ABAP Select data from SAP table TCNVF into internal table

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

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

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

*Select data and declare internal table using in-line method @DATA
*SELECT *
*  FROM TCNVF
*  INTO TABLE @DATA(IT_TCNVF2).
*--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_TCNVF INDEX 1 INTO DATA(WA_TCNVF2).


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

*To update a field value using a field symbol simply change the value via the field symbol pointer
<TCNVF>-MANDT = 1.
<TCNVF>-APPLIC = 1.
<TCNVF>-SUBAPP = 1.
<TCNVF>-LSTVAR = 1.
<TCNVF>-LINTYP = 1.

ENDLOOP.

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

*Write selected data to screen/report before conversion.
  WRITE:/ sy-vline,   WA_TCNVF-OBJECT, sy-vline,
  WA_TCNVF-LINE, sy-vline,
  WA_TCNVF-POSIT, sy-vline,
  WA_TCNVF-FIELD, sy-vline,
  WA_TCNVF-FDLEN, sy-vline,
  WA_TCNVF-FDTYPE, sy-vline.
ENDLOOP.
   
*Add any further fields from structure WA_TCNVF 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_TCNVF 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_TCNVF INTO WA_TCNVF.


*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_TCNVF_STR, 
MANDT TYPE STRING,
APPLIC TYPE STRING,
SUBAPP TYPE STRING,
LSTVAR TYPE STRING,
LINTYP TYPE STRING,
OBJECT TYPE STRING,
LINE TYPE STRING,
POSIT TYPE STRING,
FIELD TYPE STRING,
FDLEN TYPE STRING,
FDTYPE TYPE STRING,
ODECIMALS TYPE STRING,
EDITMASK TYPE STRING,
NOINIT TYPE STRING,
STDATR TYPE STRING,
COLOR TYPE STRING,
INTENS TYPE STRING,
INVERS TYPE STRING,
INPUT TYPE STRING,
HOTSPOT TYPE STRING,END OF T_EKKO_STR.
DATA: WA_TCNVF_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_TCNVF_STR-MANDT sy-vline 
WA_TCNVF_STR-APPLIC sy-vline 
WA_TCNVF_STR-SUBAPP sy-vline 
WA_TCNVF_STR-LSTVAR sy-vline 
WA_TCNVF_STR-LINTYP sy-vline 
WA_TCNVF_STR-OBJECT sy-vline 
WA_TCNVF_STR-LINE sy-vline 
WA_TCNVF_STR-POSIT sy-vline 
WA_TCNVF_STR-FIELD sy-vline 
WA_TCNVF_STR-FDLEN sy-vline 
WA_TCNVF_STR-FDTYPE sy-vline 
WA_TCNVF_STR-ODECIMALS sy-vline 
WA_TCNVF_STR-EDITMASK sy-vline 
WA_TCNVF_STR-NOINIT sy-vline 
WA_TCNVF_STR-STDATR sy-vline 
WA_TCNVF_STR-COLOR sy-vline 
WA_TCNVF_STR-INTENS sy-vline 
WA_TCNVF_STR-INVERS sy-vline 
WA_TCNVF_STR-INPUT sy-vline 
WA_TCNVF_STR-HOTSPOT sy-vline      INTO ld_text SEPARATED BY SPACE.

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