When you want to upload PC file to internal table in ABAP/4, you can apply function module "WS_UPLOAD".

Example

  call function ’WS_UPLOAD’
       exporting
            filename                = lv_name
            filetype                = lv_type
       tables
            data_tab                = li_tab
       exceptions
            file_open_error         = 1
            file_read_error         = 2
            no_batch                = 3
            gui_refuse_filetransfer = 4
            others                  = 5.