How to update a TableView in QML?

I am coding a program combining QML and C++. The TableView shows a column of a table. I can add or delete the record correctly, but I can not update the TableView, which always shows the content before adding or deleting.

How to update the TableView?

PS: I do not know whether it is good choice to code with QML and C++ instead of QWidget directly. At least by now, it keeps frustrating me.