How can I trigger data_changed in ALV Grid ?

I'm using ALV Grid of cl_gui_alv_grid class, and already registerd data_changed event.

I use two functioning :

1) when F4 Help clicked on <b>editable key fields</b>

--> delete the row and insert new row

2) when user command in ALV Grid toolbar clicked on <b>editable key fields</b>

--> insert new row

Q1. After key fields are edited, I want to delete & insert the changed data to the corresponding DB table when save button clicked.

Q2. In case 2), Is there any way to make data_changed event triggered after user command event?