django.db.utils.OperationalError: (2002, Can't connect to MySQL server on 'db' code example

Example: django.db.utils.OperationalError: (2002, “Can't connect to MySQL server on 'db'

# Make sure that your db docker image is running fine. Check the logs of the running db container. 
# I am able to use MariaDB successfully in my docker-compose file :

db:
image: mariadb
ports:
  - 3306:3306
environment:
  MYSQL_USER: "****"
  MYSQL_PASSWORD: "****"
  MYSQL_DATABASE: "*****"
  MYSQL_RANDOM_ROOT_PASSWORD: "yes"