have more meaning if you will see the code inside the folders and files.

├─ config/
├─── database.php
├─ dev/
├─── shop_cart_sessions_1.sql
├─── readme.txt
├─ images/
├─ libs/
├─── css/
├────── bootstrap/
├─── js/
├────── jquery.js
├─ objects/
├─── product_image.php
├─── product.php
├─ uploads/
├─── images/
├─ .htaccess
├─ add_to_cart.php
├─ cart.php
├─ checkout.php
├─ layout_foot.php
├─ layout_head.php
├─ navigation.php
├─ paging.php
├─ place_order.php
├─ product.php
├─ products.php
├─ read_products_template.php
├─ remove_from_cart.php
├─ update_quantity.php

4.0 Prepare the database

4.1 Database Design

Our database name will be called “shop_cart_sessions_1”, and we will have two (2) tables.
php shopping cart tutorial database design

4.2 Create a database

  • Open your PhpMyAdmin (http://localhost/phpmyadmin)
  • Create a new database.
  • Put “shop_cart_sessions_1” as database name.
  • Click “Create” button.

4.3 Create “products” table

In this section, we will create the “products” table (using PhpMyAdmin) on the database we just created. This table will hold products record.

Here’s how to run an SQL statement using PhpMyAdmin.

  • Click “php_oop_crud_level_1” database.
  • Click “SQL” tab.
  • Copy the SQL statement below and paste it in the text area.
  • Click the “Go” button.
CREATE TABLE IF NOT EXISTS `products` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(512) NOT NULL,
  `description` text NOT NULL,
  `price` decimal(10,2) NOT NULL,
  `created` datetime NOT NULL,
  `modified` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM  DEFAULT CHARSET=latin1 COMMENT='products that can be added to cart' AUTO_INCREMENT=41 ;

4.4 Create “categories” table

This table will hold images related to product.

Run the following SQL statement using your PhpMyAdmin.

CREATE TABLE IF NOT EXISTS `product_images` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `product_id` int(11) NOT NULL,
  `name` varchar(512) NOT NULL,
  `created` datetime NOT NULL,
  `modified` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM  DEFAULT CHARSET=utf8 COMMENT='image files related to a product' AUTO_INCREMENT=105 ;

4.5 Download sample data and images

The products and product_images table will not fully work without the sample data and related image files.

You’ll have to download the SQL and image files. Use the download button below.

What will you get? A ZIP file with shop_cart_sessions_1.sql and 28 image files inside (1.30 MB).

4.6 Extract and import data

Once downloaded, please extract the files.

Import the SQL file using PhpMyAdmin.

Put the image files in “php-shopping-cart-using-sessions-level-1/uploads/images/” directory. That directory does not exist yet. We need to create it now.

  • Create “php-shopping-cart-using-sessions-level-1” folder and open it. This is our project’s main folder.
  • Create “uploads” folder and open it.
  • Create “images” folder and open it.
  • Copy and paste the images on this directory.

4.7 Database connection file

This file will be used to get connection to the database.

  • Open “php-shopping-cart-using-sessions-level-1” folder.
  • Create “config” folder and open it.
  • Create “database.php” file and open it.
  • Place the following code.
<?php
// used to get mysql database connection
class Database{

	// specify your own database credentials
	private $host = "localhost";
	private $db_name = "shop_cart_sessions_1";
	private $username = "root";
	private $password = "";
	public $conn;

	// get the database connection
	public function getConnection(){

		$this->conn = null;

		try{
			$this->conn = new PDO("mysql:host=" . $this->host . ";dbname=" . $this->db_name, $this->username, $this->password);
		}catch(PDOException $exception){
			echo "Connection error: " . $exception->getMessage();
		}

		return $this->conn;
	}

}
?>

5.0 Create the layout files

5.1 Create header layout file

This “layout_header.php” file will be included at the beginning of the PHP files that will need it. This way, we won’t have to write the same header codes every time.

We use the Bootstrap framework to make our project look good. If you’re not yet familiar with you, please learn our Bootstrap tutorial here.

Bootstrap CSS asset will be included inside the head tags.

  • Open “php-shopping-cart-using-sessions-level-1” folder.
  • Create “layout_header.php” file.
  • Place the following code.
<?php
$_SESSION['cart']=isset($_SESSION['cart']) ? $_SESSION['cart'] : array();
?>
<!DOCTYPE html>
<html lang="en">
<head>

    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1">

    <title><?php echo isset($page_title) ? $page_title : "The Code of a Ninja"; ?></title>

    <!-- Latest compiled and minified Bootstrap CSS -->
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" />
  
    <!-- our custom CSS -->
    <link rel="stylesheet" href="libs/css/custom.css" />

</head>
<body>

	<?php include 'navigation.php'; ?>

    <!-- container -->
    <div class="container">
        <div class="row">

        <div class="col-md-12">
            <div class="page-header">
                <h1><?php echo isset($page_title) ? $page_title : "The Code of a Ninja"; ?></h1>
            </div>
        </div>

5.2 Create footer layout file

This “layout_footer.php” will be included at the end of the PHP files that will needs it. This way, we won’t have to write the same footer codes every time.

