I have database files, boss_db.zip.part1, boss_db.zip.part2 and boss_db.zip.part3.
In what way do you think they are database files?
I would have speculated that there was/is a database boss or boss_db and some external representation of it has been zipped up into three files.
The question is what is the external representation.
Is it the database files? If so are they the right ones.
Is it sql statements representing a dump of the database?