DP-900 Describe considerations for working with non-relational data on Azure Practice Test 2 — 15 Questions

Question 1

A social media application stores user sessions as JSON documents. Each session document has fields like sessionId, userId, startTime, endTime, and a list of pageviews. The application needs to quickly retrieve a session by its sessionId and also run queries like 'find all sessions for a user in the last 24 hours' using SQL-like syntax. The data has no fixed schema; different sessions may include additional optional fields like 'deviceType' or 'promotionCode'. Which Azure data store should the company use?

Accepted Answer

Azure Cosmos DB with SQL API. Azure Cosmos DB with SQL API is the correct choice because it natively supports storing JSON documents with flexible schemas, allows fast point reads by sessionId using a unique identifier, and enables SQL-like queries (e.g., filtering by userId and startTime) with automatic indexing. Its schema-agnostic design handles optional fields like deviceType or promotionCode without requiring schema changes, and it provides low-latency reads essential for real-time session retrieval.

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Azure Table Storage

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Azure SQL Database

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Azure Blob Storage

Question 2

A social media company stores user-generated posts as JSON documents. Each post contains fields such as postId, userId, timestamp, and content. The application needs to query posts by userId and timestamp ranges with low latency, and also perform SQL-like queries across all posts. The data volume is growing rapidly and must scale globally. Which Azure data store should the company use?

Accepted Answer

B) Azure Cosmos DB SQL API. Azure Cosmos DB SQL API is the correct choice because it provides native support for querying JSON documents with low-latency, including indexed queries on fields like userId and timestamp. Its global distribution capability ensures data can be replicated across multiple Azure regions for low-latency access worldwide, while its SQL API allows SQL-like queries across all posts, meeting both requirements.

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A) Azure Table Storage

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C) Azure Blob Storage

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D) Azure Cache for Redis

Question 3

A gaming company stores player session data as JSON documents. Each document contains fields like sessionId, userId, startTime, and a varying set of optional fields such as deviceType or campaignId. The application needs to query sessions by userId and startTime range using SQL-like queries, and also by sessionId with low latency. Which Azure Cosmos DB API should the company choose?

Accepted Answer

SQL (Core) API. The SQL (Core) API is the correct choice because it natively supports SQL-like queries over JSON documents, enabling efficient filtering by userId and startTime range. It also provides low-latency point reads by sessionId when a well-designed partition key (e.g., /userId) is used, and it offers automatic indexing of all JSON properties, including optional fields like deviceType or campaignId.

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MongoDB API

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Table API

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Gremlin (Graph) API

Question 4

A healthcare organization stores medical imaging files (DICOM) that are actively used by radiologists for the first 30 days. After 30 days, the files are accessed infrequently for up to 5 years. After 5 years, they must be retained for legal compliance but are accessed very rarely. The organization wants to minimize storage costs. Which strategy should they use to manage the data lifecycle in Azure Blob Storage?

Accepted Answer

Store files in the Hot tier, move to Cool tier after 30 days, then to Archive tier after 5 years.. Option B is correct because it aligns the data lifecycle with the access patterns: Hot tier for frequent initial access, Cool tier for infrequent access after 30 days, and Archive tier for long-term compliance after 5 years. Azure Blob Storage lifecycle management policies can automate these transitions, minimizing costs by using the most cost-effective tier for each phase.

Answer

Store all files in the Hot tier and use lifecycle management to move to the Archive tier after 5 years.

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Store all files in the Archive tier from the beginning to minimize cost.

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Store all files in the Cool tier to balance cost and access.

Question 5

A global e-commerce company needs to store user session data (key-value pairs) for a web application hosted in multiple Azure regions. The data must support low-latency reads and writes (under 10 ms) and be automatically replicated across regions for high availability. The development team also requires the ability to query sessions by user ID using a simple key lookup and occasionally filter by secondary attributes such as timestamp. Which Azure data store should they choose?

Accepted Answer

Azure Cosmos DB. Azure Cosmos DB is correct because it provides globally distributed, multi-region writes with automatic replication, guaranteeing low-latency reads and writes under 10 ms at the 99th percentile. Its key-value API (Table API or SQL API) supports simple key lookups by user ID and secondary indexing on attributes like timestamp, meeting all stated requirements.

Answer

Azure Table Storage

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Azure SQL Database

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Azure Cache for Redis

Question 6

A company stores historical sensor data in Azure Blob Storage. The data is accessed only a few times per year for compliance audits, but when requested, it must be available for reading within 15 minutes. The company wants to minimize storage costs. Which blob access tier should they use?

Accepted Answer

Cool. The Cool tier is the optimal choice because it balances low storage cost with the ability to retrieve data within minutes, meeting the 15-minute availability requirement. Archive would incur a retrieval delay of up to 15 hours, which violates the compliance audit SLA. Hot and Premium tiers are more expensive and unnecessary for data accessed only a few times per year.

Answer

Hot

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Archive

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Premium

Question 7

A social media startup needs to store user sessions as key-value pairs. Each session has a unique session ID, and the data needs to be globally distributed across multiple Azure regions to support low-latency reads for users worldwide. The development team expects heavy write throughput and needs flexible schema. Which Azure data store should they choose?

