Private variable name could be more informative

It is a bit confusing to have a class called Database with an internal database variable:

https://gitlab.idiap.ch/bob/bob.db.drive/blob/master/bob/db/drive/query.py#L37

Maybe you could think of a different name? filelist or something of the sorts would make it more obvious. If this variable is supposed to be private, you could name it _filelist instead. It is a widely accepted standard for "class-privacy" inside Python.