Something like this should work... I use the NI DB Toolkit and an Oracle database to write to the blob using parameterized queries (you can't write binary data using pure string queries). Maybe with SQLite you have something similar.
@igorbounov I haven't worked with SQLite for blobs, but had some experience with the NI Database Toolkit. I had to flatten data to a string and then convert the string to a U8 byte array before being able to save it correctly. Maybe that helps