Search – Lazy IITians Viva Prep

See reviews Level3_43 MAD1 Level 3

Aug 14, 2026

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1

The same as mentioned in the response sheet.

Times asked 2

Official solution

SimpleViva wrap-up hai. Short thanks + confirm submission ZIP latest hai.
2
Infact, lesser.

Times asked 2
Official solution

SimpleServer-Sent Events: server → browser one-way stream (text/event-stream). WebSocket full duplex hai; SSE simpler notifications ke liye.
Example
```
# client
const es = new EventSource('/stream');
es.onmessage = (e) => console.log(e.data);
```
3
Run through the app

Times asked 2
Official solution

Simplevenv activate → dependencies → DB create/migrate → flask run. Browser pe localhost dikhao.
Example
```
python -m venv .venv
source .venv/bin/activate
pip install -r requirements.txt
flask run
```
4

DOM

Times asked 2

Official solution

SimpleDOM HTML tree. JS nodes change. Vue Virtual DOM ke through, direct kam.
Manipulation innerHTML vs Vue data. Remove CSS class = rules gone layout may collapse.
Pehle 1-line definition, phir related MAD2 layer (Vue SFC / Flask route / models.py / tasks.py / Redis).
4-line formula: input kahan se aaya, auth/validation kaunsa, DB ya cache ya Celery, kya return.
Related mix mat karo — cache ≠ Celery, authentication ≠ authorization, v-if ≠ v-show, Beat ≠ Worker. Follow-up ke liye ek difference ready rakho.
Project example: Inspect Elements. Vue devtools.
5
What changes to make in models to incorporate favourite songs(add a new favourites table)

Times asked 2
Official solution

Simplemodels.py = har table ki class: columns, PK/FK, relationships. Yeh Model layer hai.
Suggested flow1) Classes list karo
2) Har table ka kaam 1 line
3) Relationships (1-M / M-M)
4) Constraints (unique, nullable)
Example
```
class Lot(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(80), nullable=False)
    spots = db.relationship('Spot', backref='lot', lazy=True)
```
6
Difference b/w session and cookies

Times asked 1
Official solution

SimpleMAD1 mein usually session-based auth: login pe session['user_id'], har request pe verify.
Example
```
session['user_id'] = user.id
uid = session.get('user_id')
user = User.query.get(uid)
```
Viva tipSECRET_KEY set karo warna session insecure. logout pe session.clear().

See reviews Level3_24 MAD1 Level 3

Aug 14, 2026

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1
Ask me to change the background Colour of Home page!

Times asked 2
Official solution

SimpleLive UI change: relevant CSS/HTML template kholo — color, margin, flex, bootstrap class. Save + hard refresh.
Example
```
/* button red */
.btn-primary { background: red; }

/* center navbar item */
.navbar { justify-content: center; }
```
Viva tipDevTools se pehle try, phir file mein permanent change.
2
Ask me to add background image in user dashboard!

Times asked 2
Official solution

SimpleLive UI change: relevant CSS/HTML template kholo — color, margin, flex, bootstrap class. Save + hard refresh.
Example
```
/* button red */
.btn-primary { background: red; }

/* center navbar item */
.navbar { justify-content: center; }
```
Viva tipDevTools se pehle try, phir file mein permanent change.
3
The Navbar you have on the top, put it in the footer section ( i am getting some error while doing this so he give me enough time to do, also ask me to take help from internet )

Times asked 2
Official solution

SimpleLive UI change: relevant CSS/HTML template kholo — color, margin, flex, bootstrap class. Save + hard refresh.
Example
```
/* button red */
.btn-primary { background: red; }

/* center navbar item */
.navbar { justify-content: center; }
```
Viva tipDevTools se pehle try, phir file mein permanent change.
4

What is JavaScript?

Times asked 1

Official solution

SimpleJavaScript browser/Node pe chalta hai — DOM, events, fetch/axios. MAD1 mein thoda JS; MAD2 mein Vue JS pe.