The assets used in this file are:

Let’s go on and create the footer layout file.

  • Open “php-shopping-cart-using-sessions-level-1” folder.
  • Create “layout_footer.php” file.
  • Place the following code.
		</div>
		<!-- /row -->

	</div>
	<!-- /container -->

<!-- jQuery (necessary for Bootstrap's JavaScript plugins) -->
<script src="https://code.jquery.com/jquery-3.2.1.min.js"></script>
 
<!-- Latest compiled and minified Bootstrap JavaScript -->
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>

</body>
</html>

5.3 Create navigation layout file

This file will render the “Products” and “Cart” links that the user can click.

  • Open “php-shopping-cart-using-sessions-level-1” folder.
  • Create “navigation.php” file.
  • Place the following code.
<!-- navbar -->
<div class="navbar navbar-default navbar-static-top" role="navigation">
	<div class="container">

		<div class="navbar-header">
			<button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-collapse">
			<span class="sr-only">Toggle navigation</span>
			<span class="icon-bar"></span>
			<span class="icon-bar"></span>
			<span class="icon-bar"></span>
			</button>
			<a class="navbar-brand" href="products.php">XYZ Webstore</a>
		</div>

		<div class="navbar-collapse collapse">
			<ul class="nav navbar-nav">

				<!-- highlight if $page_title has 'Products' word. -->
				<li <?php echo $page_title=="Products" ? "class='active'" : ""; ?>>
					<a href="products.php" class="dropdown-toggle">Products</a>
				</li>

				<li <?php echo $page_title=="Cart" ? "class='active'" : ""; ?> >
					<a href="cart.php">
						<?php
						// count products in cart
						$cart_count=count($_SESSION['cart']);
						?>
						Cart <span class="badge" id="comparison-count"><?php echo $cart_count; ?></span>
					</a>
				</li>
			</ul>

		</div><!--/.nav-collapse -->

	</div>
</div>
<!-- /navbar -->

5.4 Create custom CSS file

This custom.css file is where our custom styles are located.

  • Open “php-shopping-cart-using-sessions-level-1” folder.
  • Open “libs” folder.
  • Open “css” folder.
  • Create “custom.css” file.
  • Place the following code.
.text-align-center{ text-align:center; }
.f-w-b{ font-weight:bold; }
.display-none{ display:none; }

.w-5-pct{ width:5%; }
.w-10-pct{ width:10%; }
.w-15-pct{ width:15%; }
.w-20-pct{ width:20%; }
.w-25-pct{ width:25%; }
.w-30-pct{ width:30%; }
.w-35-pct{ width:35%; }
.w-40-pct{ width:40%; }
.w-45-pct{ width:45%; }
.w-50-pct{ width:50%; }
.w-55-pct{ width:55%; }
.w-60-pct{ width:60%; }
.w-65-pct{ width:65%; }
.w-70-pct{ width:70%; }
.w-75-pct{ width:75%; }
.w-80-pct{ width:80%; }
.w-85-pct{ width:85%; }
.w-90-pct{ width:90%; }
.w-95-pct{ width:95%; }
.w-100-pct{ width:100%; }

.m-t-0px{ margin-top:0px; }
.m-b-10px{ margin-bottom:10px; }
.m-b-20px{ margin-bottom:20px; }
.m-b-30px{ margin-bottom:30px; }
.m-b-40px{ margin-bottom:40px; }

.stock-text {
    font-weight: bold;
    color: #008a00;
}

.stock-text-red{
    font-weight:bold;
    color:#b12704;
}

.product-detail {
    font-weight: bold;
    margin: 0 0 5px 0;
}

.blueimp-gallery>.prev, .blueimp-gallery>.next{ border:none; }

.update-quantity-form {
    width: 150px;
    float: left;
    margin: 0 10px 0 0;
}

.cart-row {
    border-bottom: thin solid #f1f1f1;
    overflow: hidden;
    width: 100%;
    padding: 20px 0 20px 0;
}

.product-link{
    color:#000000;
}

.product-link:hover{
    color:#000000;
    text-decoration:none;
}

.product-img-thumb {
    margin: 0 0 10px 0;
    width: 100%;
    cursor: pointer;
}

6.0 Display Products

6.1 Create products.php

Now we are going to start displaying products from the database. Create products.php with the following basic code.

<?php
// start session
session_start();

// set page title
$page_title="Products";

// page header html
include 'layout_head.php';

// contents will be here 

// layout footer code
include 'layout_foot.php';
?>

6.2 Include PHP Classes

Put the following code after “session_start();” code of the previous section.

// connect to database
include 'config/database.php';

// include objects
include_once "objects/product.php";
include_once "objects/product_image.php";

6.3 Create “product” object file

Create “objects” folder. Inside it, create product.php file with the following code.

