DynamoDB Stream View Types: What They Are and How to Use Them

In DynamoDB, stream view types define what information about item changes is recorded in a stream. The four types are KEYS_ONLY, NEW_IMAGE, OLD_IMAGE, and NEW_AND_OLD_IMAGES, each capturing different parts of the changed data.

How It Works

DynamoDB streams capture changes made to items in a table, like a diary that records every update. The stream view type decides what details about these changes are saved in the stream.

Think of it like taking photos during an event: KEYS_ONLY is like snapping just the name tags of people who changed, NEW_IMAGE is a photo after the change, OLD_IMAGE is a photo before the change, and NEW_AND_OLD_IMAGES is like having both photos side by side.

This helps applications react to changes efficiently by choosing how much data they need from the stream.

Example

This example shows how to enable a DynamoDB stream with the NEW_AND_OLD_IMAGES view type using AWS CLI. This setting captures both the item before and after the change.

bash

aws dynamodb update-table \
  --table-name MusicCollection \
  --stream-specification StreamEnabled=true,StreamViewType=NEW_AND_OLD_IMAGES

Output

{
    "TableDescription": {
        "TableName": "MusicCollection",
        "StreamSpecification": {
            "StreamEnabled": true,
            "StreamViewType": "NEW_AND_OLD_IMAGES"
        },
        "LatestStreamArn": "arn:aws:dynamodb:region:account-id:table/MusicCollection/stream/timestamp"
    }
}

When to Use

Choose KEYS_ONLY when you only need to know which items changed, saving bandwidth and processing time.

Use NEW_IMAGE if you want to react to the latest state of an item, like updating a cache or search index.

OLD_IMAGE is useful for auditing or rollback scenarios where you need the previous data.

NEW_AND_OLD_IMAGES is best when you want to compare before and after states, such as syncing data or triggering complex workflows.

Key Points

• KEYS_ONLY: Only primary key attributes of changed items are recorded.
• NEW_IMAGE: The entire item after the change is recorded.
• OLD_IMAGE: The entire item before the change is recorded.
• NEW_AND_OLD_IMAGES: Both before and after images of the item are recorded.
• Choosing the right view type balances detail needed and resource use.

Key Takeaways

DynamoDB stream view types control what item data changes are captured in streams.

Use KEYS_ONLY to track changed items with minimal data.

NEW_IMAGE captures the updated item state after changes.

OLD_IMAGE captures the item state before changes for auditing.

NEW_AND_OLD_IMAGES provides full before-and-after data for detailed processing.