Databases & System Design•Part 3: NoSQL & Document Databases (MongoDB, DynamoDB) (26 - 40)
TTL (Time-To-Live) Indexes:
In Simple Words: Automatically deletes documents after a specified duration. Ideal for sessions, caching, and OTP verification codes.
javascript
// Automatically delete session documents 1 hour (3600s) after createdAt:
db.sessions.createIndex(
{ "createdAt": 1 },
{ expireAfterSeconds: 3600 }
);