ABAP Select data from SAP table DMC_IFREG into internal table

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

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

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

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM DMC_IFREG
*  INTO TABLE @DATA(IT_DMC_IFREG2).
*--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_DMC_IFREG INDEX 1 INTO DATA(WA_DMC_IFREG2).


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

*To update a field value using a field symbol simply change the value via the field symbol pointer
<DMC_IFREG>-IFNM = 1.
<DMC_IFREG>-ATTRNM = 1.
<DMC_IFREG>-GUID = 1.
<DMC_IFREG>-ATTRIFNM = 1.
<DMC_IFREG>-ACTIVE = 1.

ENDLOOP.

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

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_DMC_IFREG-CRTMTHD, sy-vline,
  WA_DMC_IFREG-LOADMTHD, sy-vline,
  WA_DMC_IFREG-SKEY, sy-vline,
  WA_DMC_IFREG-CLASSNM, sy-vline,
  WA_DMC_IFREG-IDENT, sy-vline,
  WA_DMC_IFREG-DESCR, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_DMC_IFREG 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_DMC_IFREG 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_DMC_IFREG INTO WA_DMC_IFREG.


*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.
ENDFORM. 

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

TYPES: BEGIN OF T_DMC_IFREG_STR, 
IFNM TYPE STRING,
ATTRNM TYPE STRING,
GUID TYPE STRING,
ATTRIFNM TYPE STRING,
ACTIVE TYPE STRING,
CRTMTHD TYPE STRING,
LOADMTHD TYPE STRING,
SKEY TYPE STRING,
CLASSNM TYPE STRING,
IDENT TYPE STRING,
DESCR TYPE STRING,
AUTHOR TYPE STRING,
CHNAM TYPE STRING,
CREATEDATE TYPE STRING,
CHANGEDATE TYPE STRING,END OF T_EKKO_STR.
DATA: WA_DMC_IFREG_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_DMC_IFREG_STR-IFNM sy-vline 
WA_DMC_IFREG_STR-ATTRNM sy-vline 
WA_DMC_IFREG_STR-GUID sy-vline 
WA_DMC_IFREG_STR-ATTRIFNM sy-vline 
WA_DMC_IFREG_STR-ACTIVE sy-vline 
WA_DMC_IFREG_STR-CRTMTHD sy-vline 
WA_DMC_IFREG_STR-LOADMTHD sy-vline 
WA_DMC_IFREG_STR-SKEY sy-vline 
WA_DMC_IFREG_STR-CLASSNM sy-vline 
WA_DMC_IFREG_STR-IDENT sy-vline 
WA_DMC_IFREG_STR-DESCR sy-vline 
WA_DMC_IFREG_STR-AUTHOR sy-vline 
WA_DMC_IFREG_STR-CHNAM sy-vline 
WA_DMC_IFREG_STR-CREATEDATE sy-vline 
WA_DMC_IFREG_STR-CHANGEDATE sy-vline      INTO ld_text SEPARATED BY SPACE.

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