用PHP开发的商城购物车数据清理与优化策略分析

// 获取过期时间
$expireTime = time() - (7 * 24 * 3600); 

// 查询购物车中过期的商品
$sql = "DELETE FROM shopping_cart WHERE expiry_time < $expireTime";
$result = mysqli_query($conn, $sql);
if (!$result) {
    echo "清理购物车失败：" . mysqli_error($conn);
} else {
    echo "成功清理购物车中过期的商品";
}

// 查询购物车中无效的商品
$sql = "DELETE FROM shopping_cart WHERE NOT EXISTS (SELECT 1 FROM products WHERE shopping_cart.product_id = products.id)";
$result = mysqli_query($conn, $sql);
if (!$result) {
    echo "清理购物车失败：" . mysqli_error($conn);
} else {
    echo "成功清理购物车中无效的商品";
}

// 合并购物车中相同的商品
$sql = "SELECT product_id, SUM(quantity) AS total_quantity FROM shopping_cart GROUP BY product_id";
$result = mysqli_query($conn, $sql);
while ($row = mysqli_fetch_assoc($result)) {
    $productId = $row['product_id'];
    $totalQuantity = $row['total_quantity'];
    
    // 更新购物车中商品数量
    $sqlUpdate = "UPDATE shopping_cart SET quantity = $totalQuantity WHERE product_id = $productId";
    mysqli_query($conn, $sqlUpdate);
}

echo "成功合并购物车中相同的商品";

// 存储购物车数据至缓存中
if (!$cartData = getFromCache('shopping_cart')) {
    $sql = "SELECT * FROM shopping_cart WHERE user_id = $userId";
    $result = mysqli_query($conn, $sql);
    $cartData = [];
    while ($row = mysqli_fetch_assoc($result)) {
        $cartData[] = $row;
    }
    saveToCache('shopping_cart', $cartData);
}

// 从缓存中读取购物车数据
function getFromCache($key) {
    // 从缓存中获取数据
    // ...
    return $data;
}

// 将购物车数据存储至缓存中
function saveToCache($key, $data) {
    // 将数据存储至缓存中
    // ...
}