nosql-databases

name	nosql-databases
description	Master NoSQL databases: MongoDB, Redis, DynamoDB, and more.

NoSQL Databases

MongoDB

// Insert
db.users.insertOne({ name: 'John', age: 30 });

// Query
db.users.find({ age: { $gt: 25 } });

// Update
db.users.updateOne({ name: 'John' }, { $set: { age: 31 } });

// Aggregation
db.users.aggregate([
  { $match: { age: { $gt: 25 } } },
  { $group: { _id: null, avgAge: { $avg: '$age' } } }
]);

Redis

SET key value
GET key
DEL key
INCR counter
LPUSH list value
HSET hash field value

Database Comparison

• MongoDB: Document model, flexible schema
• Redis: In-memory, caching, pub/sub
• DynamoDB: Serverless, managed, pay-per-request
• Cassandra: Distributed, high throughput
• CouchDB: Document database, replication

Use Cases

• MongoDB: User profiles, content management
• Redis: Caching, sessions, leaderboards
• DynamoDB: High-traffic applications, real-time data

Best Practices

✅ Choose right database for use case ✅ Index frequently queried fields ✅ Plan for scaling ✅ Monitor performance ✅ Implement caching strategies ✅ Use appropriate data structures