Sync tag between main/backup database

Yep 2 all !

2 databases, one is my working database (on a external memory), the other my backup.
I use soft like Rekordbox, Traktor. So the tags are constantly changing...
I was looking for a solution to keep all the databases synced :book: and I discover this:

Way To Display Tag Differences Between Same Filenames in 2 Folders?

If I understand, I have to create a same folder structure, use the same file's name and that's it?
Can I limit on particular tags only? like %ratings mm%, ...

Thanks by advance !
and thanks for mp3tag, this is a really nice tools

If you look for a fairly cheap, reliable and flexible synchronizing tool that only transfers the files that have changed, have a look at the Microsoft Synctoy.

Although I hold Mp3tag in high esteem I do not see it as real help for synchronizing.

The Synctoy synchronizes folders with all their subfolders.

Mp3tag is an application, which can tag media files, create reports and something more.
There is no database included and there is no support for external databases.
If you are at odds with two databases, how should Mp3tag intervene?

You referred to a forum post, which offers a proposal, how someone can help himself to keep two sets of tagged files in sync by using the tools offered by Mp3tag. You have to follow the proposal's sense and its tasklist.