ABAP Select data from SAP table /MSG/4_PSREFMODFIELD into internal table

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Below is a number of ABAP code snippets to demonstrate how to select data from SAP /MSG/4_PSREFMODFIELD 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 /MSG/4_PSREFMODFIELD. 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 /MSG/4_PSREFMODFIELD 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_/MSG/4_PSREFMODFIELD TYPE STANDARD TABLE OF /MSG/4_PSREFMODFIELD,
      WA_/MSG/4_PSREFMODFIELD TYPE /MSG/4_PSREFMODFIELD,
      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: </MSG/4_PSREFMODFIELD> TYPE /MSG/4_PSREFMODFIELD.

*Process all fields in table header/work area as string values
  PERFORM process_as_string_field_values CHANGING wa_/MSG/4_PSREFMODFIELD.

SELECT *
*restrict ABAP select to first 10 rows
 UP TO 10 ROWS      
  FROM /MSG/4_PSREFMODFIELD
  INTO TABLE IT_/MSG/4_PSREFMODFIELD.

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM /MSG/4_PSREFMODFIELD
*  INTO TABLE @DATA(IT_/MSG/4_PSREFMODFIELD2).
*--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_/MSG/4_PSREFMODFIELD INDEX 1 INTO DATA(WA_/MSG/4_PSREFMODFIELD2).


*Demonstrate how to loop at an internal table and update values using a FIELD-SYMBOL
LOOP AT IT_/MSG/4_PSREFMODFIELD ASSIGNING </MSG/4_PSREFMODFIELD>.

*To update a field value using a field symbol simply change the value via the field symbol pointer
</MSG/4_PSREFMODFIELD>-TABNAME = 1.
</MSG/4_PSREFMODFIELD>-PM_CLASSNAME = 1.
</MSG/4_PSREFMODFIELD>-RM_CLASSNAME = 1.
</MSG/4_PSREFMODFIELD>-FIELDNAME = 1.
</MSG/4_PSREFMODFIELD>-PM_MARKNAME = 1.

ENDLOOP.

LOOP AT IT_/MSG/4_PSREFMODFIELD INTO WA_/MSG/4_PSREFMODFIELD.
*Write horizonal line to screen report.
  WRITE:/ sy-uline.

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_/MSG/4_PSREFMODFIELD-EXTFIELDNAME, sy-vline,
  WA_/MSG/4_PSREFMODFIELD-DATATYPE, sy-vline,
  WA_/MSG/4_PSREFMODFIELD-PM_DATATYPE, sy-vline,
  WA_/MSG/4_PSREFMODFIELD-APPLTYPE, sy-vline,
  WA_/MSG/4_PSREFMODFIELD-MULTIPLESET, sy-vline,
  WA_/MSG/4_PSREFMODFIELD-FIELD_CD, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_/MSG/4_PSREFMODFIELD 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_/MSG/4_PSREFMODFIELD 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_/MSG/4_PSREFMODFIELD INTO WA_/MSG/4_PSREFMODFIELD.


*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_/MSG/4_PSREFMODFIELD-DATATYPE
  IMPORTING
    output =                     ld_input.
WRITE:/ 'Org Value:', WA_/MSG/4_PSREFMODFIELD-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_/MSG/4_PSREFMODFIELD_STR, 
TABNAME TYPE STRING,
PM_CLASSNAME TYPE STRING,
RM_CLASSNAME TYPE STRING,
FIELDNAME TYPE STRING,
PM_MARKNAME TYPE STRING,
EXTFIELDNAME TYPE STRING,
DATATYPE TYPE STRING,
PM_DATATYPE TYPE STRING,
APPLTYPE TYPE STRING,
MULTIPLESET TYPE STRING,
FIELD_CD TYPE STRING,
PM_DATATYPECD TYPE STRING,
PROPERTY_CD TYPE STRING,
CLASS_ID TYPE STRING,
PM_DIMENSION TYPE STRING,
PM_UPC_MARKNAME TYPE STRING,
EXTTABNAME TYPE STRING,END OF T_EKKO_STR.
DATA: WA_/MSG/4_PSREFMODFIELD_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_/MSG/4_PSREFMODFIELD_STR-TABNAME sy-vline 
WA_/MSG/4_PSREFMODFIELD_STR-PM_CLASSNAME sy-vline 
WA_/MSG/4_PSREFMODFIELD_STR-RM_CLASSNAME sy-vline 
WA_/MSG/4_PSREFMODFIELD_STR-FIELDNAME sy-vline 
WA_/MSG/4_PSREFMODFIELD_STR-PM_MARKNAME sy-vline 
WA_/MSG/4_PSREFMODFIELD_STR-EXTFIELDNAME sy-vline 
WA_/MSG/4_PSREFMODFIELD_STR-DATATYPE sy-vline 
WA_/MSG/4_PSREFMODFIELD_STR-PM_DATATYPE sy-vline 
WA_/MSG/4_PSREFMODFIELD_STR-APPLTYPE sy-vline 
WA_/MSG/4_PSREFMODFIELD_STR-MULTIPLESET sy-vline 
WA_/MSG/4_PSREFMODFIELD_STR-FIELD_CD sy-vline 
WA_/MSG/4_PSREFMODFIELD_STR-PM_DATATYPECD sy-vline 
WA_/MSG/4_PSREFMODFIELD_STR-PROPERTY_CD sy-vline 
WA_/MSG/4_PSREFMODFIELD_STR-CLASS_ID sy-vline 
WA_/MSG/4_PSREFMODFIELD_STR-PM_DIMENSION sy-vline 
WA_/MSG/4_PSREFMODFIELD_STR-PM_UPC_MARKNAME sy-vline 
WA_/MSG/4_PSREFMODFIELD_STR-EXTTABNAME sy-vline      INTO ld_text SEPARATED BY SPACE.

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