Voice memos - Recordings.db not updated on iOS 7.1.2
OK I've figured it out, thanks to this page.

If I understand correctly, the Recordings.db file is just the "structure" of the SQLite database. The transactions are stored in another file called "Recordings.db-wal".

Quote : "WAL files are a form of cache whereby data that is written to an SQLite db is first written to the WAL file (when this is enabled) and then at a later time (known as a checkpoint) the SQLite data is written into the main database".

So in order to view the data, Recordings.db and Recordings.db-wal needs to be in the same directory before opening Recordings.db with a SQLite DB viewer.