How to check the correct entered city?

Question

Yii

There are two tables: applications and cities.
How can I check when creating an application whether there is a city id in the database entered when creating an application? It is necessary to highlight an error in the absence of a city in the database. The problem I had was that the id of the cities is in another table and I had difficulties with this.

Answer 1

use ExistValidator for this purpose