DynamoDB Streams overview in AWS - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to enable DynamoDB Streams on a table.

AWS

aws dynamodb update-table --table-name MyTable --stream-specification StreamEnabled=[1]

Drag options to blanks, or click blank then click option'

Afalse

Btrue

CEnabled

DYes

Attempts:

3 left

💡 Hint

Common Mistakes

Using string values like 'Enabled' instead of boolean true.

To enable DynamoDB Streams, the StreamEnabled parameter must be set to true.

2fill in blank

medium

Complete the code to specify the stream view type when enabling DynamoDB Streams.

AWS

aws dynamodb update-table --table-name MyTable --stream-specification StreamViewType=[1]

Drag options to blanks, or click blank then click option'

AKEYS_ONLY

BFULL_IMAGE

CNEW_IMAGE

DOLD_IMAGE

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing FULL_IMAGE which captures all attributes, not just keys.

The StreamViewType defines what information the stream captures. KEYS_ONLY captures only the primary key attributes.

3fill in blank

hard

Fix the error in the AWS CLI command to describe the latest stream ARN for a DynamoDB table.

AWS

aws dynamodb describe-table --table-name [1]

Drag options to blanks, or click blank then click option'

ATableName

BMyStream

CMyTable

DStreamARN

Attempts:

3 left

💡 Hint

Common Mistakes

Using the stream ARN instead of the table name.

The describe-table command requires the table name, not the stream name or ARN.

4fill in blank

hard

Fill both blanks to create a Python snippet that reads records from a DynamoDB stream using boto3.

AWS

response = client.get_records(ShardIterator=[1], Limit=[2])

Drag options to blanks, or click blank then click option'

A'shard_iterator_value'

B100

C200

D'iterator_value'

Attempts:

3 left

💡 Hint

Common Mistakes

Using an integer for ShardIterator or a string for Limit.

The ShardIterator must be a string token, and Limit is an integer specifying max records.

5fill in blank

hard

Fill all three blanks to configure a DynamoDB stream with NEW_IMAGE view and enable it using AWS CLI.

AWS

aws dynamodb update-table --table-name [1] --stream-specification StreamEnabled=[2],StreamViewType=[3]

Drag options to blanks, or click blank then click option'

AMyTable

Btrue

CNEW_IMAGE

Dfalse

Attempts:

3 left

💡 Hint

Common Mistakes

Disabling the stream or using incorrect view types.

To enable streams with NEW_IMAGE view, set StreamEnabled to true and StreamViewType to NEW_IMAGE for the correct table.

Practice

1. What is the main purpose of DynamoDB Streams?

easy

A. To store backups of DynamoDB tables permanently

B. To encrypt data stored in DynamoDB tables

C. To increase the read capacity of a DynamoDB table

D. To track and react to data changes in real time

Solution

1. Step 1: Understand DynamoDB Streams function

   DynamoDB Streams capture data changes like inserts, updates, and deletes in real time.

2. Step 2: Compare options with Streams purpose

   Only To track and react to data changes in real time correctly describes tracking and reacting to data changes. Other options describe unrelated features.

3. Final Answer:

   To track and react to data changes in real time -> Option D

4. Quick Check:

   DynamoDB Streams = Track data changes [OK]

Hint: Streams capture table changes instantly for reaction [OK]

Common Mistakes:

• Confusing Streams with backup or encryption features
• Thinking Streams increase read capacity
• Assuming Streams store data permanently

2. Which setting must be enabled to start using DynamoDB Streams on a table?

easy

A. EncryptionEnabled set to true

B. BackupEnabled set to true

C. StreamEnabled set to true

D. AutoScalingEnabled set to true

Solution

1. Step 1: Identify the configuration for enabling Streams

   To use DynamoDB Streams, the table must have StreamEnabled set to true.

2. Step 2: Eliminate unrelated settings

   BackupEnabled, EncryptionEnabled, and AutoScalingEnabled do not enable Streams.

3. Final Answer:

   StreamEnabled set to true -> Option C

4. Quick Check:

   Enable Streams = StreamEnabled true [OK]

Hint: Enable Streams by setting StreamEnabled true [OK]

Common Mistakes:

• Confusing Streams with backups or encryption
• Assuming AutoScaling enables Streams
• Forgetting to enable Streams explicitly

3. Given a DynamoDB Stream with StreamViewType set to NEW_AND_OLD_IMAGES, what data will the stream record for each change?

medium

A. Only the new item image after the change

B. Both the new and old item images

C. Only the keys of the changed items

D. Only the old item image before the change

Solution

1. Step 1: Understand StreamViewType NEW_AND_OLD_IMAGES meaning

   This setting records both the item before and after the change.

2. Step 2: Compare options with StreamViewType behavior

   Only Both the new and old item images matches the behavior of capturing both new and old images.

3. Final Answer:

   Both the new and old item images -> Option B

4. Quick Check:

   NEW_AND_OLD_IMAGES = new + old data [OK]

Hint: NEW_AND_OLD_IMAGES means capture before and after data [OK]

Common Mistakes:

• Choosing only new or only old images
• Confusing keys only with full images
• Not knowing StreamViewType options

4. A developer enabled DynamoDB Streams but does not see any stream records after table updates. What is the most likely cause?

medium

A. StreamEnabled is false on the table

B. StreamViewType is set to KEYS_ONLY

C. Stream retention period is set to 7 days

D. The table has no primary key defined

Solution

1. Step 1: Check if Streams are enabled

   If StreamEnabled is false, no stream records are generated regardless of updates.

2. Step 2: Evaluate other options

   KEYS_ONLY still produces records; retention period (24-168 hours) does not prevent seeing recent records; tables require primary keys but that doesn't stop streams if enabled.

3. Final Answer:

   StreamEnabled is false on the table -> Option A

4. Quick Check:

   No records = Streams not enabled [OK]

Hint: Streams must be enabled to see records [OK]

Common Mistakes:

• Assuming KEYS_ONLY disables records
• Thinking retention period prevents seeing records
• Ignoring StreamEnabled setting

5. You want to trigger a Lambda function whenever an item is updated in your DynamoDB table to process both the old and new item images. Which DynamoDB Streams configuration and setup is required?

hard

A. Enable Streams with StreamViewType NEW_AND_OLD_IMAGES and configure Lambda trigger on the stream

B. Enable Streams with StreamViewType KEYS_ONLY and configure Lambda trigger on the table

C. Enable Streams with StreamViewType NEW_IMAGE and configure Lambda trigger on the stream

D. Enable Streams with StreamViewType OLD_IMAGE and configure Lambda trigger on the table

Solution

1. Step 1: Choose StreamViewType for updates

   To capture both before and after update data, use NEW_AND_OLD_IMAGES.

2. Step 2: Configure Lambda trigger on the DynamoDB Stream

   Lambda triggers must be set on the stream, not directly on the table.

3. Final Answer:

   Enable Streams with StreamViewType NEW_AND_OLD_IMAGES and configure Lambda trigger on the stream -> Option A

4. Quick Check:

   Lambda trigger on stream with NEW_AND_OLD_IMAGES [OK]

Hint: Use NEW_AND_OLD_IMAGES and trigger Lambda on stream [OK]

Common Mistakes:

• Triggering Lambda directly on table instead of stream
• Choosing KEYS_ONLY or OLD_IMAGE for update data
• Not enabling Streams before Lambda trigger