There are a number of tools, e.g.:
http://sqlitebrowser.org/
Annotation export is a weakness of most reading apps. One exception is Google's Play Books app, which will save them to a Google doc, which you can view or export as you wish (you can edit directly but it creates a new doc each time you create a new annotation so your changes would get overwritten). You can also import your own ePub files and it works with those as well.
One strategy is to use iOS sharing (to something like Evernote, OneNote, Apple Notes etc.). It is extra work (essentially these are independent of Kobo annotations so you potentially have to duplicate effort), but probably more convenient than messing with SQLLite database.