<?php
// 'product' object
class Product{

	// database connection and table name
	private $conn;
	private $table_name="products";

	// object properties
	public $id;
	public $name;
	public $price;
	public $description;
	public $category_id;
	public $category_name;
	public $timestamp;

	// constructor
	public function __construct($db){
		$this->conn = $db;
	}
}

6.4 Create “product image” object file

Create product_image.php file inside “objects” folder.

<?php
// 'product image' object
class ProductImage{

	// database connection and table name
	private $conn;
	private $table_name = "product_images";

	// object properties
	public $id;
	public $product_id;
	public $name;
	public $timestamp;

	// constructor
	public function __construct($db){
		$this->conn = $db;
	}
}

6.5 Connect to the database

Put the following code after the code on the previous section.

// get database connection
$database = new Database();
$db = $database->getConnection();

// initialize objects
$product = new Product($db);
$product_image = new ProductImage($db);

6.6 Initialize action and pagination

Put the following code after the code on the previous section.

// to prevent undefined index notice
$action = isset($_GET['action']) ? $_GET['action'] : "";

// for pagination purposes
$page = isset($_GET['page']) ? $_GET['page'] : 1; // page is the current page, if there's nothing set, default is page 1
$records_per_page = 6; // set records or rows of data per page
$from_record_num = ($records_per_page * $page) - $records_per_page; // calculate for the query LIMIT clause

6.7 Display messages based on action

We’ll display messages basedon given action. Put the following code after “include ‘layout_head.php’;” code.

]
echo "<div class='col-md-12'>";
	if($action=='added'){
		echo "<div class='alert alert-info'>";
			echo "Product was added to your cart!";
		echo "</div>";
	}

	if($action=='exists'){
		echo "<div class='alert alert-info'>";
			echo "Product already exists in your cart!";
		echo "</div>";
	}
echo "</div>";

6.8 Request data from the database

Request data from the database. Put the following code after the code on the previous section.

// read all products in the database
$stmt=$product->read($from_record_num, $records_per_page);

// count number of retrieved products
$num = $stmt->rowCount();

// if products retrieved were more than zero
if($num>0){
	// needed for paging
	$page_url="products.php?";
	$total_rows=$product->count();

	// show products
	include_once "read_products_template.php";
}

// tell the user if there's no products in the database
else{
	echo "<div class='col-md-12'>";
    	echo "<div class='alert alert-danger'>No products found.</div>";
	echo "</div>";
}

6.9 Add “read” and “count” methods

The previous section will not work without the following code inside “objects/product.php” object file.

// read all products
function read($from_record_num, $records_per_page){

	// select all products query
	$query = "SELECT
				id, name, description, price 
			FROM
				" . $this->table_name . "
			ORDER BY
				created DESC
			LIMIT
				?, ?";

	// prepare query statement
	$stmt = $this->conn->prepare( $query );

	// bind limit clause variables
	$stmt->bindParam(1, $from_record_num, PDO::PARAM_INT);
	$stmt->bindParam(2, $records_per_page, PDO::PARAM_INT);

	// execute query
	$stmt->execute();

	// return values
	return $stmt;
}

// used for paging products
public function count(){

	// query to count all product records
	$query = "SELECT count(*) FROM " . $this->table_name;

	// prepare query statement
	$stmt = $this->conn->prepare( $query );

	// execute query
	$stmt->execute();

	// get row value
	$rows = $stmt->fetch(PDO::FETCH_NUM);

	// return count
	return $rows[0];
}

6.10 Template to display products

The previous section won’t work without “read_products_template.php”, so create that file and put the following code.

<?php
if(!isset($_SESSION['cart'])){
	$_SESSION['cart']=array();
}

while ($row = $stmt->fetch(PDO::FETCH_ASSOC)){
	extract($row);

	// creating box
	echo "<div class='col-md-4 m-b-20px'>";

		// product id for javascript access
		echo "<div class='product-id display-none'>{$id}</div>";

		echo "<a href='product.php?id={$id}' class='product-link'>";
			// select and show first product image
			$product_image->product_id=$id;
			$stmt_product_image=$product_image->readFirst();

			while ($row_product_image = $stmt_product_image->fetch(PDO::FETCH_ASSOC)){
				echo "<div class='m-b-10px'>";
					echo "<img src='uploads/images/{$row_product_image['name']}' class='w-100-pct' />";
				echo "</div>";
			}

			// product name
			echo "<div class='product-name m-b-10px'>{$name}</div>";
		echo "</a>";

		// add to cart button
		echo "<div class='m-b-10px'>";
			if(array_key_exists($id, $_SESSION['cart'])){
				echo "<a href='cart.php' class='btn btn-success w-100-pct'>";
					echo "Update Cart";
				echo "</a>";
			}else{
				echo "<a href='add_to_cart.php?id={$id}&page={$page}' class='btn btn-primary w-100-pct'>Add to Cart</a>";
			}
		echo "</div>";

	echo "</div>";
}

include_once "paging.php";
?>

6.11 Add “readFirst()” method

Add “readFirst()” method in “objects/product_image.php” file. The previous section will not work without it.