See reviews Level3_11 MAD1 Level 3

Aug 14, 2026

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1

Questions(I remember):

Times asked 2

Official solution

SimpleViva wrap-up hai. Short thanks + confirm submission ZIP latest hai.
2

Internal vs inline css

Times asked 2

Official solution

SimpleUngli rakhe to 4-line formula — panic ki jagah structure.
1) File ka role: model / Flask route / Vue SFC / celery task / config
2) Input kahan: JSON, params, token, props, $route
3) Kya kaam: query, cache, validation, .delay()
4) Output: jsonify, this.items, email, redirect
Unknown keyword: import, decorator, if, commit — har ka reason. Bluff mat.
Suggested flow1) Kaunsi layer?
2) Input?
3) DB/cache/task?
4) Response/UI?
Project example: Booking POST: jwt, seats check, commit, 201, Vue list push.
Viva tipUnknown keyword: import, decorator, if, commit — har ka reason. Panic mat.
3
Left join

Times asked 2
Official solution

SimpleJOIN related tables ek result mein. Inner = match only; left = left side sab + match.
Example
```
db.session.query(Booking, User).join(User).filter(User.id == uid).all()
```
4
how you implemented search functionality

Times asked 2
Official solution

SimpleSearch: form/query param → ilike filter → results template.
Example
```
q = request.args.get('q', '').strip()
lots = Lot.query.filter(Lot.name.ilike(f'%{q}%')).all()
```
5
Explain relationship between book and category tables

Times asked 2
Official solution

Simpledb.relationship se object graph: lot.spots, booking.user. backref reverse side auto deta hai.
Example
```
spots = db.relationship('Spot', backref='lot', cascade='all, delete-orphan')
```

See reviews Level3_24 MAD1 Level 1

Aug 14, 2026

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1
1 - introduce me to you app.

Times asked 3
Official solution

Simple30 second: naam, degree, project kya hai, stack (Flask + Jinja + SQLAlchemy + SQLite).
Example
```
Main Priya, IITM BS. MAD1 mein parking/ticket app — Flask backend, Jinja templates, session login, SQLite.
```
2
2 -: change button color to red

Times asked 1
Official solution

SimpleLive UI change: relevant CSS/HTML template kholo — color, margin, flex, bootstrap class. Save + hard refresh.
Example
```
/* button red */
.btn-primary { background: red; }

/* center navbar item */
.navbar { justify-content: center; }
```
Viva tipDevTools se pehle try, phir file mein permanent change.
3
change bg color of app

Times asked 3
Official solution

SimpleLive UI change: relevant CSS/HTML template kholo — color, margin, flex, bootstrap class. Save + hard refresh.
Example
```
/* button red */
.btn-primary { background: red; }

/* center navbar item */
.navbar { justify-content: center; }
```
Viva tipDevTools se pehle try, phir file mein permanent change.
4
push nav bar to bottom

Times asked 3
Official solution

SimpleLive UI change: relevant CSS/HTML template kholo — color, margin, flex, bootstrap class. Save + hard refresh.
Example
```
/* button red */
.btn-primary { background: red; }

/* center navbar item */
.navbar { justify-content: center; }
```
Viva tipDevTools se pehle try, phir file mein permanent change.
5
change appearance of page

Times asked 3
Official solution

SimpleLive UI change: relevant CSS/HTML template kholo — color, margin, flex, bootstrap class. Save + hard refresh.
Example
```
/* button red */
.btn-primary { background: red; }

/* center navbar item */
.navbar { justify-content: center; }
```
Viva tipDevTools se pehle try, phir file mein permanent change.
6

3 - questions:

