Thanks. I'll give it a try. I chose MySQL because I knew there were Python libraries I could use.
The SQLite libraries seem to be built into Python, so nothing extra to add:
https://docs.python.org/2/library/sqlite3.html
https://docs.python.org/3/library/sqlite3.html
And the PostgreSQL equivalent:
Hmmm, there seem to be several PostgreSQL Python libraries around, all in active development.
You'll probably be fine with SQLite though. :)