DP-900 Describe considerations for working with non-relational data on Azure Practice Test 5 — 15 Questions

Question 1

A company stores user profiles as JSON documents. Each profile includes standard fields (userId, name, email) and optional fields (preferences, history). The application needs fast key lookups by userId and SQL-like queries on optional fields. Which Azure Cosmos DB API should they choose?

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

Accepted Answer

SQL (Core) API. The SQL (Core) API is the correct choice because it natively supports JSON documents with flexible schemas, enabling fast key-value lookups on the `userId` field (via automatic indexing) and rich SQL-like querying (e.g., `SELECT * FROM c WHERE c.preferences.theme = 'dark'`) on optional fields. It is the only Azure Cosmos DB API that provides a SQL query syntax directly over JSON, making it ideal for mixed workloads of point reads and ad-hoc queries on nested or optional properties.

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MongoDB API

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Cassandra API

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Table API

Question 2

A global social media startup stores user profiles as JSON documents in Azure Cosmos DB. Their application frequently reads profiles by user ID and also runs queries to find users based on location or interests. The workload is read-heavy with high throughput requirements. The operations team notices that query performance degrades during peak hours. Which action would most effectively improve query performance?

Accepted Answer

Increase the provisioned throughput (RU/s). Increasing the provisioned throughput (RU/s) directly allocates more processing capacity to the Cosmos DB container, allowing it to handle higher request volumes and reduce throttling during peak hours. Since the workload is read-heavy and query performance degrades under high throughput demands, raising RU/s is the most effective and immediate action to improve performance.

Answer

Increase the number of containers

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Choose a different API (e.g., switch from SQL API to MongoDB API)

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Switch to a different Azure region

Question 3

A company stores customer reviews for an e-commerce site. Each review contains a product ID, user ID, rating, and optional comments and images. The reviews are written once and rarely updated. The company needs to query reviews by product ID with low latency and also perform simple key-value lookups. They want a cost-effective, serverless solution that requires no scaling management. Which Azure data store should they choose?

Accepted Answer

Azure Table Storage. Azure Table Storage is a cost-effective, serverless NoSQL key-value store that supports simple key-value lookups and querying by partition key (e.g., ProductID) with low latency. It requires no scaling management, as it automatically scales based on demand, and is ideal for immutable, rarely-updated data like customer reviews. The pay-per-request pricing model makes it highly cost-effective for this workload.

Answer

Azure Cosmos DB SQL API

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Azure Blob Storage

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Azure SQL Database

Question 4

A company stores large archives of legal documents in Azure Blob Storage. The documents must remain immutable; they cannot be modified or deleted for 7 years due to regulatory requirements. The data is accessed only for compliance audits, which occur less than once a year. The company wants to minimize storage costs while ensuring immutability and data durability. Which combination of features should they configure?

Accepted Answer

Archive access tier with a time-based retention policy. The Archive access tier provides the lowest storage cost for data that is rarely accessed, such as legal documents accessed less than once a year. A time-based retention policy enforces immutability for a fixed 7-year period, preventing modifications or deletions. This combination meets regulatory requirements while minimizing storage costs.

Answer

Cool access tier with a time-based retention policy

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Hot access tier with versioning enabled

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Archive access tier with legal hold

Question 5

A medical imaging company stores high-resolution MRI scans in Azure Blob Storage. The scans are accessed frequently for the first 6 months after being generated, then rarely after that, but must be available immediately when accessed for comparisons. The company wants to minimize storage costs. Which Azure Blob Storage access tier should they use for scans older than 6 months?

Accepted Answer

Cool access tier. The Cool access tier is ideal for data that is infrequently accessed but must be available immediately when needed. It offers lower storage costs than the Hot tier while maintaining low-latency retrieval, matching the requirement for scans older than 6 months that are rarely accessed but require instant availability.

Answer

Hot access tier

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Archive access tier

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Premium access tier

Question 6

A social networking application needs to store and query relationships between users, such as 'friends of friends'. The application should be able to traverse these relationships efficiently to recommend new connections. Which Azure NoSQL data store and API should they choose?

