How to correctly check if information has already been parsed?

Question

Parsing

Let's say we have a list of articles. The article has a title and a date.
During the initial parsing, all articles are added to the database.
Then, when running the script, only those articles that have not yet been parsed should be added to the database.
Question: what is the correct and most effective way to check whether an article is in the database or not? For what parameter to cling? Or do some unique ID based on some data?

Answer 1

in general

do some unique ID based on some data?

, only gygy, it won’t help - you still need to download to compare
, usually articles on the site have some unique ID, so cling to it