The regenerate database is only necessary after a parts update. It got mentioned lately because someone was manually updating the parts repository (because their auto update was broken) and they need to manually do that after the new repository is cloned (automatic parts update does it as part of the install.) So you can usually ignore it.
I prefer to ignore parts editor and edit the files directly. For some things (bendable leg parts for one) that is the only way to do it as parts editor doesn’t currently support it. Parts editor was not finished when development stopped so it is not complete, but many find it easiest.
Currently that isn’t easy. At present the user directory files are hard coded so all Fritzing versions will use the same files and may cause corruption. I’m poking at changing the code to allow changing the file location via a command line flag (mostly for testing new Fritzing versions) but it isn’t currently ready. I use one version of Fritzing and make sure I have backup copies of all the .fzz and .fzpz files outside of Fritzing (so I can clear the user directories if necessary.)
My typical path is described here:
Peter