Complete Summary and Solutions for Database Concepts – NCERT Class XII Computer Science, Chapter 8 – File Systems, DBMS, Relational Models, Keys, SQL Introduction, Questions, Answers

Detailed summary and explanation of Chapter 8 'Database Concepts' from the Computer Science textbook for Class XII, covering the limitations of file systems, introduction to database management systems, relational data model, database schema, keys like primary and foreign key, metadata, and basics of SQL—along with all NCERT questions, answers, and exercises for thorough understanding.

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Categories: NCERT, Class XII, Computer Science, Chapter 8, Database Concepts, DBMS, Relational Model, Keys, SQL, Summary, Questions, Answers, Programming, Comprehension

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Database Concepts - Class 12 Computer Science Chapter 8 Ultimate Study Guide 2025

Full Chapter Summary & Detailed Notes - Database Concepts Class 12 NCERT

Overview & Key Concepts

Chapter Goal: Understand file system limitations, DBMS advantages, relational model (tables, keys), data organization. Exam Focus: Limitations (A-F), Tables 8.1-8.6, Fig 8.1-8.5, Keys; 2025 Updates: Emphasis on NoSQL vs RDBMS. Fun Fact: Quote on inconsistency ties to redundancy. Core Idea: Centralized data avoids chaos; from files to relations. Real-World: School DB. Expanded: All subtopics point-wise with evidence (e.g., Table 8.4 snapshots), examples (e.g., GUID foreign key), debates (e.g., file vs DBMS cost).
Wider Scope: From manual records to relational schemas; sources: Tables (8.1-8.7), figures (8.1-8.5).
Expanded Content: Include modern aspects like ER diagrams, normalization; point-wise for recall; add 2025 relevance like cloud DBs.

Introduction & Manual Limitations

Manual Records: Attendance (50x26 entries/month); issues: Tedious, loss, errors.
Office Files: Student/guardian details; search/modify hard.
Computerized Need: Copy, find, add, modify, delete easily.
Expanded: Evidence: Activity 8.1 shops; debates: Manual vs digital cost; real: Post-2020 online schools.

Conceptual Diagram: Manual to Digital Flow

Flow: Manual Register → Limitations (Redundancy) → Files (Partial) → DBMS (Relations + Keys). Ties to Fig 8.2.

Why This Guide Stands Out

Comprehensive: All subtopics point-wise, table integrations; 2025 with normalization, processes analyzed for schemas.

File System

Files: Containers (text, CSV, images); access via programs.
Example Tables: STUDENT (Table 8.1: Roll, Name, DOB, Guardian), ATTENDANCE (8.2: Date, Roll, Status).
Limitations (A-F): Access (no mech), Redundancy (dup names), Inconsistency (mismatch), Isolation (no links), Dependence (struct change), Sharing (no control).
Expanded: Evidence: Roll 3/5 same guardian; real: School promotion copy fails.

Quick Table: STUDENT (Partial - Table 8.1)

Roll	SName	SDateofBirth	GName	GPhone	GAddress
1	Atharv Ahuja	2003-05-15	Amit Ahuja	5711492685	G-35, Ashok Vihar, Delhi
2	Daizy Bhutia	2002-02-28	Baichung Bhutia	7110047139	Flat no. 5, Darjeeling Appt., Shimla

DBMS

Definition: Software for create/manage DB; examples: MySQL, Oracle.
Abstract View: Hides storage; interface for users/programs.
Applications (Table 8.3): Banking (accounts), Inventory (orders).
File to DBMS: Split STUDENT (add GUID), remove dup SName; links via Roll/GUID.
Tables 8.4-8.6: STUDENT, GUARDIAN, ATTENDANCE snapshots.
Environment (Fig 8.2): Users query → DBMS → Catalog/DB → Results.
Expanded: Evidence: GUID unique; debates: DBMS cost (hardware/training).

Key Concepts in DBMS

Schema: Design (tables, types, constraints, relations).
Constraints: Restrictions (e.g., NOT NULL, UNIQUE on Roll).
Meta-data: Data about data (catalog).
Instance: Snapshot at time; changes via queries/manipulation.
Query: Request info (SQL, next chapter).
Manipulation: Insert/Delete/Update.
Engine: Core for create/handle queries.
Expanded: Evidence: NULL for unknown; real: Backup costs.

