ABAP Select data from SAP table KCDS_STRUC into internal table

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Below is a number of ABAP code snippets to demonstrate how to select data from SAP KCDS_STRUC table and store it within an internal table, including using the newer @DATA inline declaration methods. It also shows you various ways to process this data using ABAP work area, inline declaration or field symbols including executing all the relevant CONVERSION_EXIT routines specific to KCDS_STRUC. See here for more generic Select statement tips.

Sometimes data within SAP is stored within the database table in a different format to what it is displayed to the user. These input/output conversation FM routines are what translates the data between the two formats.

There is also a full declaration of the KCDS_STRUC table where each field has a char/string type for you to simply copy and paste. This allows you to use processing that is only available to these field types such as the CONCATENATE statement.

DATA: IT_KCDS_STRUC TYPE STANDARD TABLE OF KCDS_STRUC,
      WA_KCDS_STRUC TYPE KCDS_STRUC,
      GD_STR TYPE STRING.

DATA: lo_typedescr type REF TO cl_abap_typedescr.
DATA: lv_fieldname type fieldname.

FIELD-SYMBOLS: <FIELD> TYPE any.
FIELD-SYMBOLS: <KCDS_STRUC> TYPE KCDS_STRUC.

*Process all fields in table header/work area as string values
  PERFORM process_as_string_field_values CHANGING wa_KCDS_STRUC.

SELECT *
*restrict ABAP select to first 10 rows
 UP TO 10 ROWS      
  FROM KCDS_STRUC
  INTO TABLE IT_KCDS_STRUC.

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM KCDS_STRUC
*  INTO TABLE @DATA(IT_KCDS_STRUC2).
*--Further methods of using ABAP code to  select data from SAP database tables

*You can also declare the header/work area using the in-line DATA declaration method
READ TABLE IT_KCDS_STRUC INDEX 1 INTO DATA(WA_KCDS_STRUC2).


*Demonstrate how to loop at an internal table and update values using a FIELD-SYMBOL
LOOP AT IT_KCDS_STRUC ASSIGNING <KCDS_STRUC>.

*To update a field value using a field symbol simply change the value via the field symbol pointer
<KCDS_STRUC>-SFELD = 1.
<KCDS_STRUC>-TNAME = 1.
<KCDS_STRUC>-POSIT = 1.
<KCDS_STRUC>-ITYPE = 1.
<KCDS_STRUC>-DTYPE = 1.

ENDLOOP.

LOOP AT IT_KCDS_STRUC INTO WA_KCDS_STRUC.
*Write horizonal line to screen report.
  WRITE:/ sy-uline.

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_KCDS_STRUC-ILENG, sy-vline,
  WA_KCDS_STRUC-DECIM, sy-vline,
  WA_KCDS_STRUC-RFTAB, sy-vline,
  WA_KCDS_STRUC-RFFIE, sy-vline,
  WA_KCDS_STRUC-ROLNM, sy-vline,
  WA_KCDS_STRUC-FTEXT, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_KCDS_STRUC you want to display...

  WRITE:/ sy-uline.
* Aternatively use generic code to Write field values (and NAME) to screen report
  DO.
    ASSIGN COMPONENT sy-index OF STRUCTURE wa_KCDS_STRUC TO <field>.
    IF sy-subrc <> 0. EXIT. ENDIF.
    WRITE:/ 'Field Value', <field>, sy-vline.
    gd_str = <field> .
    lo_typedescr ?= CL_ABAP_DATADESCR=>DESCRIBE_BY_DATA( <field> ).
    lv_fieldname = lo_typedescr->GET_RELATIVE_NAME( ).
    WRITE:/ 'Field Name', lv_fieldname.
  ENDDO.

  
*Redo loop but convert all fields from internal to out value  
LOOP AT IT_KCDS_STRUC INTO WA_KCDS_STRUC.


*Write horizonal line to screen report.
  WRITE:/ sy-uline.

*Convert all fields to display/output versions using conversion routines
  PERFORM convert_all_field_values CHANGING wa_EKKO.
	 
ENDLOOP.

  
*&---------------------------------------------------------------------*
*& Form convert_all_field_values
*&---------------------------------------------------------------------*
FORM convert_all_field_values CHANGING p_EKKO LIKE wa_EKKO.
DATA: ld_input(1000) TYPE c, ld_output(1000) TYPE C.

*Conversion exit DTYPE, internal->external for field DTYPE
CALL FUNCTION 'CONVERSION_EXIT_DTYPE_OUTPUT'
  EXPORTING
    input =                      WA_KCDS_STRUC-DTYPE
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_KCDS_STRUC-DTYPE.
WRITE:/ 'New Value:', ld_input.
ENDFORM. 

*&---------------------------------------------------------------------*
*& Form process_as_string_field_values
*&---------------------------------------------------------------------*
FORM process_as_string_field_values CHANGING p_EKKO LIKE wa_EKKO.

TYPES: BEGIN OF T_KCDS_STRUC_STR, 
SFELD TYPE STRING,
TNAME TYPE STRING,
POSIT TYPE STRING,
ITYPE TYPE STRING,
DTYPE TYPE STRING,
ILENG TYPE STRING,
DECIM TYPE STRING,
RFTAB TYPE STRING,
RFFIE TYPE STRING,
ROLNM TYPE STRING,
FTEXT TYPE STRING,
LOWCS TYPE STRING,END OF T_EKKO_STR.
DATA: WA_KCDS_STRUC_STR type T_EKKO_STR.

DATA: ld_text TYPE string.

LOOP AT IT_EKKO INTO WA_EKKO.
  MOVE-CORRESPONDING wa_EKKO TO WA_EKKO_STR.
  CONCATENATE: sy-vline
WA_KCDS_STRUC_STR-SFELD sy-vline 
WA_KCDS_STRUC_STR-TNAME sy-vline 
WA_KCDS_STRUC_STR-POSIT sy-vline 
WA_KCDS_STRUC_STR-ITYPE sy-vline 
WA_KCDS_STRUC_STR-DTYPE sy-vline 
WA_KCDS_STRUC_STR-ILENG sy-vline 
WA_KCDS_STRUC_STR-DECIM sy-vline 
WA_KCDS_STRUC_STR-RFTAB sy-vline 
WA_KCDS_STRUC_STR-RFFIE sy-vline 
WA_KCDS_STRUC_STR-ROLNM sy-vline 
WA_KCDS_STRUC_STR-FTEXT sy-vline 
WA_KCDS_STRUC_STR-LOWCS sy-vline      INTO ld_text SEPARATED BY SPACE.

*Add any further fields from structure WA_EKKO_STR you want to CONCATENATE...
ENDLOOP.
ENDFORM.