March 6, 2012
PHP shopping cart doesn't show numerous products
Question by Carla Dessi
i’ve made a php shopping cart, it shows all the products on the home screen, you can click on them and add them to your basket, then you are taken to the shopping cart screen. this only shows one product but with a quantity of how many different products you’ve added, even if they all have different titles. the total price and quantity work, its only the product name that doesn’t. This is my code..
<?php
session_start();
include "connect.php";
include "header.php";
function viewcart(){
if (isset($_SESSION['cart'])){ //if shopping cart is not empty
$cart = $_SESSION['cart']; //store the cart array into a variable then display the content
echo "<table border="1"><tr><th>Product Name</th><th>Quantity</th><th>Delete</th></tr>";
foreach ($cart as $product=>$quantity){
$q = "SELECT ID, Name FROM Products";
$result = mysqli_query($_SESSION['conn'],$q);
$row = mysqli_fetch_array($result);
$product_id = $row[0];
echo "<tr><td>$product</td><td>$quantity</td><td><a href="?action=delete&product=$product_id">-</a></td></tr>";
mysqli_free_result($result);
}
echo "</table>";
subtotal($cart); //display the subtotal
} else { //if shopping cart is empty
echo "<p>There is no product in your shopping cart.</p>";
}
}
function addproduct($product_id, $product_qty){
$q = "SELECT ID, Name FROM Products";
$result = mysqli_query($_SESSION['conn'],$q)
or die("Error: ".mysqli_error($_SESSION['conn']));
$row = mysqli_fetch_array($result);
$product_name = $row[1]; //get the product name from product id because it is better to display name than id in the cart
if (isset($_SESSION['cart'])){ //if shopping cart is not empty
$cart = $_SESSION['cart'];
if (array_key_exists($product_name, $cart)){ //if the product exists, update quantity
$cart[$product_name] += $product_qty;
}
else { //otherwise, add new product-quantity pair to the array
$cart[$product_name]=$product_qty;
}
$_SESSION['cart'] = $cart; //write the updated array back to session variable
}
else { //if shopping cart is empty
$cart = array($product_name=>$product_qty); //add product and quantity to the shopping cart
$_SESSION['cart'] = $cart; //write the updated array back
}
mysqli_free_result($result);
}
function deleteproduct($product_id, $product_qty){
$q = "SELECT Name FROM Products";
$result = mysqli_query($_SESSION['conn'],$q);
$row = mysqli_fetch_array($result);
$product_name = $row['Name'];
if (isset($_SESSION['cart'])){ //if shopping cart is not empty
$cart = $_SESSION['cart'];
if (array_key_exists($product_name, $cart)){ //if the product exists, update quantity
$cart[$product_name] -= $product_qty;
if ($cart[$product_name] == 0){ //if the quantity is 0, delete the key
unset($cart[$product_name]);
}
}
else { //exception
echo "<p>Error!</p>";
}
$_SESSION['cart'] = $cart; //write the updated array back to session variable
} else {
echo "<p>Error!</p>";
}
mysqli_free_result($result);
}
function emptycart(){
if (isset($_SESSION['cart'])){ //if shopping cart is not empty
unset($_SESSION['cart']);
}
else {
echo "<p>Error!</p>";
}
}
function subtotal($cart){ //calculate the total value of products in the shopping cart
$total = 0; //initialise total
if (!empty($cart)){
foreach ($cart as $product => $quantity){
$q = "SELECT ID, Price FROM Products";
$result = mysqli_query($_SESSION['conn'],$q);
$row = mysqli_fetch_array($result);
$price = $row['Price'];
$total += $price * $quantity;
}
echo "<p>Total: $total | <a href="?action=empty">Empty cart</a></p>";
} else {
unset($_SESSION['cart']); //do not need to keep an empty cart, so delete it
echo "<p>There is no product in your shopping cart.</p>";
}
}
if (isset($_GET['action'])){
if ($_GET['action']=='view'){
viewcart();
} elseif ($_GET['action']=='add'){
if (isset($_GET['product'])){
$product_id = $_GET['product'];
$product_qty = 1; //default product value
addproduct($product_id, $product_qty);
viewcart();
echo "<p><a href="javascript:history.go(-1)">back</a></p>";
} else {
echo "<p>There is an error! Are you trying to attack this little poor shopping cart?</p>";
}
} elseif ($_GET['action'] == 'delete'){
if (isset($_GET['product'])){
$product_id = $_GET['product'];
$product_qty = 1; //default product value
deleteproduct($product_id, $product_qty);
viewcart();
}
else {
echo "<p>There is an error! </p>";
}
} elseif ($_GET['action']=='empty'){
emptycart();
viewcart();
}
else {
echo "<p>There is an error! </p>";
}
}
else {
echo "<p>There is an error! </p>";
}
include "footer.php";
?>
Answer by Starx
You have a typo in your query. May be you wanted to extract the product id of the product, but, in fact selecting everything in a table.
$q = "SELECT ID, Name FROM Products";
Update it, to read something like the example below and check if this fixes the problem
$q = "SELECT ID, Name FROM `Products` WHERE name='$product' ";
And later you are reading the result as
$row = mysqli_fetch_array($result);
I hope you know that, this way $row will only get the first row it gets from the table.
