PHP + mysql notification system. How to do it better?

Question

PHP

Hello. I am creating my own project. Made already registration and authorization of users. I don’t really understand how to make the notification system about LIKES or COMMENTS. There will be a table with records, etc. So far, I'm thinking about likes and comments, but a question arose. If I like or comment on another user's post, how do I notify them? So that, for example, there would be a counter above the "Notifications" link. You must have understood me. I mean, something like "My answers" in VK. Please tell me how to develop it? Or tell me what is better to read. Perhaps someone has done something like this.
I apologize if I didn't express myself very clearly.

Answer 1

Do you mean the structure of the database?
If so, here is an example:
-users
id, first_name, last_name, email, created
-articles
id, user_id, title, descr, created
- article_comments
id, comment_id, user_id, text, created
- article_comment_views
id, comment_id, user_id, created
If, for example, the author of the article has not read the comment, there will be no entry in the article_comment_views table, respectively, this is a new event, you can notify the user
. You can also just trite when adding a new comment, add a new event for the user to some news table.

Answer 2

Already been How to add an alert from the site administrator?