How to implement a shopping cart function using php+mysql

1. Overview of Shopping Cart Function

Consider the shopping cart as the core function of the online mall. Users can add the items they need to purchase to the shopping cart. Prepare for future orders. To better manage orders and payments, the shopping cart allows users to change item quantities and delete items.

2. Basic steps to implement a shopping cart

Before using PHP and MySQL to implement the shopping cart function, let us first take a look at the basic steps to implement a shopping cart:

• Create database table: We need to create a database table to store shopping cart information.

• Write the code to add to the shopping cart: When the user adds items to the shopping cart, the corresponding data needs to be added to the database.

• Write the code to display the shopping cart: When the user views the shopping cart, relevant data needs to be obtained from the database and displayed.

• Write code to modify the shopping cart: When the user modifies or deletes an item in the shopping cart, the corresponding data in the database needs to be updated.

3. Create a database table

First, we need to create a database table to store shopping cart information. Here is an example:

CREATE TABLE `cart` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `product_name` varchar(255) NOT NULL,
  `product_price` decimal(10,2) NOT NULL,
  `product_quantity` int(11) NOT NULL,
  `user_id` int(11) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

In this table, we will store the following information:

• Product name: product_name

• Product price: product_price

• Product quantity: product_quantity

• User ID: user_id

4. Write the code to add to the shopping cart

When the user adds items to the shopping cart, the corresponding data needs to be added to the database. The following is a basic code example for adding items to the shopping cart:

<?php

$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";

// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname);

// 检查连接是否成功
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

// 获取要添加到购物车的商品信息
$product_name = $_POST[&#39;product_name&#39;];
$product_price = $_POST[&#39;product_price&#39;];
$product_quantity = $_POST[&#39;product_quantity&#39;];
$user_id = $_POST[&#39;user_id&#39;];

// 将商品添加到购物车
$sql = "INSERT INTO cart (product_name, product_price, product_quantity, user_id) 
VALUES (&#39;$product_name&#39;, &#39;$product_price&#39;, &#39;$product_quantity&#39;, &#39;$user_id&#39;)";

if ($conn->query($sql) === TRUE) {
    echo "商品已成功添加到购物车。";
} else {
    echo "Error: " . $sql . "<br>" . $conn->error;
}

$conn->close();

?>

Please note that here we use mysqli to connect to the MySQL database and perform some basic connection checks before adding data.

5. Write the code to display the shopping cart

When the user views the shopping cart, the relevant data needs to be obtained from the database and displayed. Here is a basic code example that displays shopping cart information:

<?php

$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";

// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname);

// 检查连接是否成功
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

// 获取购物车信息
$sql = "SELECT * FROM cart WHERE user_id = &#39;123&#39;"; // 请将user_id替换为当前登录用户的ID

$result = $conn->query($sql);

if ($result->num_rows > 0) {
    // 输出每一行数据
    while($row = $result->fetch_assoc()) {
        echo "商品名称:" . $row["product_name"]. "，价格：" . $row["product_price"]. "，数量：" . $row["product_quantity"]. "<br>";
    }
} else {
    echo "购物车为空。";
}

$conn->close();

?>

Please note that here we check if the result set contains any rows and use a while loop to output each row of data.

6. Write the code to modify the shopping cart

If the user modifies or deletes an item in the shopping cart, the corresponding database data must be updated. Here's a basic code example that modifies the contents of a shopping cart:

<?php

$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";

// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname);

// 检查连接是否成功
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

// 获取要修改的商品信息
$product_name = $_POST[&#39;product_name&#39;];
$product_price = $_POST[&#39;product_price&#39;];
$product_quantity = $_POST[&#39;product_quantity&#39;];
$user_id = $_POST[&#39;user_id&#39;];

// 更新购物车中商品信息
$sql = "UPDATE cart SET product_price = &#39;$product_price&#39;, product_quantity = &#39;$product_quantity&#39; WHERE user_id = &#39;$user_id&#39; AND product_name = &#39;$product_name&#39;";

if ($conn->query($sql) === TRUE) {
    echo "购物车信息已成功更新。";
} else {
    echo "Error: " . $sql . "<br>" . $conn->error;
}

$conn->close();

?>

The above is the detailed content of How to implement a shopping cart function using php+mysql. For more information, please follow other related articles on the PHP Chinese website!