// read the first product image related to a product
function readFirst(){

	// select query
	$query = "SELECT id, product_id, name
			FROM " . $this->table_name . "
			WHERE product_id = ?
			ORDER BY name DESC
			LIMIT 0, 1";

	// prepare query statement
	$stmt = $this->conn->prepare( $query );

	// sanitize
	$this->id=htmlspecialchars(strip_tags($this->id));

	// bind prodcut id variable
	$stmt->bindParam(1, $this->product_id);

	// execute query
	$stmt->execute();

	// return values
	return $stmt;
}

6.12 Make “add to cart” button work

Place the following code inside layout_foot.php file.

<script>
$(document).ready(function(){
	// add to cart button listener
	$('.add-to-cart-form').on('submit', function(){

		// info is in the table / single product layout
		var id = $(this).find('.product-id').text();
		var quantity = $(this).find('.cart-quantity').val();

		// redirect to add_to_cart.php, with parameter values to process the request
		window.location.href = "add_to_cart.php?id=" + id + "&quantity=" + quantity;
		return false;
	});
});
</script>

6.13 Create pagination file

The previous section won’t work without the paging.php file. Create paging.php with the following code.

<?php
echo "<div class='col-md-12'>";

    echo "<ul class='pagination m-b-20px m-t-0px'>";

    // button for first page
    if($page>1){
        echo "<li><a href='{$page_url}' title='Go to the first page.'>";
            echo "First Page";
        echo "</a></li>";
    }

    $total_pages = ceil($total_rows / $records_per_page);

    // range of links to show
    $range = 2;

    // display links to 'range of pages' around 'current page'
    $initial_num = $page - $range;
    $condition_limit_num = ($page + $range)  + 1;

    for ($x=$initial_num; $x<$condition_limit_num; $x++) {

        // be sure '$x is greater than 0' AND 'less than or equal to the $total_pages'
        if (($x > 0) && ($x <= $total_pages)) {

            // current page
            if ($x == $page) {
                echo "<li class='active'><a href=\"#\">$x <span class=\"sr-only\">(current)</span></a></li>";
            }

            // not current page
            else {
                echo "<li><a href='{$page_url}page=$x'>$x</a></li>";
            }
        }
    }

    // button for last page
    if($page<$total_pages){
        echo "<li>";
            echo "<a href='" . $page_url . "page={$total_pages}' title='Last page is {$total_pages}.'>";
                echo "Last Page";
            echo "</a>";
        echo "</li>";
    }

    echo "</ul>";
echo "</div>";
?>

7.0 How to add to cart?

7.1 Create add_to_cart.php

Create add_to_cart.php file because when ‘Add to cart’ button was clicked, that file with the following code inside will be executed.

<?php
// start session 
session_start();

// get the product id
$id = isset($_GET['id']) ? $_GET['id'] : "";
$quantity = isset($_GET['quantity']) ? $_GET['quantity'] : 1;
$page = isset($_GET['page']) ? $_GET['page'] : 1;

// make quantity a minimum of 1
$quantity=$quantity<=0 ? 1 : $quantity;

// add new item on array
$cart_item=array(
	'quantity'=>$quantity
);

/*
 * check if the 'cart' session array was created
 * if it is NOT, create the 'cart' session array
 */
if(!isset($_SESSION['cart'])){
	$_SESSION['cart'] = array();
}

// check if the item is in the array, if it is, do not add
if(array_key_exists($id, $_SESSION['cart'])){
	// redirect to product list and tell the user it was added to cart
	header('Location: products.php?action=exists&id=' . $id . '&page=' . $page);
}

// else, add the item to the array
else{
	$_SESSION['cart'][$id]=$cart_item;

	// redirect to product list and tell the user it was added to cart
	header('Location: products.php?action=added&page=' . $page);
}
?>

7.2 Create cart.php

Create cart.php with the following basic code.

<?php
// start session
session_start();

// connect to database
include 'config/database.php';

// include objects
include_once "objects/product.php";
include_once "objects/product_image.php";

// get database connection
$database = new Database();
$db = $database->getConnection();

// initialize objects
$product = new Product($db);
$product_image = new ProductImage($db);

// set page title
$page_title="Cart";

// include page header html
include 'layout_head.php';

// contents will be here 

// layout footer 
include 'layout_foot.php';
?>

7.3 Display message based on action

We’ll display message on cart.php based on given action. Put the following code after “include ‘layout_head.php’;” of the previous section.

