title strange behavior on windows 10

Hello!

I used digikam from 7.0. I found a strange behavior on windows 10 with 
the 8.0+

I set up the metadata storage both in file, and database.

After I let the digikam just running over some time (overnight, maybe 
more than 2 hours), it forgot the title (sometimes the tags too) of the 
images.

It shows nothing. But the information is in the image file. And If I 
change something to force write out all date, it delete the missing 
information from the image too.


I'd like to create a simple backup script (copy the information between 
two database), I'd like some information of the database: where are the 
title of the image stored?

Thanx

Csaba