Why access patterns drive design 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 query.

DynamoDB

KeyConditionExpression = '#pk = :[1]'

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

Apartition_key

BuserId

Cpk_value

DpartitionKey

Attempts:

3 left

💡 Hint

Common Mistakes

Using an attribute name that does not exist in the table schema.

Confusing partition key with sort key names.

The primary key attribute name used in the query must match the table's partition key, commonly named 'userId' in examples.

2fill in blank

medium

Complete the code to specify the index name for a DynamoDB query to support a specific access pattern.

DynamoDB

IndexName='[1]'

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

AGSI1

BPrimaryIndex

CLocalIndex

DSecondaryIndex

Attempts:

3 left

💡 Hint

Common Mistakes

Using the primary index name instead of the GSI name.

Using incorrect index names that do not exist.

Global Secondary Indexes (GSIs) are named like 'GSI1' to support alternate access patterns.

3fill in blank

hard

Fix the error in the DynamoDB query expression to correctly filter items by sort key.

DynamoDB

KeyConditionExpression = '#pk = :userId AND [1] = :sortKeyVal'

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

Ask

Bsort_key

CsortKeyVal

DsortKey

Attempts:

3 left

💡 Hint

Common Mistakes

Using the full name 'sortKey' instead of the attribute name.

Using the value variable name instead of the attribute name.

The sort key attribute is often abbreviated as 'sk' in DynamoDB table designs to support access patterns.

4fill in blank

hard

Fill both blanks to create a DynamoDB query that uses a partition key and a begins_with condition on the sort key.

DynamoDB

KeyConditionExpression = '#pk = :userId AND begins_with(#[1], :[2])'

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

Ask

BsortKey

Cprefix

DskPrefix

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect attribute names for the sort key.

Confusing the prefix variable name with the attribute name.

The sort key attribute is 'sk', and the begins_with function uses a prefix string to filter items starting with that prefix.

5fill in blank

hard

Fill all three blanks to build a DynamoDB query that filters items by partition key, sort key greater than a value, and uses a specific index.

DynamoDB

response = table.query(IndexName='[1]', KeyConditionExpression='#pk = :userId AND #sk [2] :sortVal', ExpressionAttributeNames={'#pk': 'userId', '#sk': '[3]'}, ExpressionAttributeValues={':userId': '123', ':sortVal': '2023-01-01'})

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

AGSI2

B>

CcreatedAt

DPrimaryIndex

Attempts:

3 left

💡 Hint

Common Mistakes

Using the primary index name instead of the GSI.

Using '=' instead of '>' for the sort key condition.

Mismatching attribute names in ExpressionAttributeNames.

The query uses the global secondary index 'GSI2', the greater than operator '>' for filtering sort keys, and the sort key attribute 'createdAt'.