MongoDB vs PHP Which Should Beginners Learn First?

<?php
// hello.php - run with: php -S localhost:8000
$name = $_GET['name'] ?? 'learner';
$safe = htmlspecialchars($name, ENT_QUOTES, 'UTF-8');
?>
<!DOCTYPE html>
<html>
  <body>
    <h1>Hello, <?= $safe ?>!</h1>
    <p>Today is <?= date('d M Y') ?>.</p>
  </body>
</html>

// mongosh
use school
db.students.insertMany([
  { name: "Aman", class: 10, marks: 82 },
  { name: "Riya", class: 10, marks: 91 }
])
db.students.find({ marks: { $gt: 85 } })

<?php
$pdo = new PDO('mysql:host=localhost;dbname=shop;charset=utf8mb4', 'app', 'secret', [
    PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
]);

$stmt = $pdo->prepare('INSERT INTO products (name, price) VALUES (:name, :price)');
$stmt->execute([':name' => 'Notebook', ':price' => 45.0]);

$rows = $pdo->query('SELECT id, name, price FROM products ORDER BY id DESC')->fetchAll(PDO::FETCH_ASSOC);
foreach ($rows as $r) {
    echo $r['id'] . ' - ' . htmlspecialchars($r['name']) . ' - ' . $r['price'] . PHP_EOL;
}

CREATE TABLE products (
  id    INT AUTO_INCREMENT PRIMARY KEY,
  name  VARCHAR(100) NOT NULL,
  price DECIMAL(10,2) NOT NULL CHECK (price >= 0)
);

<?php
// Requires the mongodb PHP extension and: composer require mongodb/mongodb
require 'vendor/autoload.php';

$client = new MongoDB\Client('mongodb://localhost:27017');
$students = $client->school->students;

$students->insertOne(['name' => 'Kabir', 'class' => 10, 'marks' => 77]);
foreach ($students->find(['marks' => ['$gte' => 80]]) as $s) {
    echo $s['name'] . ': ' . $s['marks'] . PHP_EOL;
}

MongoDB is a good fit when:
- records have varying fields (e.g. product attributes)
- you read whole documents at once
- your stack is Node.js or Python
MySQL is a good fit when:
- data is highly relational (orders, payments, users)
- you need strict schemas and joins
- you work with typical PHP hosting

Project: Student marks manager
Features:
- Add a student (name, class, marks)
- List students, highest marks first
- Edit marks
- Delete a student
Version 1: PHP + MySQL (PDO)
Version 2: PHP + MongoDB (mongodb/mongodb)
Compare: code length, query style, schema changes

marks-app/
├── public/
│   ├── index.php     # list
│   ├── add.php       # form + insert
│   └── edit.php      # form + update
├── src/
│   └── db.php        # connection (reads env vars)
├── .env.example
└── README.md

Step 1: HTML + CSS basics
Step 2: PHP syntax, forms, arrays, functions
Step 3: SQL with MySQL - CRUD, joins
Step 4: PHP + PDO CRUD app (version 1)
Step 5: MongoDB basics in mongosh
Step 6: Version 2 with MongoDB
Step 7: Laravel, if you target PHP jobs