How to make a purchase of a limited quantity item?

Question

Database design

How are tasks such as "purchasing a movie ticket", "purchasing goods", etc. solved? where is the quantity limit?
Interested in how to make it so that while one person confirms his purchase, and there is only one product left, the other buyer is not ahead of him?

Answer 1

Through transactions .
https://habr.com/en/post/317884/

Answer 2

Describe the scenario in more detail - what the person has already followed before confirming the purchase.
As I understand it - when a person picks up a product in the basket, you need to remove this product from the warehouse; then no one can intercept it. There is a problem here - if a person took the goods into the basket, turned off his computer and went on vacation; those. the cart must be timed out.
But perhaps someone sees the goods in the warehouse, wants to take them to their basket - oh, but they have already taken them.