Times asked 1

Official solution

SimpleViva wrap-up hai. Short thanks + confirm submission ZIP latest hai.
7
vue

Times asked 2
Official solution

SimpleVue = UI ka smart assistant. Data badlo, screen khud update. MAD1 Jinja har click pe naya HTML.
Progressive frontend framework. Components, reactivity, directives.
MAD2 SPA: ek index.html, Vue Router pages, Flask sirf JSON.
Fayde: easy, SFC, docs. Vs React: templates HTML-like, course sikhata hai. Vs plain JS: baar-baar DOM mat chhedo.
Example
```

<template>
  <h1>{{ msg }}</h1>
</template>
<script>
export default { data() { return { msg: 'Hello' } } }
</script>
```
Project example: Navbar.vue + views (Login, Dashboard). data() / setup() reactive. fetch APIs.
Viva tipFayde: easy, SFC, reactivity. Vs React: chhota learning curve. Vs plain JS: UI state auto-update.
8

javascript frameworks

Times asked 1

Official solution

SimpleVue React Angular UI frameworks. Vue course choice.
What are JavaScript frameworks.
JS browser ki language. const rebind nahi, let block. Arrow () => this lexical.
Promise: pending/fulfill/reject. async/await usko seedha padhne jaisa. try/catch await pe. Yeh Celery nahi — Celery Python worker.
fetch native AJAX. array.filter/map computed lists. Vue data reactive; plain JS DOM querySelector se manual.
Project example: Vue.
Project example: Vue.
9

libraries used in app

Times asked 2

Official solution

SimpleStack bolo: Python, Flask, Jinja2, SQLAlchemy, SQLite, HTML/CSS/Bootstrap, maybe Chart.js.
10
server sent event

Times asked 3
Official solution

SimpleServer-Sent Events: server → browser one-way stream (text/event-stream). WebSocket full duplex hai; SSE simpler notifications ke liye.
Example
```
# client
const es = new EventSource('/stream');
es.onmessage = (e) => console.log(e.data);
```
11
smtp

Times asked 2
Official solution

SimpleSMTP = Simple Mail Transfer Protocol — email bhejne ka standard. Flask-Mail / smtplib se reminders/reports.
Example
```
from flask_mail import Message
msg = Message('Subject', recipients=[user.email])
msg.body = 'Hello'
mail.send(msg)
```
Viva tipViva mein MailHog/inbox dikhao. Port 587 TLS common; local pe MailHog 1025.
12
template inheritance

Times asked 4
Official solution

Simpleextends poora layout inherit karta hai, include chhota piece insert karta hai.
extends: child page base.html ka structure use karti hai, blocks override karti hai. Ek hi parent.
include: navbar.html / footer.html jahan chaho insert. Kai baar use ho sakta hai.
base.html:
```
{% block content %}{% endblock %}

home.html:
{% extends 'base.html' %}
{% block content %}<h1>Home</h1>{% endblock %}

{% include 'navbar.html' %}  → navbar har page pe
```
Fayda: header/footer ek jagah, change once — saari pages update. MAD1 mein almost har project use karta hai.
13
lifecycle hooks

Times asked 2
Official solution

SimpleLifecycle = component ki zindagi ke stages. API call tab jab DOM ready ho — mounted.
created: instance bani, this data, DOM nahi. mounted/onMounted: page pe aa gaya — fetch, Chart.js, setInterval.
updated: data change ke baad. unmounted: cleanup (clearInterval) warna memory leak.
Dashboards onMounted isliye: canvas/API tab valid. created mein $el nahi.
Composition: onMounted(() => {}) setup ke andar.
Example
```
export default {
  async mounted() {
    const r = await fetch('/api/venues')
    this.venues = await r.json()
  }
}
```
Project example: Venues.vue mounted fetch list. Clock component unmounted pe interval clear.
Viva tipcreated: data setup, DOM nahi. mounted/onMounted: $el mil gaya — fetch yahi. Dashboards isliye onMounted use karti hain.
14

csrf & cors

Times asked 2

Official solution

SimpleCSRF: attacker tumhari logged-in browser se unwanted POST. CSRF token form mein proof hai request genuine hai.
Viva tipFlask-WTF CSRF protect karta hai. Token bina POST reject.
15

mutations and actions

Times asked 2

Official solution

SimpleMutations sync diary entry. Actions async kaam phir diary.
Direct state mutate action se Vuex 4 discouraged. Devtools time-travel mutations.
Purpose of Actions: API, phir commit. Purpose of Mutations: state change one place.
Pehle 1-line definition, phir related MAD2 layer (Vue SFC / Flask route / models.py / tasks.py / Redis).
4-line formula: input kahan se aaya, auth/validation kaunsa, DB ya cache ya Celery, kya return.
Related mix mat karo — cache ≠ Celery, authentication ≠ authorization, v-if ≠ v-show, Beat ≠ Worker. Follow-up ke liye ek difference ready rakho.
Project example: action fetchVenues → commit setVenues. Mutation sirf array replace.
16

