SQL with Backend Apps

Connecting Applications to Databases

Backend applications communicate with databases using Drivers or ORMs (Object-Relational Mappers).

ORM vs Raw SQL

• Raw SQL: Maximum control, manual mapping.
• ORM: Better dev experience, automatic mapping (e.g., Prisma, Sequelize, SQLAlchemy).

Node.js Example (using pg driver)

const { Pool } = require('pg');
const pool = new Pool({ connectionString: 'postgres://user:pass@localhost:5432/db' });

async function getUser(id) {
  const res = await pool.query('SELECT * FROM users WHERE id = $1', [id]);
  return res.rows[0];
}

Python Example (using sqlite3)

import sqlite3

con = sqlite3.connect("tutorial.db")
cur = con.cursor()

def get_movie(title):
    res = cur.execute("SELECT score FROM movie WHERE title = ?", (title,))
    return res.fetchone()