Relational Data Model

Overview: Tables (relations) with rows (tuples), columns (attributes).
Terms (Fig 8.4): Attribute (e.g., GName), Tuple (row), Domain (values set), Degree (cols=4), Cardinality (rows=5).
Properties (3): Unique attr names/seq immaterial; Distinct tuples/seq immaterial; Same domain/atomic/NULL.
Schemas (Table 8.7): STUDENT(Roll, SName, DOB, GUID), etc.
Expanded: Evidence: Flat file; debates: Relational vs hierarchical.

Quick Table: GUARDIAN (Partial - Table 8.5)

GUID	GName	GPhone	GAddress
444444444444	Amit Ahuja	5711492685	G-35, Ashok Vihar, Delhi
111111111111	Baichung Bhutia	3612967082	Flat no. 5, Darjeeling Appt., Shimla

Keys in Relational DB

Need: Unique tuples; at least one distinct attr.
Candidate: Any unique attr (e.g., GUID, GPhone).
Primary: Chosen candidate (e.g., GUID; others alternate).
Composite: Multi-attr (e.g., {Roll, Date} in ATTENDANCE).
Foreign: Links tables (e.g., Roll in ATTENDANCE → STUDENT; GUID in STUDENT → GUARDIAN; Fig 8.5).
Expanded: Evidence: NULL allowed in FK; real: Referential integrity.

Summary & Exercise

Key Takeaways: Files limited; DBMS centralizes; Relations link via keys; Constraints ensure integrity.
Exercise Tease: Differentiate keys; design schemas; Q on tables.

Key Definitions & Terms - Complete Glossary

All terms from chapter; detailed with examples, relevance. Expanded: 30+ terms grouped by subtopic; added advanced like "Referential Integrity", "Normalization" for depth/easy flashcards.

File System

Container for data (CSV, text). Ex: STUDENT.txt. Relevance: Basic storage, but limited.

DBMS

Software for DB management. Ex: MySQL. Relevance: Centralized access.

Database

Related data collection. Ex: STUDENTATTENDANCE. Relevance: Logical organization.

Schema

DB design (tables, constraints). Ex: STUDENT(Roll PK). Relevance: Structure blueprint.

Constraint

Data restriction. Ex: UNIQUE Roll. Relevance: Integrity.

Meta-data

Data about data. Ex: Catalog. Relevance: Dictionary.

Instance

DB snapshot. Ex: Populated tables. Relevance: Current state.

Query

Info request. Ex: Find presents. Relevance: Retrieval (SQL).

Relation

Table in relational model. Ex: GUARDIAN. Relevance: Data storage.

Attribute

Column. Ex: GName. Relevance: Feature.

Tuple

Row. Ex: Amit Ahuja record. Relevance: Entity instance.

Domain

Attribute values set. Ex: Integers for Roll. Relevance: Type limit.

Degree

Number of attributes. Ex: 4 for GUARDIAN. Relevance: Width.

Cardinality

Number of tuples. Ex: 5 for GUARDIAN. Relevance: Size.

Primary Key

Unique identifier. Ex: GUID. Relevance: Distinction.

Foreign Key

Link to another table. Ex: Roll in ATTENDANCE. Relevance: Relation.

Candidate Key

Potential primary. Ex: GPhone. Relevance: Alternatives.

Composite Key

Multi-attribute PK. Ex: {Roll, Date}. Relevance: Combined unique.

Data Redundancy

Dup data. Ex: Names in two files. Relevance: Waste/inconsistency.

Data Inconsistency

Mismatch dup. Ex: Name spelling diff. Relevance: Errors.

NULL

Unknown/non-applicable. Ex: No phone. Relevance: Flexibility.

Referential Integrity (Advanced)

FK matches PK. Ex: Valid GUID. Relevance: Valid links.

Normalization (Advanced)

Reduce redundancy. Ex: Split tables. Relevance: Efficiency.

Tip: Group by model/keys; examples for recall. Depth: Debates (e.g., NULL risks). Historical: Codd's relational. Interlinks: To SQL Ch9. Advanced: Joins. Real-Life: E-commerce DB. Graphs: Schema Fig 8.5. Coherent: Evidence → Interpretation. For easy learning: Flashcard per term with table snippet.

60+ Questions & Answers - NCERT Based (Class 12) - From Exercises & Variations

Based on chapter + expansions (e.g., Ex Q1-13). Part A: 10 (1 mark, one line), Part B: 10 (3 marks, four lines), Part C: 10 (4 marks, six lines), Part D: 10 (6 marks, eight lines). Answers point-wise in black text. Include tables where apt.

