ABAP Select data from SAP table DMECD_TREE_LEVEL into internal table

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

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

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

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM DMECD_TREE_LEVEL
*  INTO TABLE @DATA(IT_DMECD_TREE_LEVEL2).
*--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_DMECD_TREE_LEVEL INDEX 1 INTO DATA(WA_DMECD_TREE_LEVEL2).


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

*To update a field value using a field symbol simply change the value via the field symbol pointer
<DMECD_TREE_LEVEL>-MANDT = 1.
<DMECD_TREE_LEVEL>-DRAFTUUID = 1.
<DMECD_TREE_LEVEL>-PARENTDRAFTUUID = 1.
<DMECD_TREE_LEVEL>-HIERARCHYTREETYPE = 1.
<DMECD_TREE_LEVEL>-HIERARCHYTREE = 1.

ENDLOOP.

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

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_DMECD_TREE_LEVEL-HIERARCHYTREEVERSION, sy-vline,
  WA_DMECD_TREE_LEVEL-HIERARCHYNODELEVEL, sy-vline,
  WA_DMECD_TREE_LEVEL-LEVELREPETITIONLIMITVALUE, sy-vline,
  WA_DMECD_TREE_LEVEL-HASACTIVEENTITY, sy-vline,
  WA_DMECD_TREE_LEVEL-DRAFTENTITYCREATIONDATETIME, sy-vline,
  WA_DMECD_TREE_LEVEL-DRAFTENTITYLASTCHANGEDATETIME, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_DMECD_TREE_LEVEL 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_DMECD_TREE_LEVEL 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_DMECD_TREE_LEVEL INTO WA_DMECD_TREE_LEVEL.


*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_DMECD_TREE_LEVEL_STR, 
MANDT TYPE STRING,
DRAFTUUID TYPE STRING,
PARENTDRAFTUUID TYPE STRING,
HIERARCHYTREETYPE TYPE STRING,
HIERARCHYTREE TYPE STRING,
HIERARCHYTREEVERSION TYPE STRING,
HIERARCHYNODELEVEL TYPE STRING,
LEVELREPETITIONLIMITVALUE TYPE STRING,
HASACTIVEENTITY TYPE STRING,
DRAFTENTITYCREATIONDATETIME TYPE STRING,
DRAFTENTITYLASTCHANGEDATETIME TYPE STRING,
DRAFTADMINISTRATIVEDATAUUID TYPE STRING,
DRAFTENTITYCONSISTENCYSTATUS TYPE STRING,
DRAFTENTITYOPERATIONCODE TYPE STRING,END OF T_EKKO_STR.
DATA: WA_DMECD_TREE_LEVEL_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_DMECD_TREE_LEVEL_STR-MANDT sy-vline 
WA_DMECD_TREE_LEVEL_STR-DRAFTUUID sy-vline 
WA_DMECD_TREE_LEVEL_STR-PARENTDRAFTUUID sy-vline 
WA_DMECD_TREE_LEVEL_STR-HIERARCHYTREETYPE sy-vline 
WA_DMECD_TREE_LEVEL_STR-HIERARCHYTREE sy-vline 
WA_DMECD_TREE_LEVEL_STR-HIERARCHYTREEVERSION sy-vline 
WA_DMECD_TREE_LEVEL_STR-HIERARCHYNODELEVEL sy-vline 
WA_DMECD_TREE_LEVEL_STR-LEVELREPETITIONLIMITVALUE sy-vline 
WA_DMECD_TREE_LEVEL_STR-HASACTIVEENTITY sy-vline 
WA_DMECD_TREE_LEVEL_STR-DRAFTENTITYCREATIONDATETIME sy-vline 
WA_DMECD_TREE_LEVEL_STR-DRAFTENTITYLASTCHANGEDATETIME sy-vline 
WA_DMECD_TREE_LEVEL_STR-DRAFTADMINISTRATIVEDATAUUID sy-vline 
WA_DMECD_TREE_LEVEL_STR-DRAFTENTITYCONSISTENCYSTATUS sy-vline 
WA_DMECD_TREE_LEVEL_STR-DRAFTENTITYOPERATIONCODE sy-vline      INTO ld_text SEPARATED BY SPACE.

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