$action = isset($_GET['action']) ? $_GET['action'] : "";

echo "<div class='col-md-12'>";
	if($action=='removed'){
		echo "<div class='alert alert-info'>";
			echo "Product was removed from your cart!";
		echo "</div>";
	}

	else if($action=='quantity_updated'){
		echo "<div class='alert alert-info'>";
			echo "Product quantity was updated!";
		echo "</div>";
	}
echo "</div>";

7.4 Display cart items

Put the following code based on the code of the previous section.

if(count($_SESSION['cart'])>0){

	// get the product ids
	$ids = array();
	foreach($_SESSION['cart'] as $id=>$value){
		array_push($ids, $id);
	}

	$stmt=$product->readByIds($ids);

	$total=0;
	$item_count=0;

	while ($row = $stmt->fetch(PDO::FETCH_ASSOC)){
        extract($row);

		$quantity=$_SESSION['cart'][$id]['quantity'];
		$sub_total=$price*$quantity;

		// =================
		echo "<div class='cart-row'>";
			echo "<div class='col-md-8'>";

				echo "<div class='product-name m-b-10px'><h4>{$name}</h4></div>";

				// update quantity
				echo "<form class='update-quantity-form'>";
					echo "<div class='product-id' style='display:none;'>{$id}</div>";
					echo "<div class='input-group'>";
						echo "<input type='number' name='quantity' value='{$quantity}' class='form-control cart-quantity' min='1' />";
							echo "<span class='input-group-btn'>";
								echo "<button class='btn btn-default update-quantity' type='submit'>Update</button>";
							echo "</span>";
					echo "</div>";
				echo "</form>";

				// delete from cart
				echo "<a href='remove_from_cart.php?id={$id}' class='btn btn-default'>";
					echo "Delete";
				echo "</a>";
			echo "</div>";

			echo "<div class='col-md-4'>";
				echo "<h4>&#36;" . number_format($price, 2, '.', ',') . "</h4>";
			echo "</div>";
		echo "</div>";
		// =================

		$item_count += $quantity;
		$total+=$sub_total;
	}

	echo "<div class='col-md-8'></div>";
	echo "<div class='col-md-4'>";
		echo "<div class='cart-row'>";
			echo "<h4 class='m-b-10px'>Total ({$item_count} items)</h4>";
			echo "<h4>&#36;" . number_format($total, 2, '.', ',') . "</h4>";
	        echo "<a href='checkout.php' class='btn btn-success m-b-10px'>";
	        	echo "<span class='glyphicon glyphicon-shopping-cart'></span> Proceed to Checkout";
	        echo "</a>";
		echo "</div>";
	echo "</div>";

}

// no products were added to cart
else{
	echo "<div class='col-md-12'>";
		echo "<div class='alert alert-danger'>";
			echo "No products found in your cart!";
		echo "</div>";
	echo "</div>";
}

7.5 Read products by IDs

The previous section will not work without the following “readByIds()” method inside “objects/product.php” file.

// read all product based on product ids included in the $ids variable
// reference http://stackoverflow.com/a/10722827/827418
public function readByIds($ids){

	$ids_arr = str_repeat('?,', count($ids) - 1) . '?';

	// query to select products
	$query = "SELECT id, name, price FROM " . $this->table_name . " WHERE id IN ({$ids_arr}) ORDER BY name";

	// prepare query statement
	$stmt = $this->conn->prepare($query);

	// execute query
	$stmt->execute($ids);

	// return values from database
	return $stmt;
}

8.0 How to update cart?

8.1 Update cart quantity with JavaScript

We have the ‘update’ button on cart.php file. When that button was clicked, a javascript code is triggered. Put the following code inside “$(document).ready(function(){” of layout_foot.php file.

// update quantity button listener
$('.update-quantity-form').on('submit', function(){

	// get basic information for updating the cart
	var id = $(this).find('.product-id').text();
	var quantity = $(this).find('.cart-quantity').val();

	// redirect to update_quantity.php, with parameter values to process the request
	window.location.href = "update_quantity.php?id=" + id + "&quantity=" + quantity;
	return false;
});

8.2 PHP script to update cart

The previous section will not work without the update_quantity.php file with the following code inside it.

<?php
session_start();

// get the product id
$id = isset($_GET['id']) ? $_GET['id'] : 1;
$quantity = isset($_GET['quantity']) ? $_GET['quantity'] : "";

// make quantity a minimum of 1
$quantity=$quantity<=0 ? 1 : $quantity;

// remove the item from the array
unset($_SESSION['cart'][$id]);

// add the item with updated quantity
$_SESSION['cart'][$id]=array(
	'quantity'=>$quantity
);

// redirect to product list and tell the user it was added to cart
header('Location: cart.php?action=quantity_updated&id=' . $id);
?>

8.3 How to remove product on cart?

We have the ‘remove’ button on cart.php file. When that button was clicked, the remove_from_cart.php file with the following code will be executed.

<?php
// start session
session_start();

// get the product id
$id = isset($_GET['id']) ? $_GET['id'] : "";
$name = isset($_GET['name']) ? $_GET['name'] : "";

// remove the item from the array
unset($_SESSION['cart'][$id]);

// redirect to product list and tell the user it was added to cart
header('Location: cart.php?action=removed&id=' . $id);
?>

8.4 Create the checkout page

The checkout page looks like the cart page but the items cannot be updated or removed. It just like the summary of orders. Create checkout.php with the following code.

