Implementation method of shopping cart function in PHP developer mall

How to implement the shopping cart function in PHP Developer City

With the development of the e-commerce industry, more and more enterprises and individual merchants choose to build their own online malls to conduct business. As one of the important functions of the e-commerce platform, the shopping cart is responsible for key links such as product selection, adding to the shopping cart, and settlement. This article will introduce how to use PHP language to implement a simple and efficient shopping cart function.

1. Database design
First, we need to design the database structure required for the shopping cart. Generally speaking, the shopping cart function requires two main database tables: the product table and the shopping cart table.

1. Product table: used to store all product information, including product ID, name, price, inventory, etc. The following table structure can be used:

CREATE TABLE product (
id int(11) NOT NULL AUTO_INCREMENT,
name varchar(255) NOT NULL,
price decimal(10,2) NOT NULL,
stock int(11) NOT NULL,
PRIMARY KEY (id)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

2. Shopping cart table: used to store the user's shopping cart information, including shopping cart ID, Product ID, quantity, etc. The following table structure can be used:

CREATE TABLE cart (
id int(11) NOT NULL AUTO_INCREMENT,
product_id int(11) NOT NULL,
quantity int(11) NOT NULL,
PRIMARY KEY (id)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

2. Implementation of shopping cart function
After the database design is completed, we can start to implement the shopping cart function.

1. Add product to shopping cart: When the user clicks the add product button, we insert the product ID and quantity into the shopping cart table through PHP code. This can be achieved using the following code:

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

// First Check whether the product already exists in the shopping cart table
$checkCartItemQuery = "SELECT * FROM cart WHERE product_id = $productId";
$checkCartItemResult = $conn->query($checkCartItemQuery);

if ($checkCartItemResult->num_rows > 0) {
// Update the quantity of items already in the cart
$updateCartItemQuery = "UPDATE cart SET quantity = quantity $quantity WHERE product_id = $productId";
$conn->query($updateCartItemQuery);
} else {
// Insert new items into the shopping cart
$insertCartItemQuery = "INSERT INTO cart (product_id, quantity) VALUES ($ productId, $quantity)";
$conn->query($insertCartItemQuery);
}

2. Modify the quantity of items in the shopping cart: When the user changes the quantity of items in the shopping cart , we need to update the quantity of the corresponding product in the shopping cart table. This can be achieved using the following code:

$cartItemId = $_POST['cart_item_id'];
$quantity = $_POST['quantity'];

// Update The quantity of items in the shopping cart
$updateCartItemQuery = "UPDATE cart SET quantity = $quantity WHERE id = $cartItemId";
$conn->query($updateCartItemQuery);

3. Delete items in the shopping cart: When the user clicks the delete button, we need to delete the corresponding shopping cart item from the shopping cart table. You can use the following code to achieve this:

$cartItemId = $_POST['cart_item_id'];

// Delete items from the shopping cart
$deleteCartItemQuery = "DELETE FROM cart WHERE id = $cartItemId";
$conn->query($deleteCartItemQuery);

4. Get the list of items in the shopping cart: When the user enters the shopping cart page, we need to Get the user's shopping cart information from the shopping cart table. You can use the following code to achieve this:

// Get the list of products in the shopping cart
$cartItemsQuery = "SELECT cart.id, product.id as product_id, product.name, product.price , cart.quantity
FROM cart
INNER JOIN product ON cart.product_id = product.id";
$cartItemsResult = $conn->query($cartItemsQuery);

while ( $row = $cartItemsResult->fetch_assoc()) {
// Output the product information in the shopping cart here
}

Through the above code implementation, we can easily implement a Basic shopping cart functionality. Of course, according to actual needs, we can add more functions, such as clearing the shopping cart, checkout, etc.

Summary:
The shopping cart function is one of the indispensable core functions of the e-commerce platform. By using PHP language and appropriate database design, we can flexibly implement an efficient and easy-to-use shopping cart. Function. I hope that the introduction in this article will be helpful to the implementation of the shopping cart function in the PHP Developer City.

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