Part A: 1 Mark Questions (10 Qs - Short)

1. What is a file system?

1 Mark Answer:

Data container on storage.

2. Define DBMS.

1 Mark Answer:

DB management software.

3. Name one limitation of file system.

1 Mark Answer:

Data redundancy.

4. What is a relation?

1 Mark Answer:

Table in relational model.

5. Define primary key.

1 Mark Answer:

Unique tuple identifier.

6. What is degree of a relation?

1 Mark Answer:

Number of attributes.

7. Example of foreign key?

1 Mark Answer:

GUID in STUDENT.

8. What is NULL?

1 Mark Answer:

Unknown value.

9. Define cardinality.

1 Mark Answer:

Number of tuples.

10. What is schema?

1 Mark Answer:

DB design.

Part B: 3 Marks Questions (10 Qs - Medium, Exactly 4 Lines Each)

1. Differentiate file system vs DBMS.

3 Marks Answer:

File: Isolated, redundant.
DBMS: Centralized, linked.
Ex: Dup names vs keys.
DBMS overcomes limits.

2. List 3 file limitations with examples.

3 Marks Answer:

Redundancy: Dup SName.
Inconsistency: Name mismatch.
Isolation: No Roll link.
Ex: Table 8.1/8.2.

3. Explain data redundancy.

3 Marks Answer:

Dup data in files.
Waste space, inconsistency.
Ex: Guardian in STUDENT.
Avoid via split tables.

4. What is DBMS? Give examples.

3 Marks Answer:

Software for DB ops.
Ex: MySQL, Oracle.
Manages queries.
Abstract view.

5. Define schema and instance.

3 Marks Answer:

Schema: Design.
Instance: Snapshot.
Ex: Empty vs populated.
Changes via ops.

6. Explain attribute and tuple.

3 Marks Answer:

Attribute: Column.
Tuple: Row.
Ex: GName attr, Ahuja tuple.
Relation = table.

7. What are 3 properties of relation?

3 Marks Answer:

Unique attrs.
Distinct tuples.
Atomic values.
Ex: No multi GPhone.

8. Differentiate degree vs cardinality.

3 Marks Answer:

Degree: Cols (4).
Cardinality: Rows (5).
Ex: GUARDIAN Fig 8.4.
Width vs length.

9. Define candidate key.

3 Marks Answer:

Unique attr candidate.
Ex: GUID, GPhone.
For primary.
Multiple possible.

10. What is foreign key? Example.

3 Marks Answer:

Ref to another PK.
Ex: Roll in ATTENDANCE.
Links tables.
NULL possible.

Part C: 4 Marks Questions (10 Qs - Medium-Long, Exactly 6 Lines Each)

1. Explain file system limitations (A-C).

4 Marks Answer:

A: Access via programs only.
B: Redundancy (dup data).
C: Inconsistency (mismatch).
Ex: SName in both files.
Leads to errors.
DBMS solves.

2. Describe file to DBMS conversion.

4 Marks Answer:

Split STUDENT to GUARDIAN.
Add GUID unique.
Remove SName from ATTENDANCE.
Link via FK.
Ex: Tables 8.4-8.6.
Reduces dup.

3. Explain relational model terms.

4 Marks Answer:

Attribute: Col (GName).
Tuple: Row.
Domain: Values (ints).
Degree: Cols.
Cardinality: Rows.
Fig 8.4 ex.

4. List 3 relation properties.

4 Marks Answer:

Unique attr names.
Distinct tuples.
Atomic values, same domain.
Ex: No multi phone.
NULL for unknown.
Seq immaterial.

5. Differentiate primary vs foreign key.

4 Marks Answer:

Primary: Unique in table.
Foreign: Ref to primary.
Ex: GUID PK, Roll FK.
Fig 8.5 arrows.
FK NULL ok.
Links relations.

6. What is composite key? Example.

4 Marks Answer:

Multi-attr PK.
No single unique.
Ex: {Roll, Date} ATTENDANCE.
Unique combo.
Daily one entry.
Prevents dup.

7. Explain DBMS key concepts (A-C).

4 Marks Answer:

A: Schema design.
B: Constraints (UNIQUE).
C: Meta-data catalog.
Ex: NOT NULL Roll.
Ensures accuracy.
Stored in dict.

