MySQL implements the shopping cart function of the ordering system

MySQL implements the shopping cart function of the ordering system - code example

Introduction:
With the popularization of the Internet, the ordering system has become an important part of restaurant management One ring. In the ordering system, the shopping cart function is an indispensable part. It allows users to select dishes and perform operations such as adding, deleting, and modifying quantities. This article will introduce how to use the MySQL database to implement the shopping cart function of the ordering system and provide specific code examples.

1. Create database and table structure
First, create a database in MySQL and name it "menu_order". Then, create the following two table structures:

1. Dish table (menu)
   Remarks: Used to store available dish information.
   Table structure: id (int, primary key, auto-increment), name (varchar, dish name), price (decimal, dish price)
2. Shopping cart table (cart)
   Remarks: used Store the dish information selected by the user.
   Table structure: id (int, primary key, auto-increment), menu_id (int, dish ID, ID of the associated dish table), quantity (int, quantity of dishes)

2. Implement shopping Code example for the cart function
The following is a code example for implementing the shopping cart function in MySQL:

1. Add dishes to the shopping cart

   INSERT INTO cart (menu_id, quantity) VALUES (1, 2);

2. Delete a dish from the shopping cart

   DELETE FROM cart WHERE id = 1;

3. Modify the quantity of the dish in the shopping cart

   UPDATE cart SET quantity = 3 WHERE id = 1;

4. Query the dish information in the shopping cart

   SELECT c.id, m.name, m.price, c.quantity
   FROM cart c
   JOIN menu m ON c.menu_id = m.id;

5. Clear the shopping cart

   DELETE FROM cart;

3. Application examples of the shopping cart function
The following is an application example of the shopping cart function in the ordering system:

1. The user selects the dishes and adds them to the shopping cart

   INSERT INTO cart (menu_id, quantity) VALUES (1, 2);

2. The user views the selected dishes and quantity in the shopping cart

   SELECT c.id, m.name, m.price, c.quantity
   FROM cart c
   JOIN menu m ON c.menu_id = m.id;

   Output result:

   id | name   | price | quantity

3. | Tomato scrambled eggs | 18.00 | 2

4. The user modifies the quantity of a certain dish in the shopping cart

   UPDATE cart SET quantity = 3 WHERE id = 1;

5. The user deletes a dish from the shopping cart

   DELETE FROM cart WHERE id = 1;

6. The user clears the shopping cart

   DELETE FROM cart;

Conclusion:
Through the above sample code, we can see that the shopping cart function of the ordering system can be easily implemented using the MySQL database. Users can flexibly manage the dishes they choose by adding, deleting, modifying quantities and other operations. The shopping cart function greatly improves the user experience of the ordering system and helps restaurants improve efficiency.

However, the code examples provided in this article are only basic functional implementations. In actual development, other user interaction, order processing and other functions need to be added. In actual applications, it is also necessary to conduct comprehensive development in combination with front-end pages, back-end logic, etc. I hope the examples in this article can provide some reference and help for developers when implementing the shopping cart function of the ordering system.

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