Auto apply a formula to a table

Auto apply a formula to a table

Is it possible to bulk edit a table using a formula?  

The following formula is currently in the form actions on user input:


if (input.devices_room  !=  null)
{
    roomid = Locations[ID = input.devices_room].locations_room_ref;
    input.device_ash_code = roomid + "/";
}

I want to amend the bulk edit existing records and then delete the bulk edit formula rather than go in and edit each record