Why single-table design matters in DynamoDB - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to specify the primary key attribute name in a DynamoDB table creation.

DynamoDB

KeySchema: [{ AttributeName: [1], KeyType: 'HASH' }]

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

AUsername

BUserId

CEmail

DTimestamp

Attempts:

3 left

💡 Hint

Common Mistakes

Using a non-unique attribute as the primary key.

Confusing sort key with partition key.

The primary key attribute name must be specified correctly to uniquely identify items. 'UserId' is a common choice for a partition key.

2fill in blank

medium

Complete the code to add a sort key attribute in the DynamoDB table schema.

DynamoDB

KeySchema: [ { AttributeName: 'UserId', KeyType: 'HASH' }, { AttributeName: [1], KeyType: 'RANGE' } ]

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

AStatus

BEmail

CUsername

DTimestamp

Attempts:

3 left

💡 Hint

Common Mistakes

Using an attribute that does not help sort items logically.

Omitting the sort key when multiple items per partition exist.

The sort key allows sorting and querying items with the same partition key. 'Timestamp' is commonly used to order events or records.

3fill in blank

hard

Fix the error in the query to fetch all items for a user using the partition key.

DynamoDB

const params = { TableName: 'Users', KeyConditionExpression: 'UserId = [1]', ExpressionAttributeValues: { ':uid': userId } };

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

A:uid

BuserId

CUserId

D?uid

Attempts:

3 left

💡 Hint

Common Mistakes

Using the attribute name directly instead of a placeholder.

Using a question mark instead of a colon for placeholders.

In DynamoDB queries, placeholders for values start with a colon ':' and must match keys in ExpressionAttributeValues.

4fill in blank

hard

Fill both blanks to create a DynamoDB update expression that sets a new attribute and increments a counter.

DynamoDB

UpdateExpression: 'SET [1] = :newVal, [2] = [2] + :inc'

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

ALastLogin

BLoginCount

CUserName

DStatus

Attempts:

3 left

💡 Hint

Common Mistakes

Using different attribute names for incrementing.

Forgetting to use the attribute name consistently.

The 'SET' clause updates 'LastLogin' to a new value and increments 'LoginCount' by a given amount.

5fill in blank

hard

Fill all three blanks to create a DynamoDB query that filters items by status and sorts by timestamp.

DynamoDB

const params = { TableName: 'Orders', KeyConditionExpression: '[1] = :userId', FilterExpression: '[2] = :status', ScanIndexForward: [3] };

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

AUserId

BOrderStatus

Ctrue

Dfalse

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong attribute names in expressions.

Confusing true and false for ScanIndexForward.

The query uses 'UserId' as the partition key, filters by 'OrderStatus', and sorts results in descending order (ScanIndexForward: false).