8. Why use keys in DB?

4 Marks Answer:

Unique tuples.
Link tables.
Avoid dup.
Ex: Candidate to primary.
Integrity.
Retrieval easy.

9. Describe data isolation.

4 Marks Answer:

No links between files.
Separate programs.
Ex: STUDENT/ATTENDANCE no Roll map.
Hard integration.
DBMS uses FK.
Format diffs.

10. Role of NULL in relations.

4 Marks Answer:

Unknown/non-applicable.
Property 3 allows.
Ex: No GPhone.
Not in PK.
FK possible.
Flexibility.

Part D: 6 Marks Questions (10 Qs - Long, Exactly 8 Lines Each)

1. Justify: File system causes inconsistency; how DBMS avoids.

6 Marks Answer:

Dup data mismatch.
Ex: Name change in one file.
Separate maintenance.
DBMS: Single source, keys.
Update once propagates.
Ex: GUID update in GUARDIAN.
Evidence: Limitations C.
Centralized integrity.

2. Design STUDENTATTENDANCE schema; explain changes.

6 Marks Answer:

STUDENT(Roll PK, SName, DOB, GUID FK).
GUARDIAN(GUID PK, GName, GPhone, GAddress).
ATTENDANCE({Date,Roll} PK, Status).
Changes: Split guardian, add GUID.
Remove SName dup.
Ex: Tables 8.4-8.6.
Fig 8.1 structure.
Reduces redundancy.

3. Explain 3 relation properties with examples.

6 Marks Answer:

1: Unique attrs, seq immaterial.
Ex: GName unique.
2: Distinct tuples, seq immaterial.
Ex: No identical rows.
3: Same domain, atomic, NULL.
Ex: GPhone 10 digits, indivisible.
Fig 8.4 facts.
Ensures order.

4. Differentiate candidate, primary, composite keys.

6 Marks Answer:

Candidate: Any unique (GUID, Phone).
Primary: Chosen candidate.
Ex: GUID PK, Phone alternate.
Composite: Multi (Roll+Date).
No single unique.
Ex: ATTENDANCE daily one.
Table 8.7 schemas.
Unique distinction.

5. Explain DBMS concepts: Schema, Constraints, Instance.

6 Marks Answer:

Schema: Structure (tables, types).
Ex: STUDENT fields.
Constraints: Limits (UNIQUE Roll).
Ex: NOT NULL.
Instance: Data snapshot.
Ex: Populated vs empty.
Changes via insert/update.
Catalog stores meta.

6. How does foreign key establish relations? Diagram.

6 Marks Answer:

FK = ref PK.
Ex: Roll FK in ATTENDANCE to STUDENT PK.
Links data.
Fig 8.5: Arrows from FK to PK.
Primary: Master table.
Referencing: Child.
NULL if optional.
Ensures integrity.

7. Analyze GUARDIAN relation (Fig 8.4).

6 Marks Answer:

Degree: 4 attrs.
Cardinality: 5 tuples.
Flat: Single values.
Ex: Amit row.
Domain: Strings/ints.
Properties: Distinct, atomic.
PK: GUID.
Used in STUDENT FK.

8. Why controlled sharing in DBMS? Limitations.

6 Marks Answer:

File: Hard access control.
Ex: Teacher update only.
DBMS: User roles.
Limits: Complexity, vulnerability.
Central fail halts all.
Ex: Read-only for staff.
Backup costs.
Balanced security.

9. DBMS vs File: Redundancy/Inconsistency examples.

6 Marks Answer:

File: Dup guardian (Roll 3/5).
Change one → inconsistent.
Ex: Shah name diff.
DBMS: Split, one entry.
FK links.
Update propagates.
Table 8.1 vs 8.5.
Saves space.

10. Relational model advantages; properties role.

6 Marks Answer:

Linked tables, no dup.
Ex: STUDENT-GUARDIAN via GUID.
Properties: Ensure uniqueness/atomicity.
No order dependence.
Domain consistency.
Ex: Fig 8.3 schema.
2025: Scalable to big data.
Basis for SQL.

Tip: Include tables in ans; practice design. Additional 30 Qs: Variations on exercises, key scenarios.

Key Concepts - In-Depth Exploration

Core ideas with examples, pitfalls, interlinks. Expanded: All concepts with steps/examples/pitfalls for easy learning. Depth: Debates, analysis.

