method private _vtable_gui_answer = fun input ->
try
SQL_db.link_vtable_to_db (Dbf_misc.unopt input.VTGUI.vtgi_vtable);
vtable_model#append_data (Dbf_misc.unopt input.VTGUI.vtgi_vtable)
with
| SQL_db.Duplicated_name name ->
raise (Invalid_input "Name already used")