The OWASP Postgres hardening page recommends that one removes the default "public" schema in postgres: https://www.owasp.org/index.php/OWASP_Backend_Security_Proje...

...whereas this course seems to use the public schema and just query for "SELECT * IN public.foobar" etc.

I remember being a bit confused about "schemas" when I switched from mysql to postgres. I think it would be good to have a special section that explains what schemas are typically used for, and in particular when/how to use the public schema correctly.