<?php
// start session
session_start();

// connect to database
include 'config/database.php';

// include objects
include_once "objects/product.php";
include_once "objects/product_image.php";

// get database connection
$database = new Database();
$db = $database->getConnection();

// initialize objects
$product = new Product($db);
$product_image = new ProductImage($db);

// set page title
$page_title="Checkout";

// include page header html
include 'layout_head.php';

if(count($_SESSION['cart'])>0){

	// get the product ids
	$ids = array();
	foreach($_SESSION['cart'] as $id=>$value){
		array_push($ids, $id);
	}

	$stmt=$product->readByIds($ids);

	$total=0;
	$item_count=0;

	while ($row = $stmt->fetch(PDO::FETCH_ASSOC)){
        extract($row);

		$quantity=$_SESSION['cart'][$id]['quantity'];
		$sub_total=$price*$quantity;

		//echo "<div class='product-id' style='display:none;'>{$id}</div>";
		//echo "<div class='product-name'>{$name}</div>";

		// =================
		echo "<div class='cart-row'>";
			echo "<div class='col-md-8'>";

				echo "<div class='product-name m-b-10px'><h4>{$name}</h4></div>";
                echo $quantity>1 ? "<div>{$quantity} items</div>" : "<div>{$quantity} item</div>";

			echo "</div>";

			echo "<div class='col-md-4'>";
				echo "<h4>&#36;" . number_format($price, 2, '.', ',') . "</h4>";
			echo "</div>";
		echo "</div>";
		// =================

		$item_count += $quantity;
		$total+=$sub_total;
	}

	// echo "<div class='col-md-8'></div>";
	echo "<div class='col-md-12 text-align-center'>";
		echo "<div class='cart-row'>";
            if($item_count>1){
    			echo "<h4 class='m-b-10px'>Total ({$item_count} items)</h4>";
            }else{
                echo "<h4 class='m-b-10px'>Total ({$item_count} item)</h4>";
            }
			echo "<h4>&#36;" . number_format($total, 2, '.', ',') . "</h4>";
	        echo "<a href='place_order.php' class='btn btn-lg btn-success m-b-10px'>";
	        	echo "<span class='glyphicon glyphicon-shopping-cart'></span> Place Order";
	        echo "</a>";
		echo "</div>";
	echo "</div>";

}

else{
	echo "<div class='col-md-12'>";
		echo "<div class='alert alert-danger'>";
			echo "No products found in your cart!";
		echo "</div>";
	echo "</div>";
}

include 'layout_foot.php';
?>

8.5 Create place_order.php

We’ll use this file to show a “thank you” message and remove all items in the cart.

<?php
// start session
session_start();

// remove items from the cart
session_destroy();

// set page title
$page_title="Thank You!";

// include page header HTML
include_once 'layout_head.php';

echo "<div class='col-md-12'>";

	// tell the user order has been placed
	echo "<div class='alert alert-success'>";
		echo "<strong>Your order has been placed!</strong> Thank you very much!";
	echo "</div>";

echo "</div>";

// include page footer HTML
include_once 'layout_foot.php';
?>

9.0 How to make the product page?

9.1 Create product.php

Create product.php with the following basic code.

<?php
// start session
session_start();

// include classes
include_once "config/database.php";
include_once "objects/product.php";
include_once "objects/product_image.php";

// get database connection
$database = new Database();
$db = $database->getConnection();

// initialize objects
$product = new Product($db);
$product_image = new ProductImage($db);

// include page header HTML
include_once 'layout_head.php';

// content will be here

// include page footer HTML
include_once 'layout_foot.php';
?>

9.2 Read product details

Put the following code after “$product_image = new ProductImage($db);” code of the previous section.

// get ID of the product to be edited
$id = isset($_GET['id']) ? $_GET['id'] : die('ERROR: missing ID.');

// set the id as product id property
$product->id = $id;

// to read single record product
$product->readOne();

// set page title
$page_title = $product->name;

9.3 Read one product method

The previous section will not work without the “readOne()” method. Add the following method inside “objects/product.php” file.

// used when filling up the update product form
function readOne(){

	// query to select single record
	$query = "SELECT
				name, description, price
			FROM
				" . $this->table_name . "
			WHERE
				id = ?
			LIMIT
				0,1";

	// prepare query statement
	$stmt = $this->conn->prepare( $query );

	// sanitize
	$this->id=htmlspecialchars(strip_tags($this->id));

	// bind product id value
	$stmt->bindParam(1, $this->id);

	// execute query
	$stmt->execute();

	// get row values
	$row = $stmt->fetch(PDO::FETCH_ASSOC);

	// assign retrieved row value to object properties
	$this->name = $row['name'];
	$this->description = $row['description'];
	$this->price = $row['price'];
}

9.4 Display product thumbnails

When these product thumbnails were hovered, it displayes a larger version of the image. It is Amazon-style. Put the following code after the previous section’s code.

