How to make sure that the buyer does not see the data on the site (apartment number, announcement date, seller's full name and phone number) do you need to include a hierarchy in the database?

Question

MySQL

ps hierarchy is the seller, the buyer and the admin
ps I'm making a site like cyan

Answer 1

ps hierarchy is seller buyer and admin

This is not a hierarchy, these are user roles.
You should define the user's role, then display information depending on his role.