Database Access in Node.js: Connecting Relational and NoSQL Databases

Learn how to access both relational and NoSQL databases in Node.js. This guide covers best practices, examples for MySQL, PostgreSQL, and MongoDB, and provides a comprehensive list of drivers and NPM commands for various databases.

Database Access

Node.js supports both relational and NoSQL databases, requiring specific drivers for each. Here’s a guide to popular databases and their drivers:

Best Practices and Considerations

• Connection Pooling: Use connection pooling to improve performance.
• Error Handling: Implement robust error handling to avoid failures.
• Asynchronous Operations: Handle async operations with promises or async/await.
• Security: Use parameterized queries, validate input, and manage passwords securely.
• ORMs and ODMs: Utilize ORMs like Sequelize and ODMs like Mongoose for easier database interactions.
• Performance Optimization: Optimize queries, use indexing, and consider caching.

MySQL:

const mysql = require('mysql');
const connection = mysql.createConnection({
  host: 'localhost',
  user: 'root',
  password: 'password',
  database: 'test'
});

connection.connect(err => {
  if (err) throw err;
  console.log('Connected to MySQL!');
});

connection.query('SELECT * FROM users', (err, results) => {
  if (err) throw err;
  console.log(results);
});

connection.end();
        

Connected to MySQL!
[ { id: 1, name: 'Alice' }, { id: 2, name: 'Bob' } ]
        

PostgreSQL:

const { Client } = require('pg');
const client = new Client({
  host: 'localhost',
  user: 'postgres',
  password: 'password',
  database: 'test'
});

client.connect()
  .then(() => console.log('Connected to PostgreSQL!'))
  .catch(err => console.error('Connection error', err.stack));

client.query('SELECT * FROM users', (err, res) => {
  if (err) throw err;
  console.log(res.rows);
  client.end();
});
        

Connected to PostgreSQL!
[ { id: 1, name: 'Alice' }, { id: 2, name: 'Bob' } ]
        

NoSQL Databases

MongoDB:

const { MongoClient } = require('mongodb');
const url = 'mongodb://localhost:27017';
const client = new MongoClient(url);

client.connect()
  .then(() => {
    console.log('Connected to MongoDB!');
    const db = client.db('test');
    return db.collection('users').find({}).toArray();
  })
  .then(users => {
    console.log(users);
    client.close();
  })
  .catch(err => console.error('Connection error', err));
        

Connected to MongoDB!
[ { _id: ObjectId('...'), name: 'Alice' }, { _id: ObjectId('...'), name: 'Bob' } ]
        

Code Examples

Here are examples for connecting to different databases and performing CRUD operations:

Relational Databases

NoSQL Databases

Note: The list of databases and drivers is extensive. Choose drivers based on your specific needs.