DP-900 Describe considerations for working with non-relational data on Azure Practice Test 9 — 15 Questions

Question 1

A mobile game developer needs to store player session data. Each session has a unique SessionID, a UserID, a start timestamp, an end timestamp, and a collection of game events (each event is a JSON object). The application requires low-latency point reads by SessionID and the ability to query all sessions for a given UserID within a time range. The schema of game events can vary between sessions (e.g., new event types added frequently). The developer wants a fully managed NoSQL database that supports flexible schemas and secondary indexing. Which Azure data store should they choose?

Accepted Answer

Azure Cosmos DB with the NoSQL API. Azure Cosmos DB with the NoSQL API is the correct choice because it provides a fully managed, globally distributed NoSQL database with native support for flexible schemas (schemaless JSON documents), low-latency point reads by partition key (SessionID), and automatic secondary indexing for querying by UserID within a time range. Its ability to handle varying game event schemas without schema migrations makes it ideal for this use case.

Answer

Azure Table Storage

Answer

Azure Blob Storage

Answer

Azure Cache for Redis

Question 2

A smart home company stores device telemetry in Azure Cosmos DB using the NoSQL API. Each document contains: deviceId (string), timestamp (datetime), temperature (float), humidity (float). The most common query retrieves all documents for a specific deviceId within a time range, ordered by timestamp descending. This query performs well. However, a new query that finds devices with temperature > 50 in the last hour (without specifying deviceId) is extremely slow and consumes many request units (RUs). What is the most likely cause?

Accepted Answer

The query does not specify the partition key (deviceId), causing a cross-partition query that scans every physical partition.. In Azure Cosmos DB NoSQL API, the partition key (deviceId) determines data distribution across physical partitions. Queries that do not include the partition key in the filter become cross-partition queries, which must fan out to every physical partition, scanning all documents. This is extremely slow and consumes many RUs, especially in large containers. The original query specifying deviceId performs well because it targets a single partition.

Answer

The temperature field is not indexed by default, so the query forces a full scan of all documents.

Answer

The time range filter on timestamp cannot be combined with the temperature filter efficiently.

Answer

The default indexing policy only indexes strings and numbers as range indexes, but temperature is stored as a number and is indexed.

Question 3

A social media analytics company needs to store large amounts of user activity logs. Each log entry contains a timestamp, user ID, activity type, and a dynamic set of custom attributes (e.g., page viewed, time spent). The application requires low-latency writes and point reads by a composite key (user ID and timestamp). The data is rarely updated after insertion. The company wants a fully managed NoSQL database that supports serverless throughput and automatic expiration of old logs (TTL). Which Azure Cosmos DB API should they choose?

Accepted Answer

Table API. The Table API is the correct choice because it provides a fully managed, serverless NoSQL database with automatic TTL (Time-to-Live) for data expiration, low-latency point reads and writes by a composite key (partition key + row key), and is optimized for storing large volumes of structured log data with dynamic attributes. It supports the exact requirements: high-throughput writes, point queries by user ID and timestamp, and automatic expiration of old logs without manual intervention.

Answer

NoSQL API (Core/SQL API)

Answer

Cassandra API

Answer

Gremlin API

Question 4

A retail company is designing a product catalog for its e-commerce website. Each product has a unique ProductID, a name, a price, and a variable number of attributes (e.g., size, color, weight) that differ across product categories. The application requires ability to read a product's details by ProductID with single-digit millisecond latency from any Azure region globally. The schema must be flexible to accommodate new attributes without schema changes. Which Azure data store should the company choose?

Accepted Answer

Azure Cosmos DB using the NoSQL API. Azure Cosmos DB with the NoSQL API is correct because it provides a fully managed, globally distributed NoSQL database that supports flexible schemas (allowing variable product attributes without schema changes) and guarantees single-digit millisecond read latency at any scale from any Azure region via its multi-region write and read replicas. The unique ProductID serves as a natural partition key, enabling efficient point reads with consistent low latency.

Answer

Azure Table Storage

Answer

Azure SQL Database

Answer

Azure Blob Storage

Question 5

Drag and drop the steps to configure a geo-replication for Azure Cosmos DB in the correct order.

Question 6

Drag and drop the steps to configure a firewall rule for Azure SQL Database in the correct order.

Question 7

Match each Azure storage redundancy option to its description.

Question 8

Match each Azure SQL Database tier to its description.

Question 9

A company stores sensor data in Azure Blob Storage. The data is appended every minute and rarely modified. The compliance team requires that blobs older than 90 days be moved to a more cost-effective storage tier, and blobs older than 365 days be deleted. Which solution should you recommend?

