15 ABAP Interview Questions and Answers

ABAP (Advanced Business Application Programming) is a high-level programming language created by SAP for developing applications on the SAP platform. It is integral to the customization and enhancement of SAP software, making it a critical skill for professionals working with SAP systems. ABAP’s robust capabilities allow for the development of complex business processes and data management tasks, making it indispensable in enterprise environments.

This article offers a curated selection of ABAP interview questions designed to help you demonstrate your proficiency and understanding of the language. By reviewing these questions and their answers, you will be better prepared to showcase your technical expertise and problem-solving abilities in an interview setting.

ABAP Interview Questions and Answers

1. What is the purpose of a Data Dictionary?

The Data Dictionary in ABAP acts as a centralized repository for metadata, including definitions of data types, structures, tables, views, and indexes. It ensures data consistency and integrity across the SAP system by allowing developers to reuse data definitions, reducing redundancy and potential errors. The Data Dictionary enforces data types and constraints, such as primary keys and foreign keys, to maintain data quality. It also provides tools for managing metadata and generating database objects to align the physical database structure with the logical data model.

2. What are the different types of views in Data Dictionary?

In the ABAP Data Dictionary, there are four main types of views:

• Database View: Combines data from multiple tables using an inner join and can be accessed like a regular table.
• Projection View: Hides certain fields of a table, providing a subset of fields to simplify data access.
• Help View: Provides data for search helps, combining data from multiple tables using an outer join to enhance user experience.
• Maintenance View: Allows for consistent data maintenance across related tables, enabling creation, modification, and deletion of data.

3. What is an ALV report and how do you create one?

An ALV (ABAP List Viewer) report is a tool in SAP for flexible and interactive data display, offering functionalities like sorting and filtering. To create an ALV report, follow these steps:

• Define and populate the internal table with data.
• Define the field catalog, describing the structure and properties of the ALV grid columns.
• Use the function module REUSE_ALV_GRID_DISPLAY to display the data in ALV format.

Here is a high-level overview of the key components involved in creating an ALV report:

DATA: lt_data TYPE TABLE OF <data_structure>,
      lt_fieldcat TYPE lvc_t_fcat.

* Populate the internal table lt_data with data

* Define the field catalog
CALL FUNCTION 'LVC_FIELDCATALOG_MERGE'
  EXPORTING
    i_structure_name = '<data_structure>'
  CHANGING
    ct_fieldcat      = lt_fieldcat.

* Display the ALV report
CALL FUNCTION 'REUSE_ALV_GRID_DISPLAY'
  EXPORTING
    it_fieldcat = lt_fieldcat
  TABLES
    t_outtab    = lt_data.

4. Explain the difference between a BAPI and a BADI.

BAPI (Business Application Programming Interface) and BADI (Business Add-In) are both integral parts of SAP’s ABAP programming environment, serving different purposes.

BAPI:

• Standardized interfaces for external applications to interact with SAP systems, used for data exchange.
• Defined in the Business Object Repository (BOR) and implemented as methods of SAP business objects.
• Used for creating, updating, or retrieving data in SAP.

BADI:

• Enhancements allowing custom code in SAP applications without modifying the original code.
• Part of the SAP enhancement framework, defined as enhancement points in standard SAP code.
• Used to extend SAP applications’ functionality in a controlled manner.

5. How do you implement a BADI?

To implement a BADI in ABAP, follow these steps:

• Create a BADI definition using transaction SE18.
• Implement the BADI using transaction SE19.
• Use the BADI in your ABAP code.

Example:

" Step 1: Create a BADI definition
" Go to transaction SE18 and create a new BADI definition

" Step 2: Implement the BADI
" Go to transaction SE19 and create a new BADI implementation for the definition created in step 1

METHOD if_badi_interface~method_name.
  " Your custom code here
ENDMETHOD.

" Step 3: Use the BADI in your ABAP code
DATA: badi_instance TYPE REF TO if_badi_interface.
GET BADI badi_instance.
CALL BADI badi_instance->method_name.

6. What is the purpose of a lock object?

Lock objects in ABAP manage concurrent access to data in a database, ensuring data consistency when multiple users or processes access the same data. Defined in the ABAP Dictionary, they work with enqueue and dequeue function modules to lock and unlock data records. Lock objects generate function modules for setting and releasing locks, controlling data access. Different types of locks, such as shared and exclusive locks, serve various access control needs.

7. Describe the process of creating a module pool program.

Creating a module pool program in ABAP involves several steps:

• Define the Program and Screens: Create a new module pool program using transaction SE80, defining the program name and initial screen.
• Design the Screen Layout: Use the Screen Painter tool to design each screen’s layout, placing UI elements like input fields and buttons.
• Write Flow Logic: Each screen has its own flow logic, written in the screen’s PBO (Process Before Output) and PAI (Process After Input) modules.
• Create Dialog Modules: Define dialog modules in the main program to handle specific tasks, called from the screen’s flow logic.
• Implement Event Handling: Handle user actions like button clicks and field validations in the PAI module.
• Test and Debug: Thoroughly test the module pool program and use the SAP debugger to troubleshoot issues.

8. What are the different types of RFCs?

In ABAP, Remote Function Calls (RFCs) enable communication between SAP systems or with external systems. Types of RFCs include:

• Synchronous RFC (sRFC): The calling program waits for the called function module to complete and return the result.
• Asynchronous RFC (aRFC): The calling program continues processing without waiting for the result, useful for parallel processing.
• Transactional RFC (tRFC): Ensures the called function module executes exactly once, even if the system fails during the call.
• Queued RFC (qRFC): An extension of tRFC that processes function calls in a specific sequence, important for dependent transactions.

