🌈 DynamoDB 

🧠 What is DynamoDB?

Amazon DynamoDB is a fully managed, serverless NoSQL database by AWS designed for high performance, extreme scalability, and low-latency workloads.

Think of DynamoDB as a super-fast digital filing cabinet that automatically grows, splits, balances, and manages itself — no servers, no storage ops, no maintenance.

🎨 KEY FEATURES

🌟 1. Fully Managed & Serverless

You NEVER manage:

• 🔧 servers

• 📈 capacity scaling

• 🛠️ upgrades

• 🔁 replication

AWS handles everything behind the scenes.

🚀 2. Extreme Performance

• ⚡ Millisecond response time

• ⚡ Built for real-time applications

• ⚡ Can handle millions of requests per second

Used by: Netflix, Snapchat, AirBnB, Amazon.

📦 3. NoSQL Data Model

DynamoDB is NOT relational.
It does not use SQL joins, foreign keys, or complex queries.

Instead, it uses:

• Tables

• Items (rows)

• Attributes (columns)

🏗️ DynamoDB Building Blocks 

🟨 Table

A collection of data — similar to a sheet in Excel.

🟩 Item

A single record (like a row).

🟦 Attributes

Data fields (like columns).

🔑 Keys in DynamoDB (VERY IMPORTANT)

🎯 1. Partition Key (PK)

A unique identifier for each item.
DynamoDB hashes the PK to decide the storage location.

Example:
UserID = 12345

🎯 2. Sort Key (SK)

Used with PK for composite key tables.
Allows multiple rows with same PK but different SK.

Example:

• PK: UserID = 12345

• SK: OrderID = 5678

Useful for:

• Ordering

• Filtering

• Storing hierarchical data

📚 Indexes in DynamoDB – So Data is Always Fast

🧭 1. Local Secondary Index (LSI)

• Same PK as the table

• Different sort key

• Up to 5 LSIs

Used for: Alternative sorting.

🌍 2. Global Secondary Index (GSI)

• Different PK & SK

• Acts like a new view of your data

• Very powerful

Used for: Flexible Querying.

⚙️ Capacity Modes 

🔥 1. On-Demand Mode

• You PAY only when you access data

• Good for unpredictable traffic

• Auto-scales instantly

Use when:
Traffic is spiky or unknown.

📏 2. Provisioned Mode

You define:

• Read Capacity Units (RCU)

• Write Capacity Units (WCU)

Use when:
You know your traffic patterns.

🧩 Data Access Patterns

DynamoDB supports:

• 🔍 Query → Fast, uses PK/SK

• 🔎 Scan → Slow, reads full table

• ✏️ PutItem

• 📖 GetItem

• 🧽 DeleteItem

• 🛠️ UpdateItem

🛡️ Security

🔒 Encryption at Rest

AWS KMS handles key management automatically.

🔐 IAM Authentication

Control who can read/write tables.

🌍 VPC Endpoints

Secure access inside private networks.

🌍 DynamoDB Global Tables (Multi-Region Magic)

Global tables replicate your data across multiple regions:

Benefits:

• 🌐 Low-latency worldwide

• 🔁 Automatic replication

• 💥 Disaster recovery built-in

• 🔄 Multi-master writes

Perfect for apps like:

• Messaging apps

• Multiplayer games

• E-commerce carts

🤖 DynamoDB Streams (Real-Time Triggers)

Streams capture every data change in real time.

Use cases:

• 🚨 Audit logs

• 🔄 Replication

• ⚡ Trigger AWS Lambda

• 📊 Analytics pipelines

🧮 DynamoDB Pricing

You pay for:

• 🟢 Reads

• 🔵 Writes

• 🟣 Storage

• 🟡 Streams

• 🔴 Backups

• 🟠 Global tables

No hidden charges.

🧠 WHEN TO USE DYNAMODB?

Perfect for:

• Real-time apps

• IoT

• Gaming

• E-commerce

• Chat apps

• Serverless backends

• High-volume API workloads

🚫 WHEN NOT TO USE DYNAMODB?

Avoid when you need:

• ❌ Complex SQL joins

• ❌ Multi-row transactions

• ❌ Long analytical queries

• ❌ Heavy ad-hoc querying

Use RDS or Redshift instead.

🎯 DynamoDB Example Table 

Table Name: Orders

🎉 FINAL SUMMARY

• 🚀 Fastest NoSQL DB on AWS

• 🔧 No server management

• 🌍 Multi-region & durable

• 🔥 Handles millions of requests/sec

• 🧭 Key-based design is crucial

• 🤖 Integrates with Lambda, S3, API Gateway