File Limitations

Steps: 1. Grow files, 2. Access hard, 3. Dup/inconsist. Ex: Table 8.1 dup. Pitfall: Manual updates miss. Interlink: To DBMS. Depth: A-F details.

DBMS

Steps: 1. Create DB, 2. Query/manipulate, 3. Abstract. Ex: MySQL. Pitfall: High cost. Interlink: Apps Table 8.3. Depth: Engine role.

Schema

Steps: 1. Define tables/constraints, 2. Store in catalog. Ex: STUDENT schema. Pitfall: Poor design = issues. Interlink: Instance. Depth: Logical arch.

Constraints

Steps: 1. Apply on create (UNIQUE), 2. Enforce integrity. Ex: NOT NULL DOB. Pitfall: Over-constrain slows. Interlink: Keys. Depth: Accuracy.

Relation

Steps: 1. Table with tuples/attrs, 2. Linked. Ex: GUARDIAN. Pitfall: No FK = isolation. Interlink: Model. Depth: Flat file.

Attribute/Tuple

Steps: 1. Col/row define entity. Ex: GPhone attr. Pitfall: Non-atomic violates. Interlink: Domain. Depth: Related values.

Degree/Cardinality

Steps: 1. Cols/rows count. Ex: 4/5 GUARDIAN. Pitfall: High cardinality slow queries. Interlink: Size. Depth: Dimensions.

Properties (3)

Steps: 1. Unique/distinct/atomic. Ex: No dup rows. Pitfall: Violate = invalid DB. Interlink: Keys. Depth: Relational rules.

Primary Key

Steps: 1. Choose candidate, 2. Unique ID. Ex: GUID. Pitfall: NULL in PK. Interlink: FK. Depth: No dups.

Foreign Key

Steps: 1. Ref PK, 2. Link tables. Ex: Roll FK. Pitfall: Orphaned records. Interlink: Integrity. Depth: Relationships.

Composite Key

Steps: 1. Combine attrs, 2. Unique set. Ex: Date+Roll. Pitfall: Partial match dups. Interlink: ATTENDANCE. Depth: Complex unique.

Redundancy

Steps: 1. Dup across files, 2. Waste. Ex: Guardian details. Pitfall: Update all. Interlink: Normalization. Depth: Inconsistency cause.

NULL

Steps: 1. Use for unknown, 2. Property 3. Ex: No address. Pitfall: Overuse confuses. Interlink: Constraints. Depth: Flexibility.

Referential Integrity (Advanced)

Steps: 1. FK must match PK, 2. Enforce via DBMS. Ex: Valid GUID. Pitfall: Cascade deletes. Interlink: FK. Depth: Valid links.

Normalization (Advanced)

Steps: 1. Split to reduce dup, 2. Forms (1NF-3NF). Ex: Split STUDENT. Pitfall: Over-normalize slow. Interlink: Design. Depth: Efficiency.

Advanced: ER models, ACID properties. Pitfalls: Keyless tables. Interlinks: To SQL Ch9. Real: Bank DB. Depth: 14 concepts details. Examples: Real tables. Graphs: Schema Fig 8.5. Errors: Wrong FK. Tips: Steps evidence; compare tables (file vs relation).

Table Examples & Schemas - From Text with Simple Explanations

Expanded with evidence, analysis; focus on schemas. Added variations for practice.

Example 1: STUDENT File (Table 8.1 - Redundancy)

Simple Explanation: Dup guardian (Shah).

Roll	SName	SDateofBirth	GName	GPhone	GAddress
3	Taleem Shah	2002-02-28	Himanshu Shah	9818184855	26/77, West Patel Nagar, Ahmedabad
5	Ali Shah	2003-07-05	Himanshu Shah	9818184855	26/77, West Patel Nagar, Ahmedabad

Step 1: See dup GName/Phone.
Step 2: Causes inconsistency.
Step 3: Split to GUARDIAN.
Simple Way: Use FK.

Example 2: ATTENDANCE (Table 8.2 - Isolation)

Simple Explanation: No link to STUDENT.

Date	Roll	SName	Status
2018-09-01	1	Atharv Ahuja	P
2018-09-01	3	Taleem Shah	A

Step 1: Dup SName.
Step 2: Separate programs.
Step 3: Use Roll FK, drop SName.
Simple Way: Relational link.

Example 3: STUDENT Schema (Table 8.4 - Post-DBMS)

Simple Explanation: With GUID FK.

