DP-900 Describe considerations for working with non-relational data on Azure Practice Test 7 — 15 Questions

Question 1

A media company stores video metadata in Azure Table Storage. Each video has a unique VideoID, and the application frequently queries for videos uploaded on a specific date. The current table uses PartitionKey = VideoID and RowKey = UploadDate. Queries filtering by UploadDate are slow and consume many transactions. Which design change will most optimize queries that retrieve all videos from a given date?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

C. Change the PartitionKey to a date-based value (e.g., YYYY-MM-DD) and use VideoID as the RowKey.. Azure Table Storage queries are most efficient when the PartitionKey is used as the primary filter. By changing the PartitionKey to a date-based value (e.g., YYYY-MM-DD), queries for all videos uploaded on a specific date become partition scans, which are fast and consume minimal transactions. Using VideoID as the RowKey still allows unique identification of each video within that date partition.

Answer

A. Use UploadDate as the RowKey only, but keep PartitionKey as VideoID.

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B. Create a secondary index on UploadDate.

Answer

D. Migrate the data to Azure Cosmos DB Table API for better indexing.

Question 2

A company stores user profile images in Azure Blob Storage. Each image is accessed via a URL that includes a Shared Access Signature (SAS) token generated using the storage account key. The company needs to immediately revoke access to all images for a specific user. Which action should they take?

Accepted Answer

Change the storage account access keys.. Changing the storage account access keys invalidates all SAS tokens that were generated using those keys, including any existing tokens. This immediately revokes access to all images for all users, including the specific user, without needing to manage individual tokens. SAS tokens are signed with the account key, so rotating the key renders all tokens generated with the old key invalid.

Answer

Delete the individual SAS tokens associated with that user's images.

Answer

Delete the container containing the user's images.

Answer

Regenerate the SAS token for each image.

Question 3

A development team is designing an application that stores user session data in Azure Cosmos DB. Each session document contains a sessionId (unique), userId, timestamp, and a JSON field 'metadata' that can include various optional properties. The application frequently queries by userId to retrieve all sessions for a particular user. Which property should be chosen as the partition key to optimize query performance and ensure even data distribution?

Accepted Answer

userId. The partition key should be the property most frequently used in queries and that provides high cardinality for even distribution. Since the application frequently queries by userId to retrieve all sessions for a user, choosing userId as the partition key ensures that all session documents for a given user are stored in the same logical partition, making these queries efficient and fast. Additionally, userId typically has a large number of distinct values, which promotes even data distribution across physical partitions.

Answer

sessionId

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timestamp

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metadata

Question 4

A startup is building a global user session store. Each session consists of a simple key (session ID) and a value (user data as a JSON string). The application requires low-latency reads and writes from any Azure region, and the data must be durable. Which Azure service is best suited for this scenario?

Accepted Answer

Azure Cosmos DB (Table API). Azure Cosmos DB (Table API) is the best fit because it provides global, multi-region writes with tunable consistency, guaranteed single-digit-millisecond latency for reads and writes at the 99th percentile, and full durability with automatic replication across any number of Azure regions. The Table API offers a key-value store interface (session ID as partition key, JSON value) while also supporting schema flexibility and SLA-backed performance, which is critical for a global user session store.

Answer

Azure Table Storage

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Azure Redis Cache

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Azure Blob Storage

Question 5

A social media company stores user posts in Azure Cosmos DB. Posts are frequently queried by user ID and creation timestamp. To minimize Request Units (RU) per query, which property should be chosen as the partition key?

Accepted Answer

User ID. User ID is the correct partition key because it evenly distributes writes and reads across physical partitions, ensuring that queries filtering by user ID and timestamp are scoped to a single partition. This minimizes cross-partition queries, which consume more Request Units (RU) than single-partition queries. Azure Cosmos DB routes each query to the partition containing the matching partition key value, so choosing User ID keeps most queries efficient.

