If you dig deep into my program, you can automatically submit the SQL update, when you change tabs, if an md5sum change was detected in the fields. No need to have a Save Changes button.(This avoids lost changes if you accidently switch tabs :-) ) Do your automatic magic in the "raisecmd" and "lowercmd" callbacks of the Notebook widgets. But you are probably starting to figure this out. :-)

FWIW, Tk the Tk Text widget dosn't have a "is_edited" flag, so you need to rely on md5sums, or something similar. However, Gtk2 does has an "has_been_edited" signal.