What happens in a supermarket when a barcode is read at the checkout?

My blog https://blog.youkuaiyun.com/zhangxingping/article/details/116346886 gives a detailed description of how a barcode scanner reads a barcode.

This blog gives you a general description of what happens in a supermarket when a barcode is read at the checkout.

1. A supermarket has a database server which is used stores the information about the goods they are selling, including the descriptions, prices, numbers of stock items.
2. The barcode uniquely identifies each item.
3. When a barcode is scanned, its equivalent number is searched for in the stock database.
4. The stock item is found by using the barcode number and the description and price are send back to the checkout and they are displayed on the monitor.
5. The number of stock item is reduced by one each time the barcode is read.
6. The new number is checked against the re-order level. If it is less than or equal to this value and the item is not re-ordered, more stock items are re-ordered automatically.
7. An item is marked reordered to prevent the duplication of reorder each time a reorder is make.

The advantages of using barcodes:

To the management:

• easier and faster to find the price of each item.
• easier to update sales information
• allows for automatic stock control.

To the customer:

• quicker checkout queue. (Entering the numbers of goods that you purchase manually is slow and error-prone)
• quicker and correct charge. (The computer can do the calculation much faster and it does not make mistakes.)
• under the control of computer, an itemized bill can be given to the customer.