computer-science

name	computer-science
description	CBSE Grade 12 Computer Science (Python) — Full Syllabus Mastery (2026-27). Covers Computational Thinking, Networking, and Database Management (SQL). Target: 70/70 Theory + 30/30 Practical.

Computer Science — CBSE Grade 12 (PCMC)

Syllabus Blueprint (2026–27)

Unit	Title	Marks
I	Computational Thinking and Programming – 2	40
II	Computer Networks	10
III	Database Management (SQL)	20
Total	Theory Exam	70

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Unit I: Programming with Python (40 Marks) - The Giant

Key Concepts

• Functions: Scope (Global/Local), Parameter passing (Default, Positional, Keyword), Recursion.
• Data Structures: Stack (Push/Pop logic using lists), Queue (introductory).
• File Handling:
  • Text Files: read(), readline(), readlines(), write(), writelines().
  • Binary Files: pickle module (dump/load), Seek() and Tell() methods.
  • CSV Files: csv module (reader/writer/writerow).
• Python Libraries: Creating and importing modules.

High-Yield Code snippets

# Binary File Append
import pickle
def append_data(data):
    with open("data.dat", "ab") as f:
        pickle.dump(data, f)

# Stack Implementation
def push(stk, item):
    stk.append(item)
def pop(stk):
    if not stk: return "Underflow"
    return stk.pop()

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Unit II: Computer Networks (10 Marks)

Key Concepts

• Basics: Evolution, Switching techniques (Circuit/Packet).
• Transmission Media: Wired (Twisted pair, Coaxial, Optical fiber) vs Wireless (Infrared, Radio, Microwave, Satellite).
• Topology: Star, Bus, Tree, Mesh.
• Protocols: TCP/IP, HTTP, FTP, SMTP, POP3, DNS.
• Network Devices: RJ45, NIC, Modem, Hub, Switch, Router, Gateway.

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Unit III: Database Management (20 Marks)

Key Concepts

• Relational Model: Relation, Attribute, Tuple, Degree, Cardinality.
• SQL Commands:
  • DDL: CREATE, ALTER, DROP.
  • DML: SELECT, INSERT, UPDATE, DELETE.
• Constraints: PRIMARY KEY, NOT NULL, UNIQUE, DEFAULT, FOREIGN KEY.
• Aggregates: COUNT(), SUM(), AVG(), MIN(), MAX().
• Claus: WHERE, ORDER BY, GROUP BY, HAVING, DISTINCT.
• Joins: Cartesian product, Equi-Join, Natural Join.

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High-Yield Strategy (Target 495+)

1. The Python 40: Master File Handling (5-mark question) and Stack/Queue logic. Output questions from Ch 1 are guaranteed.
2. SQL Precision: One 5-mark question involves writing SQL queries for a given table. Master GROUP BY and HAVING.
3. Network Layout: A 5-mark Case Study involves suggesting a network layout (topology, server placement, device placement) for a company with multiple blocks.
4. Dry Runs: Practice tracing output for loops and recursion.

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Common Board Exam Traps

• Pickle Module: Forgetting to open binary files in rb or ab mode.
• CSV Headers: Forgetting to handle the newline character in CSV writing.
• SQL syntax: Confusing DELETE (DML) with DROP (DDL).
• Networking: Suggesting a "Switch" when a "Hub" is asked, or missing the distance-based topology logic.

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Answer Writing Framework

1. Code Snippets: Use proper indentation. Even on paper, show leading spaces.
2. Output Questions: Provide a Trace Table (Variable | Value) to prove your logic.
3. Networking Case Study: Draw the suggested topology and justify why you chose it (e.g., "Star topology is efficient for this block distance").
4. SQL: Write keywords in UPPERCASE for clarity.

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Internal Assessment (30 Marks)

• Lab Test: Python program + SQL query (7+5 Marks).
• Report File: 20+ Python programs + 5 SQL sets (7 Marks).
• Project: 8 Marks. Be ready to explain your logic in the Viva (5 Marks).