Accepted Answer

Azure Cosmos DB with the Gremlin API. Azure Cosmos DB with the Gremlin API is the correct choice because Gremlin is a graph traversal language specifically designed for querying highly connected data, such as social network relationships. It allows efficient traversal of edges (e.g., 'friends of friends') using graph algorithms, which is exactly what the application needs for recommending new connections. Other APIs like Table API or services like Blob Storage lack native graph traversal capabilities.

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Azure Cosmos DB with the Table API

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Azure Cache for Redis

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Azure Blob Storage

Question 7

A social media application uses Azure Cosmos DB to store user posts. When a user publishes a new post, they immediately refresh their feed and expect to see their own post right away. However, the application can tolerate temporary staleness for posts from other users. Which Azure Cosmos DB consistency level should the app use for the read operations that display the feed?

Accepted Answer

Session. Session consistency guarantees monotonic reads, writes, and read-your-writes within a single client session. Because the user expects to see their own post immediately after publishing, but can tolerate staleness for others' posts, Session consistency provides the exact guarantee needed: the user's own writes are immediately visible to them, while other users' posts may be slightly stale.

Answer

Strong

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Bounded staleness

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Eventual

Question 8

A social networking application stores user profiles as JSON documents in Azure Cosmos DB. Each profile includes fields such as 'userName', 'email', 'followersCount', and optional 'interests'. The application needs to perform fast point reads by 'userName' (under 10 ms) and also run queries to find all users with a 'followersCount' greater than a certain value. The development team prefers to use a query syntax similar to SQL. Which Azure Cosmos DB API should they choose?

Accepted Answer

Azure Cosmos DB for NoSQL (SQL API). Azure Cosmos DB for NoSQL (SQL API) is the correct choice because it natively supports SQL-like query syntax for querying JSON documents, enabling the required queries such as filtering by 'followersCount'. It also provides fast point reads (under 10 ms) by using the 'userName' field as the partition key, ensuring efficient direct access to individual documents.

Answer

Azure Cosmos DB for MongoDB

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Azure Cosmos DB for Table

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Azure Cosmos DB for Apache Cassandra

Question 9

A smart city application collects sensor data from thousands of devices. Data is ingested as JSON messages containing deviceId, timestamp, and reading value. The application must support fast point reads by deviceId and also run queries to retrieve all readings for a specific deviceId within a time range. The development team prefers a SQL-like query language. Which Azure Cosmos DB API should they choose?

Accepted Answer

SQL (Core) API. The SQL (Core) API is the best choice because it natively supports SQL-like querying, enabling both fast point reads by deviceId (using the partition key) and efficient time-range queries on a specific deviceId. It also provides native JSON support, which aligns with the JSON message format from the sensors, and allows indexing on timestamp for range queries.

Answer

Table API

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MongoDB API

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Cassandra API

Question 10

A social networking application uses Azure Cosmos DB to store user posts. When a user publishes a new post, they immediately refresh their feed and expect to see their own post. However, the application can tolerate temporary staleness for posts from other users (e.g., a few seconds delay). Which Azure Cosmos DB consistency level should the application use for read operations that display the feed?

Accepted Answer

Session. Session consistency is the correct choice because it guarantees that the user who writes a post will read their own write within the same session, while allowing other users to see slightly stale data. This matches the requirement: the author immediately sees their new post, but the application can tolerate a few seconds of staleness for other users' posts. Session consistency uses a session token to ensure monotonic reads and writes for the same client, making it ideal for per-user feed scenarios.

Answer

Strong

Answer

Bounded staleness

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Eventual

Question 11

A global e-commerce company uses Azure Cosmos DB with multiple write regions to handle high traffic from users worldwide. For their order processing system, they must guarantee that once an order is recorded, all subsequent reads from any region see the most up-to-date order status. However, they also need low write latency globally. Which configuration should they choose to meet these requirements?