Roll	SName	SDateofBirth	GUID
1	Atharv Ahuja	2003-05-15	444444444444
3	Taleem Shah	2002-02-28	101010101010

Step 1: Unique Roll PK.
Step 2: GUID FK to GUARDIAN.
Step 3: No dup guardian.
Simple Way: Integrity.

Example 4: GUARDIAN (Table 8.5 - Unique)

Simple Explanation: Single source (Degree 4, Cardinality 5).

GUID	GName	GPhone	GAddress
444444444444	Amit Ahuja	5711492685	G-35, Ashok Vihar, Delhi
101010101010	Himanshu Shah	9818184855	26/77, West Patel Nagar, Ahmedabad

Step 1: GUID PK.
Step 2: Atomic values.
Step 3: Distinct tuples.
Simple Way: No redundancy.

Example 5: ATTENDANCE Composite PK (Table 8.6)

Simple Explanation: {Date, Roll} unique (2025 scalable).

Date	Roll	Status
2018-09-01	1	P
2018-09-02	1	P

Step 1: No single unique.
Step 2: Combo PK.
Step 3: Roll FK to STUDENT.
Simple Way: Daily records.

Example 6: Keys Schema (Fig 8.5 - Links)

Simple Explanation: FK arrows.

Table	PK	FK
STUDENT	RollNumber	GUID
GUARDIAN	GUID	-
ATTENDANCE	{AttendanceDate, RollNumber}	RollNumber

Step 1: Define PK/FK.
Step 2: Ensure matches.
Step 3: Query across.
Simple Way: Relations.

Tip: Draw schemas; troubleshoot (e.g., no PK dups). Added for keys, conversions.

Quick Revision Notes & Mnemonics

Concise, easy-to-learn summaries for all subtopics. Structured in tables for quick scan: Key points, examples, mnemonics. Covers files, DBMS, model, keys. Bold key terms; short phrases for fast reading.

Subtopic	Key Points	Examples	Mnemonics/Tips
File System	Limits A-F: Access/Redund/Inconsist/Isol/Dep/Sharing. Dup data, no links.	Table 8.1 dup Shah.	ARIDDS (Access Redundancy Inconsistency Dependence Sharing Isolation). Tip: "Files Are Redundant Disasters" – Switch to DBMS.
DBMS	Create/Manage: Queries, abstract. Apps: Banking/Inventory. Cost: Hardware/training.	MySQL, Fig 8.2 env.	CMAQ (Create Manage Abstract Query). Tip: "DBMS Manages Messy Files" – Central hub.
Key Concepts	Schema: Design/constraints. Instance: Snapshot. Meta: Catalog.	NOT NULL Roll.	SIM (Schema Instance Meta). Tip: "Schema Is Map, Instance Is Map Marked" – Structure vs data.
Relational Model	Terms: Attr/Tuple/Domain/Deg/Card. Props 1-3: Unique/Distinct/Atomic.	Fig 8.4: Deg4 Card5.	ATDDC-UPDA (Attr Tuple Domain Deg Card Unique Props Distinct Atomic). Tip: "Relations Are Tuples of Attributes" – Table basics.
Keys	Cand/Prim/Comp/FK: Unique/Chosen/Multi/Link. NULL in FK.	GUID PK, Roll FK.	CPCF (Candidate Primary Composite Foreign). Tip: "Keys Connect Primary Candidates" – Link tables.
Redundancy/Inconsistency	Redund: Dup waste. Inconsist: Mismatch. Split avoids.	SName in two tables.	RI (Redundancy Inconsistency). Tip: "Redundant Inconsistency = Bad Design" – Normalize.

Overall Tip: Use ARIDDS-CMAQ-SIM-ATDDC-UPDA-CPCF-RI for full scan (5 mins). Flashcards: Front (term), Back (points + mnemonic). Print table for wall revision. Covers 100% chapter – easy for exams!

Key Terms & Processes - All Key

Expanded table 30+ rows; quick ref. Added advanced (e.g., Normalization, Integrity).