task queue and message queue

Times asked 2

Official solution

SimpleMessage queue generic. Task queue (Celery) specifically 'yeh function chalao'.
Redis list FIFO. Priority extra queues.
Pehle 1-line definition, phir related MAD2 layer (Vue SFC / Flask route / models.py / tasks.py / Redis).
4-line formula: input kahan se aaya, auth/validation kaunsa, DB ya cache ya Celery, kya return.
Related mix mat karo — cache ≠ Celery, authentication ≠ authorization, v-if ≠ v-show, Beat ≠ Worker. Follow-up ke liye ek difference ready rakho.
Project example: Celery is task queue on Redis broker.
17

what is dos -

Times asked 2

Official solution

SimpleDenial of Service flood/expensive queries se down. Rate limit, captcha, scale.
Course: validation, indexes, cache. Not full WAF.
Browser + API ke beech extra darwaze: CORS origin allow, HTTPS encrypt transit, CSRF cookie-auto-send attack, XSS HTML inject, SQL injection raw query.
MAD2 SPA: Vue :8080 Flask :5000 → Flask-CORS. JWT localStorage XSS se chori ho sakta — v-html user input pe avoid. Password Network tab localhost pe dikhega; prod HTTPS, response mein password echo nahi.
401 unauthenticated, 403 unauthorized, 400 validation. Hash one-way — SHA decrypt nahi hota. Secret key .env, GitHub pe nahi.
Project example: Don't allow unbounded export without auth.
18

opaque request

Times asked 2

Official solution

SimpleOpaque request/token: andar ka structure client ko meaningful nahi — bas string id. Server pe map hota hai. JWT transparent claims dikhata hai.
Viva tipSession id opaque hota hai; JWT payload base64 se padh sakte ho (sign alag).
19
Backend & Frontend validation

Times asked 2
Official solution

SimpleValidation = input rules: required, email format, length, unique. Frontend UX, backend security — dono.
Example
```
if not email or '@' not in email:
    flash('Invalid email')
    return redirect(request.url)
if User.query.filter_by(email=email).first():
    flash('Email taken')
```
20

plub/sub vs point to point

Times asked 3

Official solution

SimpleUngli rakhe to 4-line formula — panic ki jagah structure.
1) File ka role: model / Flask route / Vue SFC / celery task / config
2) Input kahan: JSON, params, token, props, $route
3) Kya kaam: query, cache, validation, .delay()
4) Output: jsonify, this.items, email, redirect
Unknown keyword: import, decorator, if, commit — har ka reason. Bluff mat.
Suggested flow1) Kaunsi layer?
2) Input?
3) DB/cache/task?
4) Response/UI?
Project example: Booking POST: jwt, seats check, commit, 201, Vue list push.
Viva tipUnknown keyword: import, decorator, if, commit — har ka reason. Panic mat.
21
explain models in details

Times asked 2
Official solution

Simplemodels.py = har table ki class: columns, PK/FK, relationships. Yeh Model layer hai.
Suggested flow1) Classes list karo
2) Har table ka kaam 1 line
3) Relationships (1-M / M-M)
4) Constraints (unique, nullable)
Example
```
class Lot(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(80), nullable=False)
    spots = db.relationship('Spot', backref='lot', lazy=True)
```
22
if you are trying to enter a string data to int field, what error will be thrown

Times asked 3
Official solution

SimpleInt column mein string daalne pe SQLAlchemy/DB type error ya Integrity/StatementError. Empty table pe bhi same validation fail — row count matter nahi.
Example
```
# SQLite may coerce sometimes; Postgres: invalid input syntax for integer
Spot(status='free', lot_id='abc')  # lot_id int → error
```
23
if you are trying to do a same in empty table will it throw error or not

