Editable Alv update database table

gistfile1.xslt

REPORT ZBC0818_EDITABLEALV_ALINAN.
* Data declarations
DATA : itab             TYPE STANDARD TABLE OF  'Database Table Name',"Output table
       i_fieldcat       TYPE STANDARD TABLE OF  lvc_s_fcat,"Field catalog
       i_modified       TYPE STANDARD TABLE OF  'Database Table Name',"For getting modified rows
       i_selected_rows  TYPE                    lvc_t_row,"Selected Rows
       w_selected_rows  TYPE                    lvc_s_row,
       w_modified       TYPE                    'Database Table Name',
       wa               TYPE                    'Database Table Name',
       w_variant        TYPE                    disvariant,
       o_docking        TYPE REF TO             cl_gui_docking_container,"Docking Container
       o_grid           TYPE REF TO             cl_gui_alv_grid."Grid

data : fs_fieldcat TYPE lvc_s_fcat.

SELECT * FROM 'Database Table Name' INTO TABLE itab .
CALL SCREEN 9000.

*&---------------------------------------------------------------------*
*&      Module  STATUS_9000  OUTPUT
*&---------------------------------------------------------------------*
*       PBO
*----------------------------------------------------------------------*

MODULE status_9000 OUTPUT.
  IF o_docking IS INITIAL.
    SET PF-STATUS 'STATUS_9000'. "GUI Status
    SET TITLEBAR 'ZTITLE'.   "Title
* Creating Docking Container and grid
    PERFORM create_object.
* Filling the fieldcatalog table
    PERFORM create_fieldcat.
* Modifying the fieldcatalog table
    PERFORM modify_fieldcat.
* Registering edit
    PERFORM register_edit.
* Displaying the output
    PERFORM display_output.
  ENDIF.

ENDMODULE.                 " STATUS_9000  OUTPUT

*&---------------------------------------------------------------------*
*&      Module  USER_COMMAND_9000  INPUT
*&---------------------------------------------------------------------*
*       PAI
*----------------------------------------------------------------------*

MODULE user_command_9000 INPUT.
  DATA lv_ucomm TYPE sy-ucomm.
  lv_ucomm = sy-ucomm.
  CASE lv_ucomm.
    WHEN 'UP'.
      PERFORM free_objects.
      SET SCREEN 0.
      LEAVE SCREEN.
    WHEN 'EXIT'.
      PERFORM free_objects.
      LEAVE PROGRAM.
    WHEN 'BACK'.
      PERFORM free_objects.
      SET SCREEN '0'.
      LEAVE SCREEN.
    WHEN 'SAVE'.
      PERFORM save_database.
      CALL METHOD o_grid->refresh_table_display.
  ENDCASE.

ENDMODULE.                 " USER_COMMAND_9000  INPUT

*&---------------------------------------------------------------------*
*&      Form  create_object
*&---------------------------------------------------------------------*
*       Creating Docking Container and grid
*----------------------------------------------------------------------*

FORM create_object .
* Creating Docking Container
  CREATE OBJECT o_docking
         EXPORTING   ratio = '95'.

  IF sy-subrc EQ 0.
* Creating Grid
    CREATE OBJECT o_grid
        EXPORTING i_parent = o_docking.
  ENDIF.

ENDFORM.                    " create_object

*&---------------------------------------------------------------------*
*&      Form  create_fieldcat
*&---------------------------------------------------------------------*
*       Filling the fieldcatalog table
*----------------------------------------------------------------------*

FORM create_fieldcat .
* Filling the fieldcatalog table
  CALL FUNCTION 'LVC_FIELDCATALOG_MERGE'
    EXPORTING i_structure_name   = '"Database Table Name"'
    CHANGING ct_fieldcat         = i_fieldcat
    EXCEPTIONS
      inconsistent_interface = 1
      program_error          = 2
      OTHERS                 = 3.
ENDFORM.                    " create_fieldcat

*&---------------------------------------------------------------------*
*&      Form  modify_fieldcat
*&---------------------------------------------------------------------*
*       Making the column as ediable
*----------------------------------------------------------------------*

FORM modify_fieldcat .
  LOOP AT i_fieldcat into fs_fieldcat .
    CASE fs_fieldcat-fieldname.
      WHEN '"write here Fieldname"'.
        fs_fieldcat-coltext = 'write here text you want to see as header on the list' .
        MODIFY i_fieldcat FROM fs_fieldcat.

