How can I restore the persistent data for Mac's native Stickies app?

I use the native Stickies app a lot. I've been using it on this Mac for like 5 years. I don't know why, but when I upgraded to the latest MacOS (to 10.15.2, from whatever was the big release before it), all my sticky notes disappeared. It was like none had ever existed. It appears that data isn't actually lost. The web tells me Stickies stores that data in a file at ~/Library/StickiesDatabase. That file exists, and both TextEdit and bash strings reveal that my note data is in there. It's embedded in an illegible binary file, whose format I know nothing about. I have way too many notes for it to be practical to manually copy-and-paste from that format, and I'm not even sure I can read it properly myself. Maybe if I could read it using bash or node, but I don't know anything about the file format. Anyway, for whatever reason, when I run the Stickies app, it doesn't show that data in any of its notes. Simply putting the file in the location expected by the app is not sufficient, evidently. I don't know what is lacking, though. I tried Stickies' File > Import Text, but that just loaded the raw binary format for all my old notes into a single new note, instead of really grokking the database and restoring the notes inside. After closing and re-opening Stickies with that one crazy one, _all_ my notes were gone again. (I kept a backup of the original file.) Is there any way to restore the data in that file? It's already in the proper location, and I certainly haven't hand edited. Or failing that, are there any good tools for parsing it?