How to track records in the database for products that have disappeared from the supplier's website?

Question

PHP

The crux of the matter is this. There is a python parser. He visits the supplier's website, parses the goods, then makes a request to the database, and if there is no such product, then adds it. There are no problems with this. But how to track which products are in the database but disappeared from the supplier's website? You only need an algorithm, there are no problems with bydlocking)))

Answer 1

The simplest thing that comes to mind is to do the reverse process: that is, take goods from the database and check if they are on the site.

Answer 2

Turn off all products or change availability, and then turn it on as you bypass the supplier