// set product id
$product_image->product_id=$id;

// read all related product image
$stmt_product_image = $product_image->readByProductId();

// count all relatd product image
$num_product_image = $stmt_product_image->rowCount();

echo "<div class='col-md-1'>";
	// if count is more than zero
	if($num_product_image>0){
		// loop through all product images
		while ($row = $stmt_product_image->fetch(PDO::FETCH_ASSOC)){
			// image name and source url
			$product_image_name = $row['name'];
			$source="uploads/images/{$product_image_name}";
			echo "<img src='{$source}' class='product-img-thumb' data-img-id='{$row['id']}' />";
		}
	}else{ echo "No images."; }
echo "</div>";

9.5 Read images related to product

The previous section section will not work without the “readByProductId()” method inside “objects/product_image.php” file.

// read all product image related to a product
function readByProductId(){

	// select query
	$query = "SELECT id, product_id, name
			FROM " . $this->table_name . "
			WHERE product_id = ?
			ORDER BY name ASC";

	// prepare query statement
	$stmt = $this->conn->prepare( $query );

	// sanitize
	$this->product_id=htmlspecialchars(strip_tags($this->product_id));

	// bind prodcut id variable
	$stmt->bindParam(1, $this->product_id);

	// execute query
	$stmt->execute();

	// return values
	return $stmt;
}

9.6 Display product image

Only one product image are displayed at a time. This part displays the larger product image based on the hovered product thumbnail. Put the following code after the previous section’s code.

echo "<div class='col-md-4' id='product-img'>";

	// read all related product image
	$stmt_product_image = $product_image->readByProductId();
	$num_product_image = $stmt_product_image->rowCount();

	// if count is more than zero
	if($num_product_image>0){
		// loop through all product images
		$x=0;
		while ($row = $stmt_product_image->fetch(PDO::FETCH_ASSOC)){
			// image name and source url
			$product_image_name = $row['name'];
			$source="uploads/images/{$product_image_name}";
			$show_product_img=$x==0 ? "display-block" : "display-none";
			echo "<a href='{$source}' target='_blank' id='product-img-{$row['id']}' class='product-img {$show_product_img}'>";
				echo "<img src='{$source}' style='width:100%;' />";
			echo "</a>";
			$x++;
		}
	}else{ echo "No images."; }
echo "</div>";

9.7 Make image hover work

Put the following jQuery code inside “$(document).ready(function(){” of layout_foot.php file.

// change product image on hover
$(document).on('mouseenter', '.product-img-thumb', function(){
	var data_img_id = $(this).attr('data-img-id');
	$('.product-img').hide();
	$('#product-img-'+data_img_id).show();
});

9.8 Display product details

This part display product price, description and category. Put the following code after the previous section’s code.

echo "<div class='col-md-5'>";

	echo "<div class='product-detail'>Price:</div>";
	echo "<h4 class='m-b-10px price-description'>&#36;" . number_format($product->price, 2, '.', ',') . "</h4>";

	echo "<div class='product-detail'>Product description:</div>";
	echo "<div class='m-b-10px'>";
		// make html
		$page_description = htmlspecialchars_decode(htmlspecialchars_decode($product->description));

		// show to user
		echo $page_description;
	echo "</div>";

	echo "<div class='product-detail'>Product category:</div>";
	echo "<div class='m-b-10px'>{$product->category_name}</div>";

echo "</div>";

9.9 Render ‘Cart’ button

Now we will display ‘Add to cart’ button if the product is not yet added to cart. Else, we will display ‘update cart’ button.

echo "<div class='col-md-2'>";

	// if product was already added in the cart
	if(array_key_exists($id, $_SESSION['cart'])){
		echo "<div class='m-b-10px'>This product is already in your cart.</div>";
		echo "<a href='cart.php' class='btn btn-success w-100-pct'>";
			echo "Update Cart";
		echo "</a>";

	}

	// if product was not added to the cart yet
	else{

		echo "<form class='add-to-cart-form'>";
			// product id
			echo "<div class='product-id display-none'>{$id}</div>";

			echo "<div class='m-b-10px f-w-b'>Quantity:</div>";
			echo "<input type='number' value='1' class='form-control m-b-10px cart-quantity' min='1' />";

			// enable add to cart button
			echo "<button style='width:100%;' type='submit' class='btn btn-primary add-to-cart m-b-10px'>";
				echo "<span class='glyphicon glyphicon-shopping-cart'></span> Add to cart";
			echo "</button>";

		echo "</form>";
	}
echo "</div>";

10.0 What People Say About This Code?

I’m so glad that this code delights other people. The following are some of them from the comments section!

★★★★★ “Hey Mike, my name is Leonardo from Argentina. I’ve been reading your blog since like 4 months from now, and I really must say: your tutorials are very good, they has helped me in many of my works… Well, thank you very much man. I really admire your work.” ~ Leonardo

★★★★★ “Man, your tut’s are awesome. Im so glad ive found your blog. Big respect!” ~ Milos

★★★★★ “I bought your level-2 source code and it was so good, very big help for me. It was worth it. Thank you very much!” ~ Ashley Deanna Plata

★★★★★ “Hello, This is a great script and I have paid 6.99 for your work (it Worth it).” ~ Louis Blais

★★★★★ “Words can’t express how grateful I am for the work and the articles you post, had some troubles with doing somethings but your articles as per usual hit the hammer right on the head. They are a great way for expanding upon later too!” ~ Jeremy Smith

11.0 How to run the source code?

We highly recommend for you to follow and study our well-detailed, step-by-step tutorial above first. Nothing beats experience when it comes to learning.