Times asked 3
Official solution

SimpleInt column mein string daalne pe SQLAlchemy/DB type error ya Integrity/StatementError. Empty table pe bhi same validation fail — row count matter nahi.
Example
```
# SQLite may coerce sometimes; Postgres: invalid input syntax for integer
Spot(status='free', lot_id='abc')  # lot_id int → error
```
24
if throws, now what error

Times asked 3
Official solution

SimpleInt column mein string daalne pe SQLAlchemy/DB type error ya Integrity/StatementError. Empty table pe bhi same validation fail — row count matter nahi.
Example
```
# SQLite may coerce sometimes; Postgres: invalid input syntax for integer
Spot(status='free', lot_id='abc')  # lot_id int → error
```
25

Inline CSS vs external CSS

Times asked 2

Official solution

SimpleUngli rakhe to 4-line formula — panic ki jagah structure.
1) File ka role: model / Flask route / Vue SFC / celery task / config
2) Input kahan: JSON, params, token, props, $route
3) Kya kaam: query, cache, validation, .delay()
4) Output: jsonify, this.items, email, redirect
Unknown keyword: import, decorator, if, commit — har ka reason. Bluff mat.
Suggested flow1) Kaunsi layer?
2) Input?
3) DB/cache/task?
4) Response/UI?
Project example: Booking POST: jwt, seats check, commit, 201, Vue list push.
Viva tipUnknown keyword: import, decorator, if, commit — har ka reason. Panic mat.
26

Rate out of 10 and why?

Times asked 1

Official solution

SimpleApp rate 1–5 honestly + reason: completeness, UI, edge cases. Weak points improve plan ke saath bolo.

See reviews Level3_24 MAD1 Level 3

Aug 14, 2026

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1

Project Demonstration for first 7-8 mins.

Times asked 2

Official solution

SimpleDemo script pehle se practice: 5–7 min, Admin + User roles, saare mandatory features.
Suggested flow1) Register/login user
2) Admin login — CRUD
3) Approval/blacklist
4) Booking/apply + edge case
5) Search
6) Logout
Viva tipBolte-bolte dikhao. Code tab kholna jab poochhein.
2

Explain your database.

Times asked 1

Official solution

SimpleCode explain formula: input kya aaya → auth/validation → DB change → response/UI.
Viva tipFunction signature + 3-4 important lines + edge case.
3
Make any changes to your database.

Times asked 2
Official solution

SimpleLive UI change: relevant CSS/HTML template kholo — color, margin, flex, bootstrap class. Save + hard refresh.
Example
```
/* button red */
.btn-primary { background: red; }

/* center navbar item */
.navbar { justify-content: center; }
```
Viva tipDevTools se pehle try, phir file mein permanent change.
4

Rate your application out of 5. Reason for rating your application x.

Times asked 2

Official solution

Simple3.5–4/5 + why: core done, tests/UI missing. 5/5 overclaim.
Justify. Enjoy frontend vs backend honest.
Pehle 1-line definition, phir related MAD2 layer (Vue SFC / Flask route / models.py / tasks.py / Redis).
4-line formula: input kahan se aaya, auth/validation kaunsa, DB ya cache ya Celery, kya return.
Related mix mat karo — cache ≠ Celery, authentication ≠ authorization, v-if ≠ v-show, Beat ≠ Worker. Follow-up ke liye ek difference ready rakho.
Project example: Weak: celery demo flaky / UI.
Project example: Weak: celery demo flaky / UI.
5

Frontend and Back-end difference. Which is more important? 2-3 more questions that I cannot recall. But read the sheets properly for this proctor. All the questions were from there only. Also, don't get panicked seeing the above response about him as RUDE, he is cool. You'll enjoy answering questions. He might roast you sometimes (like why you don't know this, but that you'll enjoy).So no need to worry. Just prepare the questions from sheets. (This is the 8th Response for this proctor). Do check all the 7 previous responses and you are good to go!! Viva lasted for 35 mins. All the best 😇

Times asked 2

Official solution

SimpleViva wrap-up hai. Short thanks + confirm submission ZIP latest hai.