9. What is the significance of the SY-SUBRC variable?

The SY-SUBRC variable in ABAP stores the return code of the last executed statement, used for error handling and controlling program flow. For example, when using the SELECT statement to fetch data, SY-SUBRC indicates if the operation was successful:

SELECT SINGLE * FROM mara INTO @DATA(ls_mara) WHERE matnr = @lv_matnr.
IF sy-subrc = 0.
    WRITE: / 'Material found:', ls_mara-matnr.
ELSE.
    WRITE: / 'Material not found'.
ENDIF.

In this example, if the material number is found, SY-SUBRC is set to 0, and the program writes “Material found” with the material number. If not found, SY-SUBRC is non-zero, and the program writes “Material not found.”

10. How do you implement parallel processing?

Parallel processing in ABAP can be achieved using methods like background jobs, asynchronous RFC, and parallel cursor. These methods distribute the workload across multiple processes to improve performance. Asynchronous RFCs allow multiple function modules to run in parallel, useful for tasks that can be divided into independent units.

Example:

DATA: lt_dest TYPE TABLE OF rfcdest,
      lt_result TYPE TABLE OF result.

" Define destinations for parallel processing
lt_dest = VALUE #( ( 'DEST1' ) ( 'DEST2' ) ( 'DEST3' ) ).

" Call function module in parallel
CALL FUNCTION 'Z_MY_FUNCTION'
  STARTING NEW TASK lt_dest
  DESTINATION IN GROUP 'PARALLEL_GROUP'
  PERFORMING callback ON END OF TASK
  EXPORTING
    it_data = lt_data.

" Callback to handle results
FORM callback USING taskname.
  RECEIVE RESULTS FROM FUNCTION 'Z_MY_FUNCTION'
    IMPORTING
      et_result = lt_result.
ENDFORM.

11. Explain the different data types and structures in ABAP.

ABAP supports various data types and structures to handle different kinds of data efficiently.

Elementary Data Types:

• Numeric Types: Include Integer (I), Packed Decimal (P), and Floating Point (F).
• Character Types: Include Character (C), String (STRING), and Numeric Text (N).
• Date/Time Types: Include Date (D) and Time (T).

Complex Data Types:

• Structures: Group different data types together, containing multiple fields of different types.
• Internal Tables: Store multiple records of the same type, similar to arrays but more flexible.

Reference Types:

• Data References: Pointers to data objects.
• Object References: Pointers to instances of classes.

12. What is the SAP Enhancement Framework and how is it used?

The SAP Enhancement Framework allows developers to add custom functionality to standard SAP applications without altering the original codebase. This ensures custom enhancements do not interfere with standard SAP updates, maintaining system stability.

The framework includes:

• Enhancement Points: Predefined spots in the standard SAP code for custom code insertion.
• Enhancement Sections: Allow replacing standard code with custom code.
• BAdIs (Business Add-Ins): Object-oriented enhancements providing predefined interfaces for custom implementations.
• Explicit Enhancements: Custom enhancements explicitly defined by the developer.
• Implicit Enhancements: Enhancements implicitly available at certain code points, like the start and end of methods.

To use the framework, a developer identifies the appropriate enhancement point or section in the standard SAP code and creates an enhancement implementation containing the custom code.

13. How do you implement authorization objects in ABAP?

Authorization objects in ABAP control access to data and transactions within the SAP system. They consist of fields specifying conditions for access, assigned to roles, which are then assigned to users.

To implement authorization objects in ABAP:

• Create an authorization object in the SAP system.
• Define fields and permissible values for the object.
• Assign the object to a role and the role to a user.
• Check for authorization within the ABAP code using the AUTHORITY-CHECK statement.

Example:

AUTHORITY-CHECK OBJECT 'Z_MY_AUTH_OBJ'
  ID 'ACTVT' FIELD '03'
  ID 'ZFIELD' FIELD 'VALUE'.

IF sy-subrc <> 0.
  MESSAGE 'You do not have authorization' TYPE 'E'.
ENDIF.

14. What is Batch Data Communication (BDC) and how is it used?

Batch Data Communication (BDC) in SAP ABAP transfers data from external systems into the SAP system, used for data migration and batch processing. BDC simulates user input for transactions, automating data entry tasks. There are two main methods: the classical method (using transaction codes) and the call transaction method.

Example of the call transaction method:

DATA: lt_bdcdata TYPE TABLE OF bdcdata,
      ls_bdcdata TYPE bdcdata,
      lv_msg     TYPE string.

ls_bdcdata-program  = 'SAPMF02D'.
ls_bdcdata-dynpro   = '0100'.
ls_bdcdata-dynbegin = 'X'.
APPEND ls_bdcdata TO lt_bdcdata.

ls_bdcdata-fnam = 'BDC_OKCODE'.
ls_bdcdata-fval = '/00'.
APPEND ls_bdcdata TO lt_bdcdata.

CALL TRANSACTION 'FB01' USING lt_bdcdata
                   MODE 'A'
                   UPDATE 'S'
                   MESSAGES INTO lv_msg.

15. Explain the principles of Object-Oriented Programming (OOP).

Object-Oriented Programming (OOP) in ABAP is based on four principles: encapsulation, inheritance, polymorphism, and abstraction.

• Encapsulation: Bundles data and methods into a class, protecting data from unauthorized access.
• Inheritance: Allows a subclass to inherit properties and methods of a superclass, promoting code reusability.
• Polymorphism: Enables objects to be treated as instances of their parent class, allowing method interchangeability.
• Abstraction: Hides complex implementation details, showing only essential features to simplify interaction.

In ABAP, these principles are implemented using classes and interfaces. Classes are defined using the CLASS keyword, and methods are defined within the class. Inheritance is achieved using the INHERITING FROM keyword, and polymorphism is supported through method overriding and interfaces.