DynamoDB vs MySQL: Key Differences and When to Use Each

DynamoDB is a NoSQL, fully managed, key-value and document database designed for high scalability and low latency. MySQL is a relational SQL database best for structured data with complex queries and strong consistency requirements.

Quick Comparison

Here is a quick side-by-side comparison of DynamoDB and MySQL on key factors.

Factor	DynamoDB	MySQL
Data Model	NoSQL key-value and document	Relational tables with rows and columns
Scalability	Automatic horizontal scaling	Vertical scaling, manual sharding
Query Language	NoSQL API, limited query types	Standard SQL with joins and complex queries
Consistency	Eventual or strong consistency options	Strong consistency by default
Management	Fully managed by AWS	Self-managed or managed services
Use Case	High throughput, flexible schema	Complex transactions, structured data

Key Differences

DynamoDB uses a flexible NoSQL data model that stores data as key-value pairs or documents, allowing easy scaling and fast access without fixed schemas. It automatically handles scaling and replication across multiple servers, making it ideal for applications needing high availability and low latency.

In contrast, MySQL is a traditional relational database that organizes data into tables with fixed schemas and supports complex SQL queries including joins and transactions. It requires manual scaling and is often used when data integrity and complex relationships are critical.

While DynamoDB offers eventual consistency by default with an option for strong consistency, MySQL provides strong consistency and ACID transactions out of the box. This makes MySQL better for applications where precise data accuracy is essential.

Code Comparison

Here is how you insert and retrieve a simple item in DynamoDB using AWS SDK for JavaScript.

javascript

import { DynamoDBClient, PutItemCommand, GetItemCommand } from "@aws-sdk/client-dynamodb";

const client = new DynamoDBClient({ region: "us-east-1" });

async function run() {
  // Insert item
  await client.send(new PutItemCommand({
    TableName: "Users",
    Item: {
      "UserId": { S: "123" },
      "Name": { S: "Alice" }
    }
  }));

  // Get item
  const data = await client.send(new GetItemCommand({
    TableName: "Users",
    Key: { "UserId": { S: "123" } }
  }));

  console.log(data.Item);
}

run();

Output

{ UserId: { S: '123' }, Name: { S: 'Alice' } }

MySQL Equivalent

Here is how you insert and retrieve the same data in MySQL using SQL commands.

sql

CREATE TABLE Users (
  UserId VARCHAR(50) PRIMARY KEY,
  Name VARCHAR(100)
);

INSERT INTO Users (UserId, Name) VALUES ('123', 'Alice');

SELECT * FROM Users WHERE UserId = '123';

Output

+--------+-------+
| UserId | Name  |
+--------+-------+
| 123    | Alice |
+--------+-------+

When to Use Which

Choose DynamoDB when you need a highly scalable, fully managed NoSQL database with flexible schema and low latency for large-scale applications like gaming, IoT, or real-time analytics.

Choose MySQL when your application requires complex queries, strong ACID transactions, and structured relational data such as financial systems, content management, or traditional web apps.

Key Takeaways

DynamoDB is a NoSQL, fully managed database optimized for scalability and flexible data.

MySQL is a relational database with strong consistency and complex query support.

Use DynamoDB for high throughput and flexible schema needs.

Use MySQL for structured data and complex transactions.

DynamoDB scales automatically; MySQL requires manual scaling or sharding.