See reviews Level3_24 MAD1 Level 3

Aug 14, 2026

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1
ORM

Times asked 11
Official solution

SimpleORM = Object Relational Mapping. Database tables ko Python classes/objects se map karta hai, raw SQL kam likhni padti hai.
Bina ORM: cursor.execute('SELECT * FROM user WHERE id=?', [5])
ORM se: User.query.get(5) ya db.session.get(User, 5)
Example model
```
class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    email = db.Column(db.String(120), unique=True)
```
FaydePython mein soch sakte ho, SQL injection se protection (parameterized), relationships easy, DB switch thoda aasan.
Nuksaancomplex queries slow/abstract, seekhne ki layer extra, kabhi raw SQL phir bhi chahiye.
MAD1: SQLAlchemy (Flask-SQLAlchemy). Tables db.create_all() ya migrations se banti hain.
2

Packages used in project and why ?

Times asked 2

Official solution

SimpleStack bolo: Python, Flask, Jinja2, SQLAlchemy, SQLite, HTML/CSS/Bootstrap, maybe Chart.js.
3
Backend Front end validation

Times asked 2
Official solution

SimpleValidation = input rules: required, email format, length, unique. Frontend UX, backend security — dono.
Example
```
if not email or '@' not in email:
    flash('Invalid email')
    return redirect(request.url)
if User.query.filter_by(email=email).first():
    flash('Email taken')
```
4

Rate App out of 5 and why ?

Times asked 2

Official solution

SimpleApp rate 1–5 honestly + reason: completeness, UI, edge cases. Weak points improve plan ke saath bolo.
5

asked to do :

Times asked 2

Official solution

SimpleViva wrap-up hai. Short thanks + confirm submission ZIP latest hai.
6
change db column and change app accordingly

Times asked 2
Official solution

SimpleLive UI change: relevant CSS/HTML template kholo — color, margin, flex, bootstrap class. Save + hard refresh.
Example
```
/* button red */
.btn-primary { background: red; }

/* center navbar item */
.navbar { justify-content: center; }
```
Viva tipDevTools se pehle try, phir file mein permanent change.

See reviews Level2_94 MAD1 Level 2

Aug 14, 2026

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1

Verified ID Card, checksum then quietly observed the full demonstration

Times asked 2

Official solution

SimpleCamera pe clearly college/IITM ID dikhao — naam aur photo match hone chahiye.
Viva tipPehle se ID haath mein rakho, glare mat aane do. Iske baad GitHub + project run.
2
Asked me to change a heading from 'List of Songs' to just 'Songs'

Times asked 2
Official solution

SimpleLive UI change: relevant CSS/HTML template kholo — color, margin, flex, bootstrap class. Save + hard refresh.
Example
```
/* button red */
.btn-primary { background: red; }

/* center navbar item */
.navbar { justify-content: center; }
```
Viva tipDevTools se pehle try, phir file mein permanent change.
3
Different ways to declare a variable in Javascript

Times asked 2
Official solution

SimpleJS variables: var (function scope, old), let (block), const (block, reassign nahi).
Example
```
let count = 0;
const API = '/api';
```
4
Asked to show the models and state the relationship between the Songs, Albums, Playlists and Users tables (one-to-many, one-to-one relationships)

Times asked 2
Official solution

Simpledb.relationship se object graph: lot.spots, booking.user. backref reverse side auto deta hai.
Example
```
spots = db.relationship('Spot', backref='lot', cascade='all, delete-orphan')
```
5

That's it, took just 25 mins to finish L2 viva! Takeaway: A chill proctor, doesn't grill much about code. Check all above entries for this proctor and practise those questions, you'll be good to go.

Times asked 2

Official solution

SimpleViva wrap-up hai. Short thanks + confirm submission ZIP latest hai.

