you can filter for any known field with
%fieldname% PRESENT
You can also get an overview which tag fields are in your collection like this:
Load all your files
Select all your files
Press Alt-T to open the extended tags dialogue.
In this dialogue you see all fields that are present in any file.
It would then be a good way to filter for these fields and see which files actually contain them. as probably not all files will feature the more exotic fields.
As far as I see it these actions replace a DB with dB.
And if there is no such field, then no replacing should be possible.