Scan vs Query performance comparison in DynamoDB - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to perform a Query operation on a DynamoDB table.

DynamoDB

response = table.[1](KeyConditionExpression=Key('UserId').eq('123'))

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

Aget_item

Bscan

Cquery

Dput_item

Attempts:

3 left

💡 Hint

Common Mistakes

Using scan instead of query for key-based retrieval.

The query method retrieves items based on primary key values, making it efficient.

2fill in blank

medium

Complete the code to perform a Scan operation on a DynamoDB table.

DynamoDB

response = table.[1]()

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

Aquery

Bscan

Cget_item

Ddelete_item

Attempts:

3 left

💡 Hint

Common Mistakes

Using query when wanting to read all items.

The scan method reads every item in the table, which can be slow for large tables.

3fill in blank

hard

Fix the error in the code to improve performance by using the correct method.

DynamoDB

response = table.[1](KeyConditionExpression=Key('Status').eq('Active'))

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

Aquery

Bput_item

Cget_item

Dscan

Attempts:

3 left

💡 Hint

Common Mistakes

Using scan with filter instead of query with key condition.

Using query with a key condition is more efficient than scanning with a filter.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that shows item counts for active users using Query.

DynamoDB

active_users = {item['UserId']: item['Count'] for item in table.[1](KeyConditionExpression=Key('Status').eq('Active')).[2]

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

Aquery

Bscan

CItems

Dresponse

Attempts:

3 left

💡 Hint

Common Mistakes

Using scan instead of query, or accessing wrong attribute for items.

Use query to get items with key condition, then access Items to iterate results.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that filters items with Query and a condition.

DynamoDB

filtered = {item['Id']: item['Value'] for item in table.[1](KeyConditionExpression=Key('Category').eq('Books')).[2] if item['Value'] [3] 100}

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

Aquery

BItems

C>

Dscan

Attempts:

3 left

💡 Hint

Common Mistakes

Using scan instead of query, or wrong comparison operator.

Use query to filter by key, access Items to get results, and filter values greater than 100.