See reviews Level3_24 MAD1 Level 1

Aug 14, 2026

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Copy set link

1

Demo of the app

Times asked 8

Official solution

SimpleDemo script pehle se practice: 5–7 min, Admin + User roles, saare mandatory features.
Suggested flow1) Register/login user
2) Admin login — CRUD
3) Approval/blacklist
4) Booking/apply + edge case
5) Search
6) Logout
Viva tipBolte-bolte dikhao. Code tab kholna jab poochhein.
2

Explain Database

Times asked 1

Official solution

SimpleCode explain formula: input kya aaya → auth/validation → DB change → response/UI.
Viva tipFunction signature + 3-4 important lines + edge case.
3
ORM

Times asked 11
Official solution

SimpleORM = Object Relational Mapping. Database tables ko Python classes/objects se map karta hai, raw SQL kam likhni padti hai.
Bina ORM: cursor.execute('SELECT * FROM user WHERE id=?', [5])
ORM se: User.query.get(5) ya db.session.get(User, 5)
Example model
```
class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    email = db.Column(db.String(120), unique=True)
```
FaydePython mein soch sakte ho, SQL injection se protection (parameterized), relationships easy, DB switch thoda aasan.
Nuksaancomplex queries slow/abstract, seekhne ki layer extra, kabhi raw SQL phir bhi chahiye.
MAD1: SQLAlchemy (Flask-SQLAlchemy). Tables db.create_all() ya migrations se banti hain.
4
Backend & Frontend validation

Times asked 2
Official solution

SimpleValidation = input rules: required, email format, length, unique. Frontend UX, backend security — dono.
Example
```
if not email or '@' not in email:
    flash('Invalid email')
    return redirect(request.url)
if User.query.filter_by(email=email).first():
    flash('Email taken')
```
5

Point to point messaging

Times asked 1

Official solution

SimplePoint-to-point messaging: ek producer → ek queue → ek consumer. Celery task usually yahi. Pub/Sub = broadcast many subscribers.
6

Javascript framework used

Times asked 2

Official solution

SimpleStack bolo: Python, Flask, Jinja2, SQLAlchemy, SQLite, HTML/CSS/Bootstrap, maybe Chart.js.
7
Change background from white to red

Times asked 2
Official solution

SimpleLive UI change: relevant CSS/HTML template kholo — color, margin, flex, bootstrap class. Save + hard refresh.
Example
```
/* button red */
.btn-primary { background: red; }

/* center navbar item */
.navbar { justify-content: center; }
```
Viva tipDevTools se pehle try, phir file mein permanent change.
8

Rate your application out of 5 & why ?

Times asked 1

Official solution

Simple3.5–4/5 + why: core done, tests/UI missing. 5/5 overclaim.
Justify. Enjoy frontend vs backend honest.
Pehle 1-line definition, phir related MAD2 layer (Vue SFC / Flask route / models.py / tasks.py / Redis).
4-line formula: input kahan se aaya, auth/validation kaunsa, DB ya cache ya Celery, kya return.
Related mix mat karo — cache ≠ Celery, authentication ≠ authorization, v-if ≠ v-show, Beat ≠ Worker. Follow-up ke liye ek difference ready rakho.
Project example: Weak: celery demo flaky / UI.
Project example: Weak: celery demo flaky / UI.
9

All Questions asked were from the sheet only

Times asked 2

Official solution

SimpleViva wrap-up hai. Short thanks + confirm submission ZIP latest hai.

See reviews Level2_94 MAD1 Level 2

Aug 14, 2026

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1

horizontal & vertical scaling

Times asked 2

Official solution

SimpleVertical badi machine. Horizontal aur boxes + load balancer. JWT stateless horizontal friendly.
10k users: Postgres, Redis, gunicorn, CDN, pagination, indexes.
Millions: replicas, queue partition, more workers.
Pehle 1-line definition, phir related MAD2 layer (Vue SFC / Flask route / models.py / tasks.py / Redis).
4-line formula: input kahan se aaya, auth/validation kaunsa, DB ya cache ya Celery, kya return.
Related mix mat karo — cache ≠ Celery, authentication ≠ authorization, v-if ≠ v-show, Beat ≠ Worker. Follow-up ke liye ek difference ready rakho.
Project example: Course app vertical enough. Design answer scale-out.
2
template inheritance

