DBMS Fundamentals: Architecture, Data Models, and SQL Languages

1. DBMS – Introduction

Data

Data means raw facts and figures.

Example: 101, Vikas, CSE, 1st Year

Database

A database is an organized collection of related data that can be easily accessed, managed, and updated.

DBMS

DBMS (Database Management System) is software used to create, store, retrieve, update, and manage data in a database.

Examples: MySQL, Oracle, PostgreSQL, SQL Server.

Functions of DBMS

  • Data storage
  • Data retrieval
  • Data insertion and updating
  • Data security
  • Backup and recovery
  • Concurrency control
  • Integrity
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Data Link Layer: Framing, ARQ, HDLC, PPP, Channel Access and Ethernet Explained

Unit 2: Data Link Layer, Complete Notes with Solved PYQs

Your exam is today, so the ★ boxes (exam-ready answers) and the PYQ solutions come first in priority. Read the basics only if you have time.

One correction to the earlier numbers: the 1 Mbps / 20 ms question has two valid answers. The textbook method (Forouzan, which the paper’s wording follows) gives 5% and 75%. The formula Tₜ/(Tₜ+RTT) gives 4.76% and 71.4%. Write the textbook method in the exam and add the formula as a one-line remark.

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Complete JavaScript Roadmap and Topic-Wise Tutorial

JavaScript Complete Topic-Wise Explanation

1. JavaScript kya hai?

JavaScript ek programming language hai jo website ko interactive aur dynamic banati hai.

Simple example:

  • HTML → Website ka structure
  • CSS → Website ka design
  • JavaScript → Website ka behavior/functionality

Example: Button click karne par text change karna.

Click Me

Hello


2. JavaScript ko HTML me add karna

Internal JavaScript

External JavaScript

HTML:

script.js:

console.log("Hello JavaScript");

External JS real projects me commonly use hoti

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C++ Algorithms for Binary Search and Prefix Sums

C++ Competitive Programming Solutions

This document contains several C++ solutions for common algorithmic problems involving prefix sums, binary search, and matrix manipulation.

1. Prefix Sum and Lower Bound Algorithm

#include <bits/stdc++.h>
using namespace std;

int main() {
    int n;
    long long k;

    cin >> n >> k;

    vector<long long> pref(n + 1, 0);

    for (int i = 1; i <= n; i++) {
        long long x;
        cin >> x;
        pref[i] = pref[i - 1] 
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C++ Algorithms and Binary Search Implementation Codes

C++ Binary Search and Algorithms Collection

1. Binary Search Implementation

#include <iostream> 
using namespace std;
int main(){
    int n; 
    cin >> n;
    int a[100000];
    for (int i = 0; i < n; i++)
        cin >> a[i];
    int x;
    cin >> x;
    int l = 0, r = n - 1;
    while (l <= r) {
        int m = (l + r) / 2;
        if (a[m] == x) {
            cout << "Yes";
            return 0;
        }
        if (a[m] < x)
            l = m + 1;
     
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Altair Cheat Sheet Python: Data Visualization Reference

Altair Cheat Sheet Python

01 Build a chart


1. Import + general pattern

import altair as alt
chart = (
    alt.Chart(data).mark_…()
    .encode(x=…, y=…, color=…)
    .transform_…(…).properties(…)
    .interactive()
)

2. Choose a chart type

mark_bar   bars / aggregated comparison
mark_line   trends over an ordered axis
mark_circle   scatter plots
mark_area   filled trends / totals
mark_rect   heat maps
mark_arc   pie or donut charts
mark_boxplot   distribution summaries
mark_geoshape

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