Why can't I block access to a specific file?

Question

Apache HTTP Server

The people, on a server (not mine), there is a folder - modules. There is an .htaccess file with the following content
: Order Deny, Allow
Deny from all
In short, this directive blocks the entire folder for me for requests.
But I specifically need to allow access to some folder, and inside it there is a db folder, which I need to deny access to, since there is a kind of database there.
Tell me how to do it?
I perverted in different ways, but the basic knowledge is not enough all the time to catch the desired configuration
Thank you in advance.

modules - prohibition, except for the calc folder
---calc - allow everything here, except for the db folder, inside which there is 1 file and it must be prohibited
------db

Answer 1

/modules/.htaccess /modules/calc/.htaccess /modules/calc/db/.htaccess
Deny from all