Answer

Timestamp

Answer

Post content

Answer

A composite key of user ID and timestamp

Question 6

A smart home company stores sensor readings from thousands of devices in Azure Cosmos DB. Each reading includes a deviceID, timestamp (ISO format), sensor type, and value. The most common query retrieves all readings for a specific device within a time range. To minimize Request Units (RU) consumption and ensure even data distribution, which property should be chosen as the partition key?

Accepted Answer

A) deviceID. DeviceID is the correct partition key because it is the primary filter in the most common query (all readings for a specific device within a time range). Partitioning by deviceID ensures that all readings for a single device are stored in the same logical partition, making queries highly efficient by targeting a single partition. It also provides even data distribution across physical partitions, as thousands of devices will have roughly equal numbers of readings, minimizing RU consumption.

Answer

B) timestamp

Answer

C) sensor type

Answer

D) value

Question 7

A media company needs to store thousands of high-resolution videos. Each video is up to 10 GB in size and must be accessible via HTTP/HTTPS URLs for playback. The company does not require a file system hierarchy or SMB protocol support. Which Azure storage solution is most appropriate for this scenario?

Accepted Answer

Azure Blob Storage. Azure Blob Storage is designed for storing massive amounts of unstructured data, such as high-resolution videos, and provides HTTP/HTTPS access via URLs. It supports objects up to 4.77 TiB (or larger with premium block blobs), easily accommodating 10 GB files, and offers no file system hierarchy or SMB protocol, matching the company's requirements exactly.

Answer

Azure Files

Answer

Azure Queue Storage

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Azure Table Storage

Question 8

A mobile game stores player achievements in Azure Cosmos DB. Each player has a PlayerID, and achievements are stored as JSON documents with varying fields. The most common query retrieves all achievements for a specific player. To ensure low latency and efficient throughput, which property should be chosen as the partition key?

Accepted Answer

PlayerID. PlayerID is the correct partition key because the most common query retrieves all achievements for a specific player, and partitioning on PlayerID ensures that all documents for a given player are stored in the same physical partition. This allows the query to target a single partition, minimizing cross-partition queries and providing low latency and efficient throughput.

Answer

Timestamp

Answer

AchievementType

Answer

Region

Question 9

A logistics company stores sensor data from delivery trucks in Azure Table Storage. Each sensor reading includes a TruckID, Timestamp, Location, and EngineTemperature. The most common query retrieves all readings for all trucks within a specific one-hour time window (e.g., between 10:00 and 11:00 on a given day). Currently, the table uses PartitionKey = TruckID and RowKey = Timestamp (ISO format). However, queries filtering by time range are slow and consume many transactions. Which design change will most improve the performance of these time-range queries?

Accepted Answer

Change PartitionKey to a date-based value (e.g., YYYY-MM-DD) and RowKey to a composite of TruckID and Timestamp.. Azure Table Storage queries are most efficient when they target a specific PartitionKey and a range of RowKey values. By setting PartitionKey to a date-based value (e.g., YYYY-MM-DD), all readings for a given day are co-located in the same partition. Then, using a composite RowKey of TruckID and Timestamp allows the query to filter by time range within that partition using a single partition scan, drastically reducing the number of transactions and improving performance.

Answer

Change RowKey to be a composite of TruckID and Timestamp while keeping PartitionKey as TruckID.

Answer

Use Azure Cosmos DB with a partition key on Timestamp instead of Azure Table Storage.

Answer

Enable indexing on the Timestamp column in Azure Table Storage.

Question 10

A social media startup stores user profile data, posts, and comments in Azure Cosmos DB. They notice that the logical partition size for a popular user's profile is growing beyond 20 GB, causing performance issues. The current partition key is 'userId'. Which action should they take to solve this?

Accepted Answer

Change the partition key to a synthetic key combining userId and postId. A is correct because the logical partition size limit in Azure Cosmos DB is 20 GB. By using a synthetic partition key that combines 'userId' and 'postId', you distribute the data for the popular user across multiple logical partitions, preventing any single partition from exceeding the 20 GB limit and resolving the performance bottleneck.

