📊 Database Management Systems

MAKAUT B.Tech (Sem-6, 2022–23) – Detailed Solutions

✅ Group-A (1 Mark) | Group-B (5 Marks) | Group-C (15 Marks) | Exam-ready
📌 Group-A (Very Short Answer – 1 Mark Each)
(i) The information about data in a database is called

Answer: Metadata

(ii) Command used to modify a column inside a table

Answer: ALTER TABLE

(iii) Full form of NTFS

Answer: New Technology File System

(iv) Full form of TCL

Answer: Transaction Control Language

(v) _____ ACID property states that only valid data will be written

Answer: Consistency

(vi) Data stored in DBMS is in:

Answer: Files / Tables (organized database files)

(vii) Property ensuring transactions execute properly without interference

Answer: Isolation

(viii) Database design prevents anomaly due to

Answer: Normalization

(ix) Rules used to find logically implied functional dependencies are called

Answer: Armstrong’s Axioms

(x) Character function to return a specified portion of string in SQL

Answer: SUBSTRING() / SUBSTR()

(xi) Normal form satisfying multivalued dependency and BCNF

Answer: 4NF (Fourth Normal Form)

(xii) DBMS periodically suspends processing and synchronizes files using

Answer: Checkpoint

✍️ Group-B (Short Answer – 5 Marks)
2. Armstrong’s Three Axioms

Reflexivity: If Y ⊆ X, then X → Y (e.g., (A,B) → A). Augmentation: If X→Y, then XZ→YZ (e.g., A→B ⇒ AC→BC). Transitivity: If X→Y and Y→Z, then X→Z (e.g., A→B, B→C ⇒ A→C).

3. Functional Dependency

Definition: X → Y means Y is functionally dependent on X; if two tuples have same X value, they must have same Y. Example: Student(ID, Name): ID → Name (one ID determines one name).

4. Lossless and Lossy Decomposition

Lossless: original relation reconstructed by join. Example: R(A,B,C) → R1(A,B), R2(B,C). Lossy: extra tuples created, cannot recover original. Example: R(A,B,C) → R1(A,B), R2(A,C).

5. Short Note: B+ Tree and B Tree

B-Tree: data in internal+leaf nodes, faster for small datasets, more height. B+ Tree: data only in leaves, internal nodes store keys, leaves linked → better range queries.

6. Metadata and Data Dictionary

Metadata: data about data (table names, column types, constraints). Data Dictionary: central repository storing metadata (structures, privileges, relationships).

📘 Group-C (Long Answer – 15 Marks) – Preview
Full detailed answers for Group-C (15 marks)

✅ Topics covered: DELETE vs TRUNCATE vs DROP, anomalies, query optimization, decomposition, 3NF, B-Tree insertion, hashing, DDBMS, Web DBMS, etc.
Full solved answers available in continuation.

📌 For each 15-mark question, detailed explanations with examples, diagrams, and step-by-step derivations are provided in the complete solution set as per MAKAUT exam pattern.

📖 Exam-focused Summary

✔ Complete coverage of MAKAUT DBMS (Sem-6, 2022–23) – Groups A & B solved.
✔ Metadata, ALTER, NTFS, TCL, ACID, normalization, Armstrong’s axioms, functional dependency, lossless/lossy decomposition, B-Tree vs B+Tree, data dictionary.
✔ Group-C 15-mark answers available on request (DELETE vs TRUNCATE vs DROP, anomalies, query optimization, 3NF, B-Tree, hashing, distributed DBMS, etc.).

📌 Next: Detailed 15-mark solutions in full exam format (with examples, diagrams, and stepwise answers) can be provided immediately.