DynamoDB Streams and Triggers

DynamoDB Streams captures a time-ordered sequence of item-level changes in a table. Combined with AWS Lambda, Streams enables powerful event-driven architectures, real-time processing, and change data capture (CDC) patterns.

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What are DynamoDB Streams?

When you enable Streams on a table, DynamoDB records every item-level change:

• INSERT — a new item is added
• MODIFY — an existing item is updated
• REMOVE — an item is deleted

Application → DynamoDB Table → DynamoDB Stream → Consumer
                                    │
                                    ├── Lambda Function
                                    ├── Kinesis Data Streams
                                    └── Custom Application

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Stream View Types

When enabling Streams, you choose what data to include in the stream record:

View Type	Description	Use Case
KEYS_ONLY	Only the primary key attributes	When you just need to know which item changed
NEW_IMAGE	The entire item after the change	Processing the current state
OLD_IMAGE	The entire item before the change	Auditing what was changed
NEW_AND_OLD_IMAGES	Both before and after	Comparing changes, computing deltas

Enabling Streams (AWS CLI)