Answer

Increase the RU/s

Answer

Split the container into multiple containers by userId range

Answer

Use a different API like MongoDB

Question 11

A ride-sharing application uses Azure Cosmos DB for trip data. Each trip record contains TripID (unique), DriverID, RiderID, TripDate, and other details. The most common query retrieves all trips for a specific driver within a given date range. Which partition key should be chosen to minimize Request Unit (RU) consumption and ensure even data distribution?

Accepted Answer

DriverID. DriverID is the optimal partition key because the most common query filters on DriverID and a date range. Partitioning by DriverID ensures that all trips for a specific driver are stored in the same physical partition, making the query a single-partition operation that consumes minimal Request Units (RUs). It also provides even data distribution across partitions because each driver generates a roughly similar number of trips, avoiding hot spots.

Answer

TripID

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TripDate

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RiderID

Question 12

A global e-commerce platform uses Azure Cosmos DB to store product inventory data. Customers add items to their cart, which reduces the available inventory count. The application requires that after a customer adds an item, any subsequent read of that product's inventory from any region in the world must reflect the reduced count immediately. Which Cosmos DB consistency level should be used?

Accepted Answer

Strong consistency. Strong consistency ensures that any read operation returns the most recent write, regardless of the region. Since the application requires that after a customer adds an item, any subsequent read of that product's inventory from any region must reflect the reduced count immediately, Strong consistency is the only level that guarantees linearizability and zero staleness across all replicas.

Answer

Eventual consistency

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Consistent prefix consistency

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Session consistency

Question 13

A hospital stores patient vital signs data in Azure Cosmos DB. Each document contains PatientID, Timestamp, HeartRate, BloodPressure, and other measurements. The most common query retrieves all vital signs for a specific patient within a time range (e.g., last 24 hours). Which property should be chosen as the partition key to minimize Request Unit (RU) consumption and ensure even data distribution?

Accepted Answer

PatientID. PatientID is the ideal partition key because the most common query filters by PatientID and a time range. With PatientID as the partition key, Cosmos DB can route the query to a single physical partition containing all documents for that patient, minimizing cross-partition queries and reducing RU consumption. It also ensures even data distribution since each patient generates a similar volume of vital signs data, avoiding hot partitions.

Answer

Timestamp

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HeartRate

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BloodPressure

Question 14

A company stores terabytes of customer support chat transcripts in JSON format. The data is rarely modified and needs to be accessed by analysts using SQL queries. The analysts do not want to manage servers or provision throughput. Which Azure service should be used to store and query this data?

Accepted Answer

Azure Blob Storage (with Azure Data Lake Storage Gen2) and query using Azure Synapse Serverless SQL. Azure Blob Storage with Azure Data Lake Storage Gen2 provides a cost-effective, scalable solution for storing large volumes of JSON data in its native format. By using Azure Synapse Serverless SQL, analysts can query this data directly with standard T-SQL without provisioning any infrastructure or managing throughput, meeting the requirement for serverless, on-demand querying of rarely modified data.

Answer

Azure Cosmos DB

Answer

Azure Table Storage

Answer

Azure SQL Database

Question 15

A company stores backup files in Azure Blob Storage. The backup files are accessed frequently for the first 30 days, then only rarely for the next six months. After one year, the files must be retained for compliance but are never accessed. The company wants to minimize storage costs. Which solution should they use?

Accepted Answer

Use Azure Blob Storage lifecycle management policies. Azure Blob Storage lifecycle management policies allow you to automatically transition blobs to cooler tiers (e.g., from Hot to Cool after 30 days, then to Archive after one year) and delete blobs after a specified period, all without manual intervention. This directly matches the access pattern: frequent access for 30 days, rare access for six months, and never accessed after one year, minimizing storage costs by using the most cost-effective tier for each phase.

Answer

Manually move files between storage accounts

Answer

Use Azure File Sync

Answer

Use Azure NetApp Files