SAP ABAP INTERVIEW QUESTIONS ANSWERS MADE EASY

1. Pass by Reference in ABAP: In ABAP, parameters can be passed by reference using pointers (reference to tables, objects, or data structures). When you use a pointer, any changes made to the parameter within the function module are reflected in the calling program because both are referencing the same memory location.

2. RFC Function Module: An RFC (Remote Function Call) function module allows a program running in one ABAP system to call functions in another ABAP system. The parameters can be passed by value or by reference, depending on the data type and requirements.

3. Function Module in SAP: A function module is a unit of program code that encapsulates specific functionality. It is used for modularization, reusability, and encapsulation of functions to improve maintainability and enhance performance in SAP.

4. Extra Steps for RFC Function Modules: When creating an RFC function module, you need to ensure that the ABAP dictionary types are correctly defined and that the function module is activated for remote enable. You also need to consider the data type conversion between the source system and the target system when dealing with different ABAP versions or platforms.

5. Update Function Module: An update function module (FUND = 'U' in SE37) allows updating data in the database. It is triggered when a record in an internal table is modified before the table is written back to the database.

6. Types of Function Modules: There are several types of function modules, including standard, collective, update, and subroutine (or include) function modules. Each type serves a different purpose.

7. When Update FM Gets Triggered: An update function module is triggered before an internal table is written to the database (POST PROCESSING OUTPUT), after it has been read from the database (POST PROCESSING INPUT), or manually when you explicitly call it using the UPDATE KEY command.

8. Syntax for Update Function Module: The syntax for defining an update function module starts with FUNCTION update_fm and includes an importing parameter for each field that can be changed.

9. Multiple Update FMs: When there are multiple update function modules, they are stored in the ABAP dictionary, and the sequence in which they are triggered is determined by the table type's settings. The system checks for updates from top to bottom in the list of registered update functions.

10. Types of Update Function Modules: There are two main types: type 'A' (standard) and type 'B' (collected). Type 'A' is triggered individually for each record, while type 'B' is triggered once after all records have been processed.

11. Collective Run Update Function Module: A collective run update function module is used to perform updates on multiple records at once. It is useful when the update logic does not depend on the individual data records.

12. Practical Example for Update Function Module: Consider an internal table containing customer data that needs to be updated. You would define an update function module that processes these changes and commits them to the database.

Regarding your other questions:

• Mandatory Check for ALL Entries: Before using FOR ALL ENTRIES, ensure that all necessary fields are set for each entry to avoid runtime errors.

• Different Types of Internal Tables: Standard tables are the basic form, sorted tables have a sort key, and hashed tables are optimized for fast access by a specific key.

• Primary and Secondary Keys: The primary key uniquely identifies each record in a table, while the secondary key is an additional field used to distinguish between different records with the same primary key.

• Modularization Techniques: Modularization helps organize code, simplify maintenance, and optimize performance by breaking down complex programs into smaller, manageable units.

• Field Symbols: ABAP supports four types of field symbols: simple, composite, table, and variant.

• Data References: Data references are pointers to data objects in memory, allowing for direct access and manipulation of the referenced data.

• Different System Variables in ABAP: Variables like SY-SUBRC, SY-INDEX, SY-TABIX, SY-DBCODE, etc., hold system-related information that can be used within programs.

• SQL Types: There are two main types of SQL: DML (Data Manipulation Language) and DQL (Data Query Language).

• Open SQL and Native SQL: Open SQL is a platform-independent SQL statement, while Native SQL is the specific SQL dialect understood by the underlying database system.

• RFC Function Module Parameters: Parameters can be passed by value or by reference. For value passing, the actual data is copied; for reference passing, a pointer to the data is used (typically for tables and structures).

Remember that some of these concepts may have evolved with newer versions of SAP, so always refer to the latest SAP documentation or best practices when implementing these features.