我正在尝试用PHP创建购物车。我理解如何使用硬编码产品的会话，但我很难尝试从SQL数据库中检索产品。
这是我到目前为止所做的 CART.php：
function add_item($key, $quantity) {
global $products;
if ($quantity < 1) return;
// If item already exists in cart, update quantity
if (isset($_SESSION['cart'][$key])) {
$quantity += $_SESSION['cart'][$key]['qty'];
update_item($key, $quantity);
return;
}
// Add item
$cost = $products[$key]['cost'];
$total = $cost * $quantity;
$item = array(
'name' => $products[$key]['name'],
'cost' => $cost,
'qty' => $quantity,
'total' => $total
);
$_SESSION['cart'][$key] = $item;
}
CART_VIEW.php
<h1>Your Cart</h1>
<?php if (empty($_SESSION['cart']) || count($_SESSION['cart']) == 0) : ?>
<p>There are no items in your cart.</p>
<?php else: ?>
<form action="." method="post">
<input type="hidden" name="action" value="update">
<table>
<tr id="cart_header">
<th class="left">Item</th>
<th class="right">Item Cost</th>
<th class="right">Quantity</th>
<th class="right">Item Total</th>
</tr>
<?php foreach( $_SESSION['cart'] as $key => $item ) :
$cost = number_format($item['cost'], 2);
$total = number_format($item['total'], 2);
?>
<tr>
<td>
<?php echo $item['name']; ?>
</td>
<td class="right">
$<?php echo $cost; ?>
</td>
<td class="right">
<input type="text" class="cart_qty"
name="newqty[<?php echo $key; ?>]"
value="<?php echo $item['qty']; ?>">
</td>
<td class="right">
$<?php echo $total; ?>
</td>
</tr>
<?php endforeach; ?>
<tr id="cart_footer">
<td colspan="3"><b>Subtotal</b></td>
<td>$<?php echo get_subtotal(); ?></td>
</tr>
<tr>
<td colspan="4" class="right">
<input type="submit" value="Update Cart">
</td>
ADD_ITEM.php
<h1>Add Item</h1>
<form action="../cart/index.php" method="post">
<input type="hidden" name="action" value="add">
<label>Name:</label>
<section>
<h1><?php echo $name; ?></h1>
<div id="left_column">
<p>
</p>
<select name="productkey">
<?php foreach($products as $key => $product) :
$cost = number_format($product['cost'], 2);
$name = $product['name'];
$item = $name . ' ($' . $cost . ')';
?>
<option value="<?php echo $key; ?>">
<?php echo $item; ?>
</option>
<?php endforeach; ?>
</select><br>
<label>Quantity:</label>
<select name="itemqty">
<?php for($i = 1; $i <= 10; $i++) : ?>
<option value="<?php echo $i; ?>">
<?php echo $i; ?>
</option>
<?php endfor; ?>
</select><br>
<label> </label>
<input type="submit" value="Add Item">
</form>
的index.php
<?php
$lifetime = 60 * 60 * 24 * 365 * 4; // 3 years in seconds
session_set_cookie_params($lifetime, '/');
session_start();
// Create a cart array if needed
if (empty($_SESSION['cart'])) { $_SESSION['cart'] = array(); }
// Create a table of products
$products = array(); //hard coded products <------------
$products['MMS-1754'] = array('name' => 'PC', 'cost' => '549.50');
// Include cart functions
require_once('cart.php');
// Get the action to perform
$action = filter_input(INPUT_POST, 'action');
if ($action === NULL) {
$action = filter_input(INPUT_GET, 'action');
if ($action === NULL) {
$action = 'show_add_item';
}
}
// Add or update cart as needed
switch($action) {
case 'add':
$product_key = filter_input(INPUT_POST, 'productkey');
$item_qty = filter_input(INPUT_POST, 'itemqty');
add_item($product_key, $item_qty);
include('cart_view.php');
break;
case 'show_cart':
include('cart_view.php');
break;
case 'show_add_item':
include('add_item_view.php');
break;
case 'end_session':
// Clear session data from memory
$_SESSION = array();
// Clean up session ID
session_destroy(); ...
products_db
<?php
function get_products() {
global $db;
$query = 'SELECT productID, categoryID, productName,description,price,imageFile
FROM products
ORDER BY productID' ;
$statement = $db->prepare($query);
$statement->execute();
$products = $statement->fetchAll();
$statement->closeCursor();
return $products;
}
function get_products_by_name($product_id) {
global $db;
$query = 'SELECT * FROM products
WHERE products.productName = :product_id';
$statement = $db->prepare($query);
$statement->bindValue(":product_id", $product_id);
$statement->execute();
$product_name = $statement->fetchAll();
$statement->closeCursor();
return $product_name;
}
function get_products_by_category($category_id) {
global $db;
$query = 'SELECT * FROM products
WHERE products.categoryID = :category_id
ORDER BY productID';
$statement = $db->prepare($query);
$statement->bindValue(":category_id", $category_id);
$statement->execute();
$product = $statement->fetchAll();
$statement->closeCursor();
return $product;
}
function get_product($product_id) {
global $db;
$query = 'SELECT * FROM products
WHERE productID = :product_id';
$statement = $db->prepare($query);
$statement->bindValue(":product_id", $product_id);
$statement->execute();
$product = $statement->fetch();
$statement->closeCursor();
return $product;
}
我需要不同的功能吗？我尝试使用产品ID并使用GET数组，但会话将打印为null（使用var-dump进行检查）。