Accepted Answer

Azure Cosmos DB. Azure Cosmos DB is the correct choice because it provides globally distributed, multi-region writes and reads with turnkey global distribution, supports flexible schema via its document model, and offers multiple consistency levels to balance performance and data integrity. It is designed for high-throughput, low-latency workloads like user sessions, with session IDs serving as natural partition keys for efficient key-value lookups.

Answer

Azure Table Storage

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Azure Blob Storage

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Azure Cache for Redis

Question 8

A social media application stores user profiles as JSON documents. Each profile has standard fields like userId, name, and email, but also optional fields such as education and work history. The application needs to query profiles by userId with low latency and also run SQL-like queries to find all profiles with a specific work history value. Which Azure Cosmos DB API should they choose?

Accepted Answer

SQL (Core) API. The SQL (Core) API is the correct choice because it natively supports querying JSON documents with SQL-like syntax, enabling both low-latency point reads by userId and complex queries on nested fields like work history. It provides automatic indexing of all JSON properties, which ensures efficient execution of queries across optional fields without requiring schema management.

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MongoDB API

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Gremlin (Graph) API

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Table API

Question 9

A company stores customer support chat transcripts as plain text files in Azure Blob Storage. The files are accessed frequently for the first 30 days, then infrequently for the next 2 years, and after that must be retained for 7 years for compliance but are rarely accessed. The company wants to minimize storage costs by automatically moving data through appropriate access tiers. Which Azure Blob Storage lifecycle management policy should they implement?

Accepted Answer

Move blobs from Hot to Cool after 30 days, then to Archive after 2 years. Option A is correct because the lifecycle management policy matches the access pattern: move blobs from Hot (frequent access for first 30 days) to Cool (infrequent access for next 2 years) after 30 days, then to Archive (rare access for 7-year compliance) after 2 years. This minimizes storage costs by using the cheapest tier for each phase while retaining data for the required 7-year compliance period.

Answer

Store all data in Hot tier for the full retention period

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Move blobs from Hot to Archive after 30 days and delete after 2 years

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Store all data in Cool tier for the first 30 days, then move to Archive

Question 10

A gaming application stores player profiles as JSON documents. Each profile has standard fields like playerId, username, and email, but also optional fields such as achievements and gamePreferences. The application needs to query profiles by playerId with low latency and also run SQL-like queries to find players with specific achievements. Which Azure Cosmos DB API should they choose?

Accepted Answer

C: SQL (Core) API. The SQL (Core) API is the best choice because it natively supports JSON documents with flexible schemas (including optional fields like achievements and gamePreferences), provides low-latency point reads by playerId using the id field as the partition key, and enables SQL-like queries (e.g., SELECT * FROM c WHERE ARRAY_CONTAINS(c.achievements, 'specific_achievement')) without requiring a separate indexing or translation layer.

Answer

A: Table API

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B: MongoDB API

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D: Cassandra API

Question 11

A company stores massive amounts of unstructured log data as text files in Azure Blob Storage. The logs are written once and accessed only a few times per month for compliance audits. When accessed, the data must be available within 15 minutes. The company's priority is minimizing storage costs. Which Azure Blob Storage access tier should they use?

Accepted Answer

Cool. The Cool access tier is optimal because the logs are accessed infrequently (a few times per month) but require retrieval within 15 minutes. Cool tier offers lower storage costs than Hot while still supporting near-instant access, making it the best balance for minimizing storage costs with occasional compliance audits.

Answer

Hot

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Archive

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Premium

Question 12

A real-time leaderboard for an online game needs to store player scores and quickly retrieve the top 100 players. The data must update frequently as players achieve new scores, and the application requires sub-millisecond read and write latency. Which Azure data store is best suited for this requirement?

Accepted Answer

Azure Cache for Redis. Azure Cache for Redis is an in-memory data store that provides sub-millisecond read and write latency, making it ideal for real-time leaderboards that require frequent updates and fast retrieval of top scores. Its sorted set data structure (ZADD/ZRANGEBYSCORE) allows efficient insertion of player scores and O(log N) retrieval of the top 100 players without disk I/O overhead.

Answer

Azure Cosmos DB Core (SQL) API

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Azure Table Storage

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Azure Blob Storage

Question 13

A gaming company stores player profiles as JSON documents. Each profile includes standard fields like playerId, username, and email, as well as optional fields such as achievements, gamePreferences, and friendsList. The application needs to look up profiles by playerId with low latency (under 10 ms) and also run SQL-like queries to find players who have a specific achievement. Which Azure Cosmos DB API should they choose?

Accepted Answer

D. SQL (Core) API. The SQL (Core) API is the correct choice because it natively supports JSON documents with flexible schemas (including optional fields like achievements) and provides low-latency point reads by playerId (partition key) under 10 ms. It also enables SQL-like queries (e.g., SELECT * FROM c WHERE ARRAY_CONTAINS(c.achievements, 'specificAchievement')) to find players with a specific achievement, which aligns directly with the requirement.

Answer

A. Table API

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B. Cassandra API

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C. MongoDB API

Question 14

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?

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 15

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)

Answer

Switch to a different Azure region