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Module 34: ABAP Interview Preparation

This module prepares you for real-world ABAP interviews, covering:

  • Classic ABAP fundamentals
  • OOP concepts
  • HANA & CDS thinking
  • AMDP & performance scenarios
  • RAP & OData (modern ABAP)

Each section includes typical questions + interview-ready answers.

1. Classic ABAP Questions​

Q1. Difference between SELECT SINGLE and SELECT UP TO 1 ROWS?​

Answer:

  • SELECT SINGLE does not guarantee order
  • SELECT UP TO 1 ROWS must be used with ORDER BY
SELECT * FROM ztable
  ORDER BY created_on DESC
  UP TO 1 ROWS
  INTO @DATA(ls_data).
ENDSELECT.
Interview Tip

Say: “SELECT UP TO 1 ROWS with ORDER BY is deterministic.”

Q2. Types of Internal Tables and When to Use Them?​

Answer:

  • STANDARD → Sequential access
  • SORTED → Range & key access
  • HASHED → Fast key access
Golden Rule

If you use READ TABLE ... WITH KEY, prefer HASHED or SORTED.

2. OOP (ABAP Objects) Questions​

Q3. Difference between Abstract Class and Interface?​

AspectAbstract ClassInterface
ImplementationPartialNone
Multiple Inheritance❌✅
ConstructorsYesNo
Interview Line

"Use interfaces for behavior contracts, abstract classes for shared logic."

Q4. What is Polymorphism in ABAP?​

Answer:

Ability to treat different implementations uniformly via interfaces or superclass references.

DATA lo_calc TYPE REF TO zif_tax_calc.
lo_calc = zcl_tax_factory=>get_calculator( iv_country ).

3. HANA & CDS Questions​

Q5. Why CDS Instead of Open SQL?​

Answer:

  • Semantic layer
  • Reusable
  • Authorization-aware
  • Optimized pushdown
Strong Answer

"CDS is not just SQL—it's a semantic data model."

Q6. Association vs Join in CDS?​

Answer:

  • Joins → Eager loading
  • Associations → Lazy, reusable, semantic
SAP Recommendation

Prefer associations unless eager data is required.

4. AMDP & Performance Scenarios​

Q7. When Do You Use AMDP?​

Answer:

  • Very large datasets
  • Procedural DB logic
  • CDS insufficient
Interview Trap

Never say "AMDP for performance always" ❌

Q8. How Do You Avoid Nested SELECTs?​

Answer:

  • Use JOINs
  • Use CDS
  • Push logic to DB
SELECT a~id, b~text
  FROM ztab1 AS a
  INNER JOIN ztab2 AS b
    ON a~id = b~id
  INTO TABLE @DATA(lt_data).

5. RAP & OData Questions (Very Important)​

Q9. Managed vs Unmanaged RAP?​

Answer:

  • Managed → Framework handles CRUD, lock, commit
  • Unmanaged → Developer handles everything
Interview Gold

"Managed RAP is the default choice for new developments."

Q10. RAP vs SEGW?​

Answer:

  • SEGW → Code-heavy, OData V2
  • RAP → CDS-based, OData V4, future-proof

Q11. What is Draft Handling in RAP?​

Answer:

Allows saving incomplete data, resuming later, and ensures safe multi-user editing.

RAP Advantage

Draft is built-in, not custom.

6. Scenario-Based Questions​

Scenario 1: Performance Issue in Production​

Expected Answer:

  • Analyze ST05 / SAT
  • Reduce data volume
  • Push logic to DB
  • Use CDS / Open SQL
  • Validate with ATC

Scenario 2: Authorization Issue in Fiori App​

Expected Answer:

  • Check CDS authorization
  • Verify DCL
  • Validate PFCG role
  • Avoid UI-only checks

7. Rapid-Fire Questions (Quick Round)​

Practice These
  • Difference between COMMIT WORK and BAPI commit?
  • What is SAP LUW?
  • How does RAP handle transactions?
  • Why ATC is mandatory in S/4?
  • Why SELECT * is discouraged?

8. Final Interview Tips​

Must-Do
  • Always think Clean ABAP
  • Prefer CDS over Open SQL
  • Avoid legacy syntax
  • Mention ATC & testing
  • Speak in design decisions, not syntax

9. One-Line Power Answers​

  • "RAP is SAP's strategic backend model."
  • "CDS is the semantic layer in S/4HANA."
  • "Performance is about data volume, not loops."
  • "ATC enforces quality, not style."

10. Summary​

  • Interviews test thinking, not memorization
  • Modern ABAP = CDS + RAP + Clean Code
  • Performance & security are mandatory topics
  • Design decisions matter more than syntax

11. What's Next?​

➡️ Module 35: Capstone Projects

Learning Tip

If you can explain why you chose a solution, you've already cleared the interview.