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

Question 1

A travel booking application stores user itineraries in Azure Cosmos DB using the NoSQL API. Each itinerary document contains: UserID (unique to user), ItineraryID, Destination, BookingDate, and a nested array of Activities. The most common query is: 'Retrieve all itineraries for a specific UserID sorted by BookingDate descending.' To minimize Request Unit (RU) consumption, which partition key should be chosen?

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

Accepted Answer

UserID. UserID is the correct partition key because the most common query filters on UserID, ensuring that all itineraries for a specific user are stored in the same physical partition. This allows the query to target a single partition, minimizing cross-partition queries and reducing Request Unit (RU) consumption. A partition key that aligns with the primary query filter is essential for optimal performance and cost efficiency in Azure Cosmos DB.

Answer

ItineraryID

Answer

Destination

Answer

BookingDate

Question 2

A social media application stores user profiles in Azure Cosmos DB using the NoSQL API. Each profile includes UserID, Name, Email, and an array of Posts. The most common query retrieves a user's profile by UserID. The application requires strong consistency for writes so that once a profile is updated, all subsequent reads see the latest data. To minimize Request Unit (RU) consumption, which partition key should be chosen?

Accepted Answer

UserID. UserID is the correct partition key because it is the primary filter in the most common query (retrieving a profile by UserID), ensuring each query targets a single logical partition. This minimizes cross-partition queries and RU consumption. Additionally, UserID provides high cardinality and even distribution, which prevents hot partitions and supports the required strong consistency for writes.

Answer

Email

Answer

Name

Answer

A synthetic partition key combining UserID and Region

Question 3

A media company stores user profile images in Azure Blob Storage. Regulators require that the images cannot be deleted or overwritten for a period of 90 days after upload. Which Azure Blob Storage feature should the company enable to meet this requirement?

Accepted Answer

B: Immutable storage with a time-based retention policy. Immutable storage with a time-based retention policy (also known as WORM – Write Once, Read Many) prevents blobs from being deleted or overwritten for a specified retention interval. By setting a 90-day policy, the company ensures that user profile images remain unmodifiable and undeletable during that period, directly satisfying the regulatory requirement.

Answer

A: Soft delete

Answer

C: Access tiers (Hot, Cool, Archive)

Answer

D: Lifecycle management rules

Question 4

A travel booking application stores booking data in Azure Cosmos DB using the NoSQL API. Each booking document contains: BookingID (unique), UserID, Destination, TravelDate, Price. The most common query is: 'Retrieve all bookings for a specific UserID, sorted by TravelDate descending.' To minimize Request Unit (RU) consumption, which property should be chosen as the partition key?

Accepted Answer

UserID. UserID is the correct partition key because the most common query filters on UserID, and Cosmos DB routes queries to the exact physical partition(s) containing that UserID's data. This minimizes cross-partition fan-out, reducing RU consumption. A partition key should align with the primary query filter to enable efficient point-read or single-partition query execution.

Answer

BookingID

Answer

Destination

Answer

TravelDate

Question 5

A media company stores high-definition video files for on-demand streaming. The files are accessed very frequently for the first 30 days after upload, then rarely (about once per month) for the next year, and after one year they are rarely accessed but must be retained for compliance (about once per year). Which set of access tier transitions minimizes cost while meeting access requirements?

Accepted Answer

Hot for 30 days, then Cool for 11 months, then Archive. It aligns the Azure Blob Storage access tier transitions with the access pattern: Hot tier for the first 30 days of frequent access, Cool tier for the next 11 months of monthly access, and Archive tier after one year for rare compliance access. This minimizes cost by moving data to progressively cheaper storage tiers as access frequency drops, while still meeting the access requirements (Cool supports monthly access, Archive supports yearly access with retrieval time).

Answer

Hot for 30 days, then Archive immediately

Answer

Cool for 30 days, then Cool for 11 months, then Archive

Answer

Hot for 365 days, then Archive

Question 6

A company stores JSON documents for a product catalog. Each document has a flexible schema because different product categories have different attributes. The catalog is read-heavy and requires low-latency lookups by product ID. The company expects to handle millions of products and needs to serve customers globally with low latency. Which Azure NoSQL data store should they choose?

Accepted Answer

Azure Cosmos DB. Azure Cosmos DB is the correct choice because it is a globally distributed, multi-model NoSQL database that natively supports JSON documents with flexible schemas, provides single-digit-millisecond latency for read-heavy workloads via automatic indexing, and offers turnkey global distribution across Azure regions to serve customers worldwide with low latency.

Answer

Azure Table Storage

Answer

Azure Blob Storage

Answer

Azure SQL Database

Question 7

A gaming application requires a high-performance leaderboard that stores player scores and retrieves the top 10 scores quickly. The data does not require complex queries or a fixed schema. The leaderboard must support updates as new scores are submitted. Which Azure data store is most appropriate for this scenario?

Accepted Answer

Azure Cache for Redis. Azure Cache for Redis is the most appropriate choice because it provides an in-memory data structure store with native support for sorted sets (via the ZADD and ZRANGE commands), which are ideal for maintaining a real-time leaderboard. It can handle high-throughput score updates and retrieve the top 10 scores in O(log(N)) time, meeting the low-latency and performance requirements without needing a fixed schema.

Answer

Azure Cosmos DB with SQL API

Answer

Azure Table storage

Answer

Azure Blob Storage

Question 8

A social media application stores user posts in Azure Cosmos DB using the NoSQL API. Each document includes: PostID (unique), UserID, Timestamp, Content. The most common query is: 'Get all posts for a specific