📘 Relational Database Design – Important PYQs

🔹 Unit 1: Basics of Relational Model

⭐ Very Repeated

1. Define Relation, Tuple, Attribute, Domain with example.

2. What is Relational Model? Explain its features.

3. Explain Keys in DBMS. Types of keys with examples.

4. Difference between:

   • Primary key vs Foreign key

   • Super key vs Candidate key

5. What is Integrity Constraint? Explain types.

🔹 Unit 2: Functional Dependency (FD)

⭐ Most Important (every year asked)

6. Define Functional Dependency with example.

7. Explain:

   • Trivial FD

   • Non-trivial FD

   • Fully functional dependency

8. Find closure of attribute set.

9. Find candidate keys using FD.

10. Explain Armstrong’s Axioms.

11. What is Minimal Cover / Canonical Cover? Find minimal cover of given FD set.

12. Check whether FD holds or not for a relation.

🔹 Unit 3: Normalization (🔥 Most asked topic)

⭐ Must Prepare 100%

13. What is Normalization? Why needed?

14. Explain:

• 1NF

• 2NF

• 3NF

• BCNF

15. Difference between 2NF, 3NF, BCNF.

16. Convert relation into 1NF/2NF/3NF.

17. Normalize given table up to BCNF.

18. What is Partial Dependency?

19. What is Transitive Dependency?

20. Decompose relation into 3NF.

21. Decompose relation into BCNF.

22. Explain Lossless Join Decomposition.

23. Explain Dependency Preservation.

24. Check whether decomposition is lossless or not.

🔹 Unit 4: Decomposition

25. What is Decomposition?

26. Types of decomposition.

27. Lossless vs Lossy decomposition.

28. Dependency preserving decomposition.

29. Algorithm for 3NF decomposition.

30. BCNF decomposition algorithm.

🔹 Unit 5: ER to Relational Mapping

31. Convert ER Diagram to Relational Schema.

32. Map:

• One-to-One relationship

• One-to-Many

• Many-to-Many

33. Weak entity mapping.

34. Multivalued attribute mapping.

35. Specialization & Generalization mapping.

📌 Long Answer Questions (5–10 marks)

These are commonly asked:

✔ Normalize given relation step by step
✔ Find candidate key and minimal cover
✔ Decompose into BCNF with proof
✔ Design database for:

• Library management system

• Student management system

• Banking system

• Hospital system

• Railway reservation system

📌 Short Notes (2–3 marks)

Prepare definitions:

• Super key

• Candidate key

• Composite key

• Surrogate key

• FD

• Normalization

• Anomaly (Insertion, Deletion, Update)

• Lossless join

• Dependency preservation