    WHEN '"write here fieldname"'.
* Making a column as Editable
        fs_fieldcat-coltext = 'write here text you want to see as header on the list' .
        fs_fieldcat-edit = 'X'.
        MODIFY i_fieldcat FROM fs_fieldcat.

    WHEN 'write here fieldname'.
        fs_fieldcat-coltext = 'write here text you want to see as header on the list' .
        MODIFY i_fieldcat FROM fs_fieldcat.
    ENDCASE.
  ENDLOOP.
ENDFORM.                    " modify_fieldcat

*&---------------------------------------------------------------------*
*&      Form  register_edit
*&---------------------------------------------------------------------*
*       Registering Edit
*----------------------------------------------------------------------*

FORM register_edit .
  CALL METHOD o_grid->register_edit_event
    EXPORTING  i_event_id = cl_gui_alv_grid=>mc_evt_modified.
ENDFORM.                    " register_edit

*&---------------------------------------------------------------------*
*&      Form  display_output
*&---------------------------------------------------------------------*
*       Displaying the output
*----------------------------------------------------------------------*

FORM display_output .
  w_variant-report = sy-repid.
* Displaying the output
  CALL METHOD o_grid->set_table_for_first_display
    EXPORTING
      is_variant                    = w_variant
      i_save                        = 'A'
    CHANGING
      it_outtab                     = itab
      it_fieldcatalog               = i_fieldcat
    EXCEPTIONS
      invalid_parameter_combination = 1
      program_error                 = 2
      too_many_lines                = 3
      OTHERS                        = 4.

  CALL METHOD o_grid->register_edit_event
    EXPORTING i_event_id = cl_gui_alv_grid=>mc_evt_modified.

  IF sy-subrc <> 0.
    MESSAGE ID sy-msgid TYPE sy-msgty NUMBER sy-msgno
                WITH sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4.
  ENDIF.

ENDFORM.                    " display_output

*&---------------------------------------------------------------------*
*&      Form  free_objects
*&---------------------------------------------------------------------*
*       Free Objects
*----------------------------------------------------------------------*

FORM free_objects .
  CALL METHOD o_grid->free
    EXCEPTIONS
      cntl_error        = 1
      cntl_system_error = 2
      OTHERS            = 3.
  IF sy-subrc <> 0.
    MESSAGE ID sy-msgid TYPE sy-msgty NUMBER sy-msgno
               WITH sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4.
  ENDIF.

  CALL METHOD o_docking->free
    EXCEPTIONS
      cntl_error        = 1
      cntl_system_error = 2
      OTHERS            = 3.
  IF sy-subrc <> 0.
    MESSAGE ID sy-msgid TYPE sy-msgty NUMBER sy-msgno
               WITH sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4.
  ENDIF.

ENDFORM.                    " free_objects

*&---------------------------------------------------------------------*
*&      Form  save_database
*&---------------------------------------------------------------------*
*       Save in database
*----------------------------------------------------------------------*

FORM save_database.
* Getting the selected rows index
  CALL METHOD o_grid->get_selected_rows
    IMPORTING  et_index_rows = i_selected_rows.
* Through the index capturing the values of selected rows
  LOOP AT i_selected_rows INTO w_selected_rows.
    READ TABLE itab INTO wa INDEX w_selected_rows-index.
    IF sy-subrc EQ 0.
      MOVE-CORRESPONDING wa TO w_modified.
      APPEND w_modified TO i_modified.
    ENDIF.
  ENDLOOP.
  MODIFY 'database table name' FROM TABLE i_modified.
ENDFORM.                    " save_database

how to save the drop down values of alv in a customise table in abap??