MySQL Connection URL - Host is the name of the docker-compose service for the database or localhost?

[Nsandomeno]

In your .env.example you still have the postgresql connection URL, and the is localhost... I was wondering if your actual MySQL connection URL is using localhost as the of the name of the docker-compose database service: "db"

With this as a base: "mysql//:< username >:< password >@< host >/< dbname >" ...

I am asking if you are actually using:

(a) "mysql//:< username >:< password >@db/< dbname >"

or

(b) "mysql//:< username >:< password >@localhost/< dbname >"