Accepted Answer

Configure a Blob Storage lifecycle management policy.. A lifecycle management policy can automatically transition blobs to cooler tiers (e.g., Cool after 90 days) and delete them after 365 days. Option B is wrong because Azure Files is for file shares. Option C is wrong because Blob Storage does not have a built-in backup retention policy for this scenario. Option D is wrong because Soft Delete is for recovery, not automated tiering or deletion.

Answer

Use Azure Backup to set a retention policy for the storage account.

Answer

Enable Blob Soft Delete and set retention days to 365.

Answer

Move the blobs to Azure Files and set a file retention policy.

Question 10

A global e-commerce company uses Azure Cosmos DB for its product catalog. The database is replicated across multiple regions. During a regional outage, customers in the affected region report that they cannot update product prices. The application team confirms that read requests succeed. What is the most likely cause of this issue?

Accepted Answer

The Cosmos DB account is configured with a single write region and automatic failover is not enabled.. In a multi-region write configuration, Cosmos DB can handle writes in any region. However, if the account is configured with a single write region, only that region can accept writes. During an outage of the write region, writes fail. Option A is wrong because read replicas are for read-only scenarios. Option B is wrong because consistency level does not affect write availability. Option D is wrong because failover is automatic if configured.

Answer

The application is using the wrong connection string for the region.

Answer

The consistency level is set to eventual, causing write conflicts.

Answer

The account is using read-only replicas in the affected region.

Question 11

You need to store JSON documents that are frequently read and written by a web application. Each document is about 10 KB. The solution must provide low-latency access globally. Which Azure data store should you use?

Accepted Answer

Azure Cosmos DB. Azure Cosmos DB is a globally distributed NoSQL database that supports JSON documents and provides low-latency access. Option A is wrong because Blob Storage is object storage, not optimized for individual document reads/writes. Option B is wrong because Table Storage is for key-value data. Option D is wrong because SQL Database is relational.

Answer

Azure Blob Storage

Answer

Azure SQL Database

Answer

Azure Table Storage

Question 12

A company stores terabytes of historical log data in Azure Blob Storage. The data is rarely accessed but must be retained for 10 years for compliance. The company wants to minimize storage costs. Which storage tier should you use?

Accepted Answer

Archive tier. The Archive tier is the correct choice because it is designed for data that is rarely accessed and has a flexible retrieval latency (hours), making it ideal for long-term retention of historical logs. It offers the lowest storage cost among Azure Blob Storage tiers, which directly minimizes costs for data that must be kept for 10 years but is seldom read.

Answer

Cool tier

Answer

Hot tier

Answer

Premium tier

Question 13

You need to upload a 500 GB file to Azure Blob Storage. The network connection is unreliable. Which feature should you use to ensure the upload completes successfully?

Accepted Answer

Use the Put Block and Put Block List operations with a block size that handles retries.. Option B is correct because the Put Block and Put Block List operations allow you to upload a large file as a series of individual blocks. Each block can be retried independently if the network fails, and the final Put Block List assembles the blocks into a single blob. This block-level retry mechanism ensures the upload completes despite an unreliable connection.

Answer

Configure a lifecycle management policy to tier the file.

Answer

Use Azure File Sync to synchronize the file to the cloud.

Answer

Use AzCopy with the /Z parameter to resume the upload.

Question 14

A company uses Azure Table Storage to store user session data. The data must be encrypted at rest. What should you do?

Accepted Answer

No action is required; Azure Storage encrypts data at rest by default.. Azure Table Storage, as part of Azure Storage, automatically encrypts all data at rest using Azure Storage Service Encryption (SSE) with 256-bit AES encryption. This encryption is enabled by default for all new and existing storage accounts, including Table Storage, and cannot be disabled. Therefore, no additional action is required to meet the encryption-at-rest requirement.

Answer

Enable Azure Storage Service Encryption (SSE).

Answer

Use Azure SQL Database Transparent Data Encryption (TDE).

Answer

Implement client-side encryption before storing data.

Question 15

You are designing a solution to store IoT device telemetry data. Each message is a small JSON payload (1-2 KB). The data is written once and read frequently for real-time dashboards. Which Azure data store should you use?

Accepted Answer

Azure Cosmos DB. Azure Cosmos DB is the correct choice because it is a globally distributed, multi-model database service that offers single-digit millisecond read and write latencies at any scale, making it ideal for real-time dashboards consuming IoT telemetry. Its support for JSON documents natively aligns with the small JSON payloads, and its ability to handle high-throughput writes (once) and low-latency reads (frequently) without schema management fits the workload perfectly.

Answer

Azure SQL Database

Answer

Azure Blob Storage

Answer

Azure Table Storage