Database-wise, I'm not sure what you're asking. Could you elaborate?
As far as export/import, you can export your notes as .rtf to be used, edited, or integrated with external programs.
I expect a prog like this to have import/export options for text etc.
The database issue is a big one. It doesn't really matter for text/notes because there are lots of ways of dealing with that. It does matter for info that you would never want to retype and where you want certainty of future access to the data all in the right fields. It is one of the main things I look at for any database prog. It is never possible to predict which progs will come to an end and there is always the risk of being left high and dry; much less likely for very popular progs because someone will be likely to produce a means of moving the data to a still current prog.
Many progs are founded on a mainstream database engine rather than their own in-program option. For instance IdImager has options based on SQLite and SQLserver (and used to have an option based on Access's Jet engine). This gives extra confidence that the data will be readable & managable in in the future. If this is the case, it is nice to know what the engine is (and will give an idea of strengths, weaknesses and scalability).
Whether this is true or not, it is reassuring to be able to export the database in a format that can be read by other progs. Just as an way of avoiding the data being left up a blind alley.
The info in NoteScribe that seems to require that protection is the citations/sources, and probably the linkage between text, sources and attachments.
All the progs I rely on a lot have the ability to export their databases in fairly common formats. Otherwise I would never have considered them.