Fill arbitrary column in dynamic itab?

Question

I am currently trying to create a report with a dynamically created internal table (the number of columns can be different every time). Is there a way how I can address the generated columns while filling the structure of the given table?

Here is the code I am working with:

FIELD-SYMBOLS: <fcat>         TYPE lvc_s_fcat,
              <fcat_aus>     TYPE ANY TABLE.

   IF so_datum-high <> ''.
     DATA(lv_month_diff) = so_datum-high - so_datum-low.
   ELSE.
     DATA(lv_month) = so_datum-low.
   ENDIF.

   APPEND INITIAL LINE TO gt_fcat ASSIGNING <fcat>.
   <fcat>-fieldname = 'MATNR'.
   <fcat>-tabname   = 'GZ_TABLE'.
   <fcat>-ref_field = 'MATNR'.
   <fcat>-ref_table = 'MAKT'.

   APPEND INITIAL LINE TO gt_fcat ASSIGNING <fcat>.
   <fcat>-fieldname = 'MAKTX'.
   <fcat>-tabname   = 'GZ_TABLE'.
   <fcat>-ref_field = 'MAKTX'.
   <fcat>-ref_table = 'MAKT'.

   DATA(lv_counter) = 1.

   DO 10 TIMES.
     DATA(lv_fieldname_qt)  = 'MOQ' &&  lv_counter.
     DATA(lv_fieldname_fqt) = 'MFQ' &&  lv_counter.

     lv_counter = lv_counter + 1.

     APPEND INITIAL LINE TO gt_fcat ASSIGNING <fcat>.
     <fcat>-fieldname = lv_fieldname_qt.
     <fcat>-tabname   = 'GZ_TABLE'.
     <fcat>-ref_field = 'MNG01'.
     <fcat>-ref_table = 'MDEZ'.

     APPEND INITIAL LINE TO gt_fcat ASSIGNING <fcat>.
     <fcat>-fieldname = lv_fieldname_fqt.
     <fcat>-tabname   = 'GZ_TABLE'.
     <fcat>-ref_field = 'MNG01'.
     <fcat>-ref_table = 'MDEZ'.

   ENDDO.

 CALL METHOD cl_alv_table_create=>create_dynamic_table
   EXPORTING
     it_fieldcatalog           = gt_fcat
   IMPORTING
     ep_table                  = gz_table
   EXCEPTIONS
     generate_subpool_dir_full = 1
     OTHERS                    = 2.

 ASSIGN gz_table->* to <fcat_aus>. 

Maybe one of you has an idea. Thanks in advance!

Answer 1

Use the ASSIGN COMPONENT statement to access a structure component dynamically. Check the ABAP documentation (F1) for further details. You can specify the component by index or by field name.

Answer 2

Here is an example to complete Thomas answer (note that I don't explain how to create a table dynamically with CREATE DATA as it's not your question, here it's created statically with 2 components, I only explain how to fill an internal table by referring to it dynamically):

TYPES: BEGIN OF ty_line,
         comp1 TYPE i,
         text_component TYPE string,
       END OF ty_line,
       ty_itab TYPE STANDARD TABLE OF ty_line WITH DEFAULT KEY.
DATA r_itab TYPE REF TO DATA.
DATA r_line TYPE REF TO DATA.
FIELD-SYMBOLS <itab> TYPE STANDARD TABLE.
FIELD-SYMBOLS <line> TYPE ANY.
FIELD-SYMBOLS <component> TYPE ANY.

" create an internal table, here it's the static way, but you may also use CREATE DATA 
" to create it dynamically
CREATE DATA r_itab TYPE ty_itab.
ASSIGN r_itab->* TO <itab>.

" now let's fill it dynamically, first define a line
CREATE DATA r_line LIKE LINE OF <itab>.
ASSIGN r_line->* TO <line>.
ASSIGN COMPONENT 1 OF <line> TO <component>. " access to COMP1 component
IF sy-subrc = 0.
  <component> = 30.
ENDIF.
ASSIGN COMPONENT 'TEXT_COMPONENT' OF <line> TO <component>.
IF sy-subrc = 0.
  <component> = 'text'.
ENDIF.

" now add the line
INSERT <line> INTO TABLE <itab>.

Note that it's possible to access the whole line with ASSIGN COMPONENT 0 ... (especially useful if the internal table has none component).

More information:

• ASSIGN
• ->* (dereferencing operator)
• CREATE DATA