By name: dynamodb description: AWS DynamoDB serverless NoSQL with streams and global tables. Use for AWS serverless.
Amazon DynamoDB
DynamoDB is a fully managed, serverless, key-value NoSQL database designed to run high-performance applications at any scale (Single-digit millisecond latency).
When to Use
- Serverless Apps: The default DB for AWS Lambda.
- Infinite Scaling: Handles petabytes of data without maintenance.
- Shopping Carts / Sessions: High throughput, simple key access.
Quick Start (AWS SDK v3)
import { DynamoDBClient, PutItemCommand } from "@aws-sdk/client-dynamodb";
const client = new DynamoDBClient({});
const command = new PutItemCommand({
TableName: "Users",
Item: {
PK: { S: "USER#123" },
SK: { S: "PROFILE" },
Name: { S: "Alice" },
},
});
await client.send(command);
Core Concepts
Partition Key (PK) & Sort Key (SK)
- PK: Determines which partition holds the data. Must be unique unless SK is present.
- SK: Sorts items with the same PK.
- Composite Key: PK + SK together form the primary ID.
Single Table Design (The "OneTable" Pattern)
Storing multiple entity types (Users, Orders) in one table to enable pre-joining data via item collections. (Less strictly required now, but still common).
Provisioned vs On-Demand
- On-Demand: Pay per request. Good for spiky/unknown loads.
- Provisioned: Pay for capacity. Cheaper for predictable loads.
Best Practices (2025)
Do:
- Access Patterns First: Design your schema based on how you will query the data. You cannot easily add arbitrary queries later.
- Use GSI (Global Secondary Index): To query by non-key attributes.
- Use TTL: To verify old items are deleted automatically (free delete).
Don't:
- Don't Scan: Scan reads the entire table. It is slow and expensive. Always
Query. - Don't store large blobs: 400KB limit per item. Store large data in S3 and save the link in Dynamo.