What is the best way to implement the city system?

Question

Database design

It was necessary to add cities, as I understand it, the only option is to add a city_id column to each table
. Well, or city_name.
Is it a good idea to make {city_name}.domain.com to group data by city?

Answer 1

Normal

Answer 2

There are identical cities in different countries, what will happen in this case in terms of the domain?