Why change tracking enables reactions in DynamoDB

Introduction

Change tracking helps us know when data changes. This lets us react quickly and keep things up to date.

When you want to update a dashboard as soon as data changes.

When you need to send notifications after a record is updated.

When syncing data between different systems automatically.

When logging changes for audit or history purposes.

When triggering workflows based on data updates.

Syntax

DynamoDB

Enable DynamoDB Streams on your table to track changes.
Use AWS Lambda to react to these stream events.

DynamoDB Streams capture item-level changes like inserts, updates, and deletes.

AWS Lambda functions can be triggered automatically by these stream events.

Examples

This setup tracks new and changed items and reacts by running your code.

DynamoDB

1. Enable DynamoDB Streams on your table with NEW_IMAGE option.
2. Create a Lambda function to process stream records.
3. Configure the Lambda trigger on the DynamoDB Stream.

This option lets you see both the old and new versions of changed items.

DynamoDB

StreamViewType: NEW_AND_OLD_IMAGES

Sample Program

This Lambda function logs every change detected by DynamoDB Streams.

DynamoDB

-- This is a conceptual example showing how to enable streams and react
-- Step 1: Enable stream on table (done in AWS Console or CLI)
-- Step 2: Lambda function code snippet (Node.js)
exports.handler = async (event) => {
  for (const record of event.Records) {
    console.log('Change detected:', record.eventName);
    console.log('New data:', JSON.stringify(record.dynamodb.NewImage));
  }
};

Important Notes

Change tracking is automatic once streams are enabled.

Reactions happen in near real-time, making your app responsive.

Remember to handle errors in your Lambda to avoid missing changes.

Summary

Change tracking tells you when data changes.

This lets you react quickly, like updating displays or sending alerts.

DynamoDB Streams and Lambda work together to enable this easily.