NFO / XML import update?

I am using Sqliteman to fool around with a local copy of my videodb, and noticed a few things when comparing against the example NFO:
-is the “credits” field in the example used for the writer(s)?
-why is there a <filenameandpath> tag in the NFO XML? Wouldn’t this value be found during scanning (because the NFO file will be alongside the media it refers to?) just seemed redundant to me…
-The “studio” field from the database is not included in the example NFO. Is it possible to store this value in the NFO files?