PostgreSQL vs MongoDB Comparison

-- PostgreSQL - user and order query
CREATE TABLE users (
  id SERIAL PRIMARY KEY,
  email TEXT UNIQUE NOT NULL,
  profile JSONB,
  created_at TIMESTAMPTZ DEFAULT NOW()
);

CREATE TABLE orders (
  id SERIAL PRIMARY KEY,
  user_id INT REFERENCES users(id),
  total NUMERIC(10,2) NOT NULL,
  status TEXT CHECK (status IN ('pending','paid','shipped'))
);

-- Per-user total with window function
SELECT u.email,
       SUM(o.total) AS toplam_harcama,
       RANK() OVER (ORDER BY SUM(o.total) DESC) AS siralama
FROM users u
JOIN orders o ON o.user_id = u.id
GROUP BY u.email;

// MongoDB - user and order operations (Node.js)
import { MongoClient } from 'mongodb';

const client = new MongoClient(process.env.MONGO_URI!);
const db = client.db('shop');

// Flexible document structure — no schema migration
await db.collection('users').insertOne({
  email: '[email protected]',
  profile: { bio: 'Developer', social: { github: 'ali' } },
  createdAt: new Date()
});

// Order totals with aggregation pipeline
const result = await db.collection('orders').aggregate([
  { $match: { status: 'paid' } },
  { $group: { _id: '$userId', toplamHarcama: { $sum: '$total' } } },
  { $sort: { toplamHarcama: -1 } },
  { $limit: 10 }
]).toArray();