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php实现购买

2026-01-30 03:38:16PHP

PHP实现购买功能的基本步骤

创建一个PHP购买功能通常涉及以下几个关键环节，以下是一个简化但完整的实现方案：

数据库设计

需要设计相关数据表存储商品、订单和用户信息。常见表结构如下：

php实现购买

products表：存储商品ID、名称、价格、库存等
users表：存储用户ID、余额等信息
orders表：存储订单ID、用户ID、商品ID、数量、总价、下单时间等

示例SQL创建语句：

CREATE TABLE products (
    id INT AUTO_INCREMENT PRIMARY KEY,
    name VARCHAR(100) NOT NULL,
    price DECIMAL(10,2) NOT NULL,
    stock INT NOT NULL
);

CREATE TABLE users (
    id INT AUTO_INCREMENT PRIMARY KEY,
    username VARCHAR(50) NOT NULL,
    balance DECIMAL(10,2) DEFAULT 0.00
);

CREATE TABLE orders (
    id INT AUTO_INCREMENT PRIMARY KEY,
    user_id INT NOT NULL,
    product_id INT NOT NULL,
    quantity INT NOT NULL,
    total_price DECIMAL(10,2) NOT NULL,
    order_date TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    FOREIGN KEY (user_id) REFERENCES users(id),
    FOREIGN KEY (product_id) REFERENCES products(id)
);

商品展示页面

创建一个显示商品列表的页面，允许用户选择商品并添加到购物车。

php实现购买

<?php
// 连接数据库
$db = new PDO('mysql:host=localhost;dbname=shop', 'username', 'password');

// 查询商品
$query = $db->query("SELECT * FROM products WHERE stock > 0");
$products = $query->fetchAll(PDO::FETCH_ASSOC);

// 显示商品列表
foreach ($products as $product) {
    echo "<div>";
    echo "<h3>{$product['name']}</h3>";
    echo "<p>价格: {$product['price']}元</p>";
    echo "<p>库存: {$product['stock']}</p>";
    echo "<form method='post' action='add_to_cart.php'>";
    echo "<input type='hidden' name='product_id' value='{$product['id']}'>";
    echo "<input type='number' name='quantity' min='1' max='{$product['stock']}' value='1'>";
    echo "<button type='submit'>加入购物车</button>";
    echo "</form>";
    echo "</div>";
}
?>

购物车功能

实现购物车功能，可以存储在session中。

// add_to_cart.php
session_start();

if (!isset($_SESSION['cart'])) {
    $_SESSION['cart'] = [];
}

$product_id = $_POST['product_id'];
$quantity = $_POST['quantity'];

// 检查商品是否已在购物车
if (isset($_SESSION['cart'][$product_id])) {
    $_SESSION['cart'][$product_id] += $quantity;
} else {
    $_SESSION['cart'][$product_id] = $quantity;
}

header('Location: cart.php');

结算页面

显示购物车内容并处理结算逻辑。

// checkout.php
session_start();

// 获取购物车商品详情
$cart = $_SESSION['cart'] ?? [];
$db = new PDO('mysql:host=localhost;dbname=shop', 'username', 'password');

// 开始事务
$db->beginTransaction();

try {
    $total = 0;
    foreach ($cart as $product_id => $quantity) {
        // 检查库存
        $stmt = $db->prepare("SELECT price, stock FROM products WHERE id = ? FOR UPDATE");
        $stmt->execute([$product_id]);
        $product = $stmt->fetch(PDO::FETCH_ASSOC);

        if ($quantity > $product['stock']) {
            throw new Exception("商品库存不足");
        }

        // 计算总价
        $subtotal = $product['price'] * $quantity;
        $total += $subtotal;

        // 更新库存
        $db->prepare("UPDATE products SET stock = stock - ? WHERE id = ?")
           ->execute([$quantity, $product_id]);
    }

    // 检查用户余额
    $user_id = $_SESSION['user_id'];
    $stmt = $db->prepare("SELECT balance FROM users WHERE id = ? FOR UPDATE");
    $stmt->execute([$user_id]);
    $user = $stmt->fetch(PDO::FETCH_ASSOC);

    if ($user['balance'] < $total) {
        throw new Exception("余额不足");
    }

    // 扣减余额
    $db->prepare("UPDATE users SET balance = balance - ? WHERE id = ?")
       ->execute([$total, $user_id]);

    // 创建订单
    foreach ($cart as $product_id => $quantity) {
        $stmt = $db->prepare("INSERT INTO orders (user_id, product_id, quantity, total_price) VALUES (?, ?, ?, ?)");
        $product = $db->query("SELECT price FROM products WHERE id = $product_id")->fetch();
        $stmt->execute([$user_id, $product_id, $quantity, $product['price'] * $quantity]);
    }

    // 清空购物车
    unset($_SESSION['cart']);

    $db->commit();
    echo "购买成功！";
} catch (Exception $e) {
    $db->rollBack();
    echo "购买失败: " . $e->getMessage();
}