ABAP Select data from SAP table LIST_DSF into internal table

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Below is a number of ABAP code snippets to demonstrate how to select data from SAP LIST_DSF 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 LIST_DSF. 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 LIST_DSF 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_LIST_DSF TYPE STANDARD TABLE OF LIST_DSF,
      WA_LIST_DSF TYPE LIST_DSF,
      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: <LIST_DSF> TYPE LIST_DSF.

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

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

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM LIST_DSF
*  INTO TABLE @DATA(IT_LIST_DSF2).
*--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_LIST_DSF INDEX 1 INTO DATA(WA_LIST_DSF2).


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

*To update a field value using a field symbol simply change the value via the field symbol pointer
<LIST_DSF>-TABNAME = 1.
<LIST_DSF>-FIELDNAME = 1.
<LIST_DSF>-AS4LOCAL = 1.
<LIST_DSF>-TEXT = 1.
<LIST_DSF>-TEXT2X = 1.

ENDLOOP.

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

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_LIST_DSF-DEVCLASS, sy-vline,
  WA_LIST_DSF-AS4USER, sy-vline,
  WA_LIST_DSF-AS4DATE, sy-vline,
  WA_LIST_DSF-TABCLASS, sy-vline,
  WA_LIST_DSF-POSITION, sy-vline,
  WA_LIST_DSF-PRECFIELD, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_LIST_DSF 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_LIST_DSF 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_LIST_DSF INTO WA_LIST_DSF.


*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 DATATYPE
CALL FUNCTION 'CONVERSION_EXIT_DTYPE_OUTPUT'
  EXPORTING
    input =                      WA_LIST_DSF-DATATYPE
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_LIST_DSF-DATATYPE.
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_LIST_DSF_STR, 
TABNAME TYPE STRING,
FIELDNAME TYPE STRING,
AS4LOCAL TYPE STRING,
TEXT TYPE STRING,
TEXT2X TYPE STRING,
DEVCLASS TYPE STRING,
AS4USER TYPE STRING,
AS4DATE TYPE STRING,
TABCLASS TYPE STRING,
POSITION TYPE STRING,
PRECFIELD TYPE STRING,
ROLLNAME TYPE STRING,
DOMNAME TYPE STRING,
LOGFLAG TYPE STRING,
MEMORYID TYPE STRING,
KEYFLAG TYPE STRING,
CHECKTABLE TYPE STRING,
VALEXI TYPE STRING,
REFTABLE TYPE STRING,
REFFIELD TYPE STRING,
DATATYPE TYPE STRING,
LENG TYPE STRING,
OUTPUTLEN TYPE STRING,
LOWERCASE TYPE STRING,
DECIMALS TYPE STRING,
SIGNFLAG TYPE STRING,
REPTEXT TYPE STRING,
SCRTEXT_S TYPE STRING,
SCRTEXT_M TYPE STRING,
SCRTEXT_L TYPE STRING,END OF T_EKKO_STR.
DATA: WA_LIST_DSF_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_LIST_DSF_STR-TABNAME sy-vline 
WA_LIST_DSF_STR-FIELDNAME sy-vline 
WA_LIST_DSF_STR-AS4LOCAL sy-vline 
WA_LIST_DSF_STR-TEXT sy-vline 
WA_LIST_DSF_STR-TEXT2X sy-vline 
WA_LIST_DSF_STR-DEVCLASS sy-vline 
WA_LIST_DSF_STR-AS4USER sy-vline 
WA_LIST_DSF_STR-AS4DATE sy-vline 
WA_LIST_DSF_STR-TABCLASS sy-vline 
WA_LIST_DSF_STR-POSITION sy-vline 
WA_LIST_DSF_STR-PRECFIELD sy-vline 
WA_LIST_DSF_STR-ROLLNAME sy-vline 
WA_LIST_DSF_STR-DOMNAME sy-vline 
WA_LIST_DSF_STR-LOGFLAG sy-vline 
WA_LIST_DSF_STR-MEMORYID sy-vline 
WA_LIST_DSF_STR-KEYFLAG sy-vline 
WA_LIST_DSF_STR-CHECKTABLE sy-vline 
WA_LIST_DSF_STR-VALEXI sy-vline 
WA_LIST_DSF_STR-REFTABLE sy-vline 
WA_LIST_DSF_STR-REFFIELD sy-vline 
WA_LIST_DSF_STR-DATATYPE sy-vline 
WA_LIST_DSF_STR-LENG sy-vline 
WA_LIST_DSF_STR-OUTPUTLEN sy-vline 
WA_LIST_DSF_STR-LOWERCASE sy-vline 
WA_LIST_DSF_STR-DECIMALS sy-vline 
WA_LIST_DSF_STR-SIGNFLAG sy-vline 
WA_LIST_DSF_STR-REPTEXT sy-vline 
WA_LIST_DSF_STR-SCRTEXT_S sy-vline 
WA_LIST_DSF_STR-SCRTEXT_M sy-vline 
WA_LIST_DSF_STR-SCRTEXT_L sy-vline      INTO ld_text SEPARATED BY SPACE.

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