Why Query is the primary read operation in DynamoDB - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to query items from a DynamoDB table using the primary key.

DynamoDB

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

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

AFilterExpression

BScanIndexForward

CUserId

DProjectionExpression

Attempts:

3 left

💡 Hint

Common Mistakes

Using a non-key attribute in KeyConditionExpression causes errors.

Confusing FilterExpression with KeyConditionExpression.

The KeyConditionExpression requires the primary key attribute name. Here, 'UserId' is the partition key used to query items.

2fill in blank

medium

Complete the code to sort query results in descending order.

DynamoDB

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

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

AFilterExpression

BScanIndexForward

CConsistentRead

DProjectionExpression

Attempts:

3 left

💡 Hint

Common Mistakes

Using FilterExpression to sort results.

Omitting ScanIndexForward and expecting descending order.

The ScanIndexForward parameter controls the order of query results. Setting it to False returns results in descending order.

3fill in blank

hard

Fix the error in the query to use the correct key condition syntax.

DynamoDB

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

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

Aeq

Bbegins_with

Ccontains

Dfilter

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'filter' which is not a valid method here.

Using 'contains' or 'begins_with' incorrectly for partition key.

The eq method is used to specify equality in the key condition expression for querying by primary key.

4fill in blank

hard

Fill both blanks to query items with a partition key and sort key condition.

DynamoDB

response = table.query(KeyConditionExpression=Key('[1]').eq('123') & Key('[2]').[3]('2023-01-01'))

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

AUserId

BOrderDate

Cbegins_with

Deq

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'eq' for the sort key when a prefix match is needed.

Mixing up partition and sort key names.

The query uses the partition key 'UserId' with equality and the sort key 'OrderDate' with the begins_with function to filter items starting with a date prefix.

5fill in blank

hard

Fill all three blanks to create a query that filters results and projects specific attributes.

DynamoDB

response = table.query(KeyConditionExpression=Key('[1]').eq('123'), FilterExpression=Attr('[2]').[3]('active'), ProjectionExpression='UserId, [2]')

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

AUserId

BStatus

Ceq

Dbegins_with

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'begins_with' instead of 'eq' in FilterExpression.

Not including the filtered attribute in ProjectionExpression.

The query filters items where the 'Status' attribute equals 'active' and projects only 'UserId' and 'Status' attributes in the result.