ABAP Select data from SAP table DDENTITY_COLUMN into internal table

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

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

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

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM DDENTITY_COLUMN
*  INTO TABLE @DATA(IT_DDENTITY_COLUMN2).
*--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_DDENTITY_COLUMN INDEX 1 INTO DATA(WA_DDENTITY_COLUMN2).


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

*To update a field value using a field symbol simply change the value via the field symbol pointer
<DDENTITY_COLUMN>-ENTITYNAME = 1.
<DDENTITY_COLUMN>-FIELDNAME = 1.
<DDENTITY_COLUMN>-FIELDNAME_RAW = 1.
<DDENTITY_COLUMN>-POSITION = 1.
<DDENTITY_COLUMN>-KEYFLAG = 1.

ENDLOOP.

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

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_DDENTITY_COLUMN-DDLANGUAGE, sy-vline,
  WA_DDENTITY_COLUMN-ROLLNAME, sy-vline,
  WA_DDENTITY_COLUMN-DATATYPE, sy-vline,
  WA_DDENTITY_COLUMN-LENG, sy-vline,
  WA_DDENTITY_COLUMN-DECIMALS, sy-vline,
  WA_DDENTITY_COLUMN-DOMNAME, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_DDENTITY_COLUMN 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_DDENTITY_COLUMN 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_DDENTITY_COLUMN INTO WA_DDENTITY_COLUMN.


*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 ISOLA, internal->external for field DDLANGUAGE
CALL FUNCTION 'CONVERSION_EXIT_ISOLA_OUTPUT'
  EXPORTING
    input =                      WA_DDENTITY_COLUMN-DDLANGUAGE
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_DDENTITY_COLUMN-DDLANGUAGE.
WRITE:/ 'New Value:', ld_input.

*Conversion exit DTYPE, internal->external for field DATATYPE
CALL FUNCTION 'CONVERSION_EXIT_DTYPE_OUTPUT'
  EXPORTING
    input =                      WA_DDENTITY_COLUMN-DATATYPE
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_DDENTITY_COLUMN-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_DDENTITY_COLUMN_STR, 
ENTITYNAME TYPE STRING,
FIELDNAME TYPE STRING,
FIELDNAME_RAW TYPE STRING,
POSITION TYPE STRING,
KEYFLAG TYPE STRING,
DDLANGUAGE TYPE STRING,
ROLLNAME TYPE STRING,
DATATYPE TYPE STRING,
LENG TYPE STRING,
DECIMALS TYPE STRING,
DOMNAME TYPE STRING,
DEPTH TYPE STRING,
DESCRIPTION TYPE STRING,
IS_VIRTUAL TYPE STRING,
IS_CALCULATED TYPE STRING,
EXTENDNAME TYPE STRING,END OF T_EKKO_STR.
DATA: WA_DDENTITY_COLUMN_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_DDENTITY_COLUMN_STR-ENTITYNAME sy-vline 
WA_DDENTITY_COLUMN_STR-FIELDNAME sy-vline 
WA_DDENTITY_COLUMN_STR-FIELDNAME_RAW sy-vline 
WA_DDENTITY_COLUMN_STR-POSITION sy-vline 
WA_DDENTITY_COLUMN_STR-KEYFLAG sy-vline 
WA_DDENTITY_COLUMN_STR-DDLANGUAGE sy-vline 
WA_DDENTITY_COLUMN_STR-ROLLNAME sy-vline 
WA_DDENTITY_COLUMN_STR-DATATYPE sy-vline 
WA_DDENTITY_COLUMN_STR-LENG sy-vline 
WA_DDENTITY_COLUMN_STR-DECIMALS sy-vline 
WA_DDENTITY_COLUMN_STR-DOMNAME sy-vline 
WA_DDENTITY_COLUMN_STR-DEPTH sy-vline 
WA_DDENTITY_COLUMN_STR-DESCRIPTION sy-vline 
WA_DDENTITY_COLUMN_STR-IS_VIRTUAL sy-vline 
WA_DDENTITY_COLUMN_STR-IS_CALCULATED sy-vline 
WA_DDENTITY_COLUMN_STR-EXTENDNAME sy-vline      INTO ld_text SEPARATED BY SPACE.

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