Dynamic Data visualization with dynamic column by using the ALV report

[AmveshKumar]

Implementation and Use Cases 

In the world of SAP ABAP, ALV (ABAP List Viewer) reports are one of the most widely used tools for presenting structured data. Often, the structure of the data is known beforehand, and columns are fixed during development. However, in some scenarios, the columns must be dynamically generated based on user input, runtime data, or specific business logic. 

This blog will guide you through the implementation of dynamic column generation in ALV and discuss use cases where this approach proves invaluable. 

What is Dynamic ALV Column Generation? 

Dynamic ALV column generation allows the developer to define and display columns at runtime rather than at design time. This is especially useful when: 

- The data structure is not static. 

- Columns depend on user input or database content. 

- Reports need to be adaptable for different business contexts or requirements. 

Implementation Steps 

Declarations  

declaring all the  tables, field symbols at the top which is required and others can be done through inline declarations. 

DATA: lt_fieldcat  TYPE lvc_t_fcat, 
      lt_data      TYPE REF TO data, 
      lt_table     TYPE REF TO data, 
      wa_table     TYPE REF TO data, 
      lo_alv_grid  TYPE REF TO cl_gui_alv_grid, 
      lt_layout    TYPE lvc_s_layo, 
      lo_container TYPE REF TO cl_gui_custom_container, 
      ok_code      TYPE sy-ucomm. 
FIELD-SYMBOLS: <lt_table> TYPE STANDARD TABLE. <ol><li><span>Create a Field Catalog Dynamically<span> <p><span>The field catalog determines the structure and properties of the ALV columns. For dynamic generation, you populate the field catalog at runtime based on your requirements.<span> <li-code lang="abap">" Define field catalog dynamically 
lt_fieldcat =  VALUE #( ( fieldname = 'MATNR' seltext   = 'Material'        col_pos   = 1 ) 
                        ( fieldname = 'MTART' seltext   = 'Material Type'   col_pos   = 2 ) 
                        ( fieldname = 'MBRSH' seltext   = 'Industry Sector' col_pos   = 3 ) )  . <ol><li><span>Define the Internal Table Structure Dynamically<span> <p><span>To handle dynamic data, use RTTS (Run-Time Type Services) to define the internal table and its fields at runtime.<span> <li-code lang="abap">CALL METHOD cl_alv_table_create=>create_dynamic_table 
  EXPORTING 
    it_fieldcatalog = lt_fieldcat 
  IMPORTING 
    ep_table        = lt_data. <ol><li><span>Populate the Dynamic Internal Table<span> <p><span>Populate the dynamically created internal table with data as per your requirement.<span> <li-code lang="abap">" Assign the created table to a field symbol 
ASSIGN lt_data->* TO <lt_table>. 
 
" Create work area dynamically 
CREATE DATA wa_table LIKE LINE OF <lt_table>. 
ASSIGN wa_table->* TO FIELD-SYMBOL(<wa_row>). 
 
SELECT matnr, 
       mtart, 
       mbrsh FROM mara 
  UP TO 10 ROWS INTO TABLE (lt_mara). 
 
LOOP AT lt_mara INTO DATA(ls_mara). 
 
  " Assign MATNR field dynamically 
  ASSIGN COMPONENT 'MATNR' OF STRUCTURE <wa_row> TO FIELD-SYMBOL(<fs_field>). 
  IF sy-subrc = 0. 
    <fs_field> = ls_mara-matnr. 
  ENDIF. 
 
  " Assign MTART field dynamically 
  ASSIGN COMPONENT 'MTART' OF STRUCTURE <wa_row> TO <fs_field>. 
  IF sy-subrc = 0. 
    <fs_field> = ls_mara-mtart. 
  ENDIF. 
 
  " Assign MBRSH field dynamically 
  ASSIGN COMPONENT 'MBRSH' OF STRUCTURE <wa_row> TO <fs_field>. 
  IF sy-subrc = 0. 
    <fs_field> = ls_mara-mbrsh. 
  ENDIF. 
 
  APPEND <wa_row> TO <lt_table>. 
ENDLOOP. <ol><li><span>Call the ALV Grid Display<span> <p><span>Pass the field catalog and internal table to the ALV function module or class.<span> <li-code lang="abap">" Create container for ALV display 
CREATE OBJECT lo_container 
  EXPORTING 
    container_name = 'ALV_CONTAINER'. 
 
" Create ALV Grid Object 
CREATE OBJECT lo_alv_grid 
  EXPORTING 
    i_parent = lo_container 
  EXCEPTIONS 
    OTHERS   = 1. 
 
" Set ALV layout 
lt_layout-grid_title = 'Dynamic ALV'. 
 
START-OF-SELECTION. 
 
  " Display ALV 
  CALL METHOD lo_alv_grid->set_table_for_first_display 
    EXPORTING 
      is_layout       = lt_layout 
    CHANGING 
      it_fieldcatalog = lt_fieldcat 
      it_outtab       = <lt_table>. 

Use declare a screen and make a container there and set the pf status. 

CALL SCREEN 2000. 
MODULE user_command_2000 INPUT. 
  ok_code = sy-ucomm. 
  CASE  ok_code. 
    WHEN 'BACK'. 
      LEAVE TO SCREEN 0 . 
    WHEN 'CANCEL'. 
      LEAVE SCREEN. 
    WHEN OTHERS. 
  ENDCASE. 
ENDMODULE. 
 
 
MODULE status_2000 OUTPUT. 
  SET PF-STATUS 'SCREEN'. 
* SET TITLEBAR 'xxx'. 
ENDMODULE. 

Use Cases 

1. User-Defined Reports 

   In scenarios where users need to select fields to display (e.g., selecting columns for a sales report), dynamic column generation enables customization without modifying the code. 

   1. Data-Driven Reports 

      When the structure of data depends on the content (e.g., different regions showing different key performance indicators), dynamic ALV ensures flexibility in column definitions. 

      1. Ad Hoc Queries 

      For scenarios requiring on-the-fly queries (e.g., dynamic filtering in a business intelligence tool), dynamically generating columns provides the necessary agility. 

      Advantages of Dynamic Column Generation 

      Flexibility:  Allows reports to adapt to varying requirements without code changes. 

      Reusability:  Reduces the need for creating multiple fixed-structure reports. 

      Improved User Experience:  Provides end-users with the ability to define their output structure. 

       Challenges and Troubleshooting  

      1.Performance Issues 

      Dynamic column generation might impact performance if not handled properly, especially with large datasets. Use appropriate indexing and minimize data reads. 

      2. Error Handling 

      Ensure robust error handling when working with RTTS to avoid runtime issues. 

      3.Debugging Complexity 

      Debugging dynamic structures can be challenging. Use `DESCRIBE` statements and test thoroughly. 

      Conclusion 

      Dynamic ALV column generation is a powerful feature that adds flexibility and scalability to your reports. By following the steps outlined above, you can implement this functionality effectively and address various business requirements. Embrace this technique to build more user-centric and adaptable SAP reports.