Real-time data is not retrieved from the database. It comes directly from device communication back-end using long-polling.
For more details see async servlet implementation:
https://github.com/tananaev/traccar/blob/master/src/org/traccar/http/AsyncServlet.java
I would like to use this software's frontend and manually update the database via MySQL INSERTs. I was able to add in my first site using fake data, but when I try to update the position, the dot on the map doesn't move. The Report is the only way for me to see updated positions.