But we believe you will learn faster if you’ll see the final source code as well. We consider it as your additional guide.

Imagine the value or skill upgrade it can bring you. The additional income you can get from your work, projects or business. The precious time you save. Isn’t that what you want?

By now, you need to download our source codes. To do it, use any download buttons in the next few sections below.

Once you downloaded the source codes, here’s how you can run it.

  1. Extract the files to your server directory.
  2. Go to your PhpMyAdmin, create a database with a name “shop_cart_sessions_1”.
  3. Import the “shop_cart_sessions_1.sql” file located in the “README” folder.
  4. You might need to change database credentials in /config/database.php
  5. Run “products.php”, this is the main PHP file. We do not have index.php

12.0 Download the LEVEL 1 Source Code

FEATURE LEVEL 1
Learn to code a simple cart function YES
List all products from MySQL database YES
Pagination on products list page YES
Add to cart action button YES
Remove from cart action button Yes
Update cart quantity YES
Checkout Page YES
Place order / Thank you page YES
Amazon-style product details page YES
Change image on hover of thumbnail YES
Show message about a product added to cart YES
Show message about a product removed from cart YES
Navigation bar highlights which page is selected YES
Cart link shows count of products added in the cart YES
Show message if no products found in database YES
Show message if no product found in cart YES
Bootstrap enabled UI YES
Cart page that lists all products added to cart YES
Auto-compute total cost of all products added to cart YES
PDO extension used YES
Step by step tutorial YES
Free source code updates YES
Free support for 6 months YES

THANK YOU!

has been added to your cart!

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Thank you!

have been added to your cart!

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13.0 Download the LEVEL 2 Source Code

FEATURE LEVEL 2
All features of LEVEL 1 source code YES
Navigation bar has drop down of product categories YES
Highlight selected category in drop down YES
Categories are retrieved from the database YES
Show products by category YES
List products under a category with pagination YES
Search product YES
Search results with pagination YES
Search box located on upper right corner of navigation bar YES
Search box requires search term before clicking the search button YES
Add to cart action button YES
Quantity text box beside the add to cart button YES
Quantity text box required to be a number YES
Quantity text box required to have a minimum value of 1, negative value not allowed YES
Remember the page number where the user clicked the “Add to cart” button YES
Quantity drop down options based on available stock YES
Well formatted money value YES
Check out button with cart icon YES
Product image viwable in lightbox YES
Shows number of stock left YES
Stock decreases once checked out YES
Order saved in orders and order_items table in the database YES
Emtpy cart button YES
Emtpy cart confirmation pop up YES
Bootstrap enabled UI YES
Cart page that lists all products added to cart YES
Quantity text box beside update quantity button YES
Show price, category and stocks left in product list page YES
Auto-compute total cost of all products added to cart YES
Used PDO bindParam() to prevent SQL injection in MySQL queries YES
Used PHP htmlspecialchars() to prevent XSS attacks YES
SQL file is in the “dev” folder YES
PDO extension used YES
Free code updates YES
Free support for 6 months YES

THANK YOU!

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Thank you!

have been added to your cart!

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14.0 PHP Shopping Cart Module

You can download our “PHP Shopping Cart & Ordering Module” source code. It has several features you need to learn more about how to handle the users, shopping cart, and ordering using the PHP & MySQL technology. CLICK HERE TO LEARN MORE

15.0 PHP Shopping Cart System

You can download our “PHP Shopping Cart System” source code as well. Many of you requested this type of source code and not it is here!

You needed a shopping cart system with user management (merchant and customer), product management, order management, security and more features based on our source codes here in codeofaninja.com. CLICK HERE TO LEARN MORE.

16.0 What’s Next?

We just learned how to code an online shopping cart from scratch using PHP SESSIONS.

But did you know that we can create the almost the same functions using another PHP mechanism called COOKIES?

If you’re excited to learn this new concept, let us go to the next tutorial: PHP Shopping Cart Tutorial Using COOKIES

17.0 Related Tutorials

18.0 Some Notes

#1 Found An Issue?

If you found a problem with this code, we can solve it faster via Email or FB message, please send me a message via email mike@codeofaninja.com, or via our official Facebook page!

Please be more detailed about your issue. Best if you can provide an error message and your test or page URL. Thanks!

Please feel free to comment if you have any questions, suggestions, found something wrong or want to contribute to this code.

#2 Become a true Ninja!

We constantly add new tutorials and improve our existing tutorials and source codes. Be one of the first to know an update by subscribing to our FREE newsletter. Get a FREE EBOOK as well. CLICK HERE TO SUBSCRIBE FOR FREE!

#3 Thank You!

Thank you for studying our tutorial about PHP Shopping Cart Tutorial using SESSIONS!