Accepted Answer

Use single-region writes with strong consistency. Strong consistency with single-region writes ensures that all reads in any region return the most recent write, because Cosmos DB replicates writes synchronously to all regions when strong consistency is configured. This guarantees linearizability: once an order is committed, every subsequent read sees that update. Single-region writes avoid the conflict-resolution overhead of multi-region writes while still providing low write latency within the primary region, and reads from secondary regions are served from locally replicated data that is kept fully consistent.

Answer

Use multi-region writes with strong consistency

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Use multi-region writes with bounded staleness consistency

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Use single-region writes with eventual consistency and implement application-level conflict resolution

Question 12

A social networking application needs to store and query relationships between users, such as 'friends of friends' to recommend new connections. The application must traverse these relationships efficiently. Which Azure NoSQL data store and API should they choose?

Accepted Answer

Azure Cosmos DB with Gremlin API. Azure Cosmos DB with Gremlin API is correct because it provides a graph database model specifically designed for storing and querying highly connected data, such as user relationships. The Gremlin API supports graph traversal queries (e.g., 'friends of friends') natively using the Apache TinkerPop graph traversal language, enabling efficient navigation of edges and vertices without expensive join operations.

Answer

Azure Cosmos DB with MongoDB API

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Azure Table Storage

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Azure Cosmos DB with SQL API

Question 13

A social media application stores user posts as JSON documents in Azure Cosmos DB. Each post includes fields such as postId, userId, content, timestamp, and an array of tags. The development team wants to query posts by userId and timestamp range using a SQL-like syntax. Which Azure Cosmos DB API should they choose?

Accepted Answer

B. Azure Cosmos DB for NoSQL API (Core SQL API). The Azure Cosmos DB for NoSQL API (Core SQL API) is the correct choice because it natively supports SQL-like querying (SELECT, WHERE, ORDER BY) over JSON documents. The team's requirement to query posts by userId and timestamp range using SQL-like syntax is directly supported by this API, which treats each JSON document as an item and allows filtering on nested fields like userId and timestamp. Other APIs either lack native SQL-like syntax or are optimized for different data models (e.g., MongoDB uses a JSON-like query language, Table API uses OData, Cassandra uses CQL).

Answer

A. Azure Cosmos DB for MongoDB API

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C. Azure Cosmos DB for Table API

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D. Azure Cosmos DB for Apache Cassandra API

Question 14

A manufacturing company installs IoT sensors on equipment in a factory. Each sensor sends a reading (device ID, timestamp, temperature, vibration) every second. The application must store these readings with extremely low write latency, support queries for the latest reading per device, and allow range queries over the last hour for a specific device. The development team expects high throughput writes (millions per day) and does not require complex joins. Which Azure data store is most appropriate for this workload?

Accepted Answer

Azure Cosmos DB. Azure Cosmos DB is the most appropriate because it offers single-digit millisecond write and read latencies at any scale, which is critical for the high-throughput, low-latency IoT sensor ingestion described. Its support for automatic indexing and efficient point reads (by device ID and timestamp) enables fast retrieval of the latest reading per device, while its native time-to-live (TTL) and range query capabilities on the timestamp field allow efficient queries over the last hour for a specific device. Additionally, Cosmos DB's schema-agnostic, non-relational model fits the simple key-value structure of sensor readings without requiring complex joins.

Answer

Azure Table Storage

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Azure Blob Storage

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Azure SQL Database

Question 15

A company has a legacy application that requires SMB (Server Message Block) file shares to store and access configuration files. They want to migrate this data to Azure without modifying the application. Which Azure storage solution should they use?

Accepted Answer

Azure Files. Azure Files provides fully managed SMB (Server Message Block) file shares in the cloud, supporting the SMB 3.0 protocol. This allows the legacy application to access configuration files over the network using standard file share paths without any code changes, making it the ideal migration target for lift-and-shift scenarios.

Answer

Azure Blob Storage

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Azure Queue Storage

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Azure Disk Storage