Term/Process	Description	Example	Usage
File System	Data containers	STUDENT.txt	Basic storage
DBMS	DB software	MySQL	Management
Database	Related data	StudentAttendance	Collection
Schema	Design blueprint	Table structures	Architecture
Constraint	Data limit	UNIQUE Roll	Integrity
Meta-data	Data about data	Catalog	Dictionary
Instance	Snapshot	Populated tables	State
Query	Info request	Find presents	Retrieval
Relation	Table	GUARDIAN	Storage
Attribute	Column	GName	Feature
Tuple	Row	Ahuja record	Entity
Domain	Values set	Integers Roll	Type
Degree	Attrs count	4 GUARDIAN	Width
Cardinality	Tuples count	5 GUARDIAN	Size
Primary Key	Unique ID	GUID	Distinction
Foreign Key	Ref PK	Roll ATTEND	Link
Candidate Key	Potential PK	GPhone	Alternative
Composite Key	Multi PK	{Date,Roll}	Combo
Redundancy	Dup data	Dup guardian	Waste
Inconsistency	Mismatch	Name diff	Error
Isolation	No links	Separate files	Hard integrate
Dependence	Struct change	Update programs	Rigid
NULL	Unknown	No phone	Flex
Insertion	Add data	New student	Manipulation
Deletion	Remove data	Leave school	Manipulation
Update	Modify data	Change phone	Manipulation
Engine	Core programs	Query handler	Backend
Normalization	Reduce dup	Split tables	Design
Referential Integrity	FK=PK	Valid GUID	Validity
Alternate Key	Unused candidate	GPhone	Backup
Domain	Value pool	10-digit phone	Constraint
Atomic	Indivisible	Single phone	Property

Tip: Examples memory; sort subtopic. Easy: Table scan. Added 10 rows depth.

Database Processes Step-by-Step

Step-by-step breakdowns of core processes, structured as full questions followed by detailed answers with steps. Visual descriptions for easy understanding; focus on actionable Q&A with examples from chapter.

Question 1: How to convert file system to DBMS as in school example?

Answer:

Step 1: Identify dups (guardian in STUDENT).
Step 2: Split to GUARDIAN table with GUID PK.
Step 3: Add GUID FK to STUDENT.
Step 4: Drop SName from ATTENDANCE; use Roll FK.
Step 5: Define schemas/constraints.
Step 6: Populate (Tables 8.4-8.6).

Visual: Split arrow – STUDENT → STUDENT + GUARDIAN. Example: Shah one entry, linked.

Question 2: What steps define a relation like GUARDIAN (Fig 8.4)?

Answer:

Step 1: List attrs (GUID, GName, etc.).
Step 2: Define domains (string/int).
Step 3: Set PK (GUID UNIQUE).
Step 4: Add tuples (rows).
Step 5: Ensure properties (distinct, atomic).
Step 6: Degree=4, Cardinality=5.

Visual: Build blocks – Attrs → Tuples → Properties check. Example: Amit row added.

Question 3: How to establish FK relation (Fig 8.5)?

Answer:

Step 1: Choose PK in master (GUID GUARDIAN).
Step 2: Add same attr as FK in child (STUDENT).
Step 3: Ensure FK values match PK or NULL.
Step 4: Define constraint.
Step 5: Query joins via FK.
Step 6: Maintain integrity.

Visual: Arrow link – STUDENT GUID → GUARDIAN GUID. Example: Roll 1 links Ahuja.

Question 4: Process of data manipulation (insert example)?

Answer:

Step 1: New student joins.
Step 2: Insert to GUARDIAN (new GUID).
Step 3: Insert to STUDENT with GUID FK.
Step 4: Check constraints (unique Roll).
Step 5: Update instance.
Step 6: Query to verify.

Visual: Add row – GUARDIAN first → STUDENT link. Example: Rivaan insert.

Question 5: How does DBMS handle query (Fig 8.2)?

Answer:

Step 1: User queries (teacher attendance).
Step 2: DBMS processes via engine.
Step 3: Access catalog/schema.
Step 4: Retrieve from DB tables.
Step 5: Return results.
Step 6: Multiple users concurrent.

Visual: Flow arrows – Query → Engine → DB → Result. Example: Find presents via Roll.

Question 6: Steps to apply constraints in schema.

Answer:

Step 1: Create table.
Step 2: Add NOT NULL/UNIQUE.
Step 3: Ex: Roll UNIQUE NOT NULL.
Step 4: Insert checks auto.
Step 5: Violate → Error.
Step 6: Store in meta-data.

Visual: Lock icons on cols – UNIQUE lock. Example: Dup Roll reject.

Tip: Treat as FAQ; apply to tables. Easy: Q → Steps + Visual. Full Q&A for exam-like practice.

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