Get variable name from abap report

Hello

I have the next scenario:

- i have a GUI structure that contains some fields. These fields have to be saved in the db, but the data elements in the table have different names.Therefore i have to do a mapping between the gui field and the db field. For this i need the variable name from the gui in order to search for the gui field in the table . This has to be done dynamically.

For ex:

i need a method that does the next:

data: ls_matnr type mara.

call method obj->get_var_name(

          exporting

               field = ls_mara-matnr

          importing

               name = lv_var           )

write lv_result.

Result should be in this case "LS_MARA-MATNR"

Thank you