Times asked 4
Official solution

Simpleextends poora layout inherit karta hai, include chhota piece insert karta hai.
extends: child page base.html ka structure use karti hai, blocks override karti hai. Ek hi parent.
include: navbar.html / footer.html jahan chaho insert. Kai baar use ho sakta hai.
base.html:
```
{% block content %}{% endblock %}

home.html:
{% extends 'base.html' %}
{% block content %}<h1>Home</h1>{% endblock %}

{% include 'navbar.html' %}  → navbar har page pe
```
Fayda: header/footer ek jagah, change once — saari pages update. MAD1 mein almost har project use karta hai.
3
if u add a string in a row which has int data-type will it throw error & vice versa

Times asked 2
Official solution

SimpleInt column mein string daalne pe SQLAlchemy/DB type error ya Integrity/StatementError. Empty table pe bhi same validation fail — row count matter nahi.
Example
```
# SQLite may coerce sometimes; Postgres: invalid input syntax for integer
Spot(status='free', lot_id='abc')  # lot_id int → error
```
4
if u query data from an empty table will it throw error

Times asked 2
Official solution

SimpleInt column mein string daalne pe SQLAlchemy/DB type error ya Integrity/StatementError. Empty table pe bhi same validation fail — row count matter nahi.
Example
```
# SQLite may coerce sometimes; Postgres: invalid input syntax for integer
Spot(status='free', lot_id='abc')  # lot_id int → error
```
5

what is JWT

Times asked 2

Official solution

SimpleJWT = JSON Web Token — signed string jisme user id/role hota hai. Har request header mein jaata hai. Session server pe store, JWT client pe.
Login → server token deta hai → Authorization: Bearer <token>
Payload: {sub: user_id, role: admin, exp: ...} — padha ja sakta hai, change nahi (signature).
Session: browser cookie, server-rendered Flask ke liye simple.
Token: mobile/Vue SPA, scaling (server memory nahi). Store: memory/httpOnly cookie, localStorage XSS risk.
MAD1 mostly session. Flask-Security session+login, JWT APIs ke liye.
6
what is lazy & backref

Times asked 2
Official solution

Simplebackref reverse attribute auto banata hai. back_populates dono sides explicitly naam dete ho — clearer.
Example
```
# backref
spots = db.relationship('Spot', backref='lot')
# spot.lot available

# back_populates
spots = db.relationship('Spot', back_populates='lot')
# Spot.lot = db.relationship('Lot', back_populates='spots')
```
7
difference between local storage & session storage

Times asked 2
Official solution

SimpleMAD1 mein usually session-based auth: login pe session['user_id'], har request pe verify.
Example
```
session['user_id'] = user.id
uid = session.get('user_id')
user = User.query.get(uid)
```
Viva tipSECRET_KEY set karo warna session insecure. logout pe session.clear().
8

overall the proctor was very calm & nice, didn't go much deep in the code, quietly watched the presentation didnt trouble much.

Times asked 2

Official solution

SimpleViva wrap-up hai. Short thanks + confirm submission ZIP latest hai.

See reviews Level3_24 MAD1 Level 3

Aug 14, 2026

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1

javascript frameworks used

Times asked 1

Official solution

SimpleVue React Angular UI frameworks. Vue course choice.
What are JavaScript frameworks.
JS browser ki language. const rebind nahi, let block. Arrow () => this lexical.
Promise: pending/fulfill/reject. async/await usko seedha padhne jaisa. try/catch await pe. Yeh Celery nahi — Celery Python worker.
fetch native AJAX. array.filter/map computed lists. Vue data reactive; plain JS DOM querySelector se manual.
Project example: Vue.
Project example: Vue.
2

what is point to point messaging

Times asked 1

Official solution

SimplePoint-to-point messaging: ek producer → ek queue → ek consumer. Celery task usually yahi. Pub/Sub = broadcast many subscribers.
3
frontend validation or backend validation - which is more important

Times asked 1
Official solution

SimpleValidation = input rules: required, email format, length, unique. Frontend UX, backend security — dono.
Example
```
if not email or '@' not in email:
    flash('Invalid email')
    return redirect(request.url)
if User.query.filter_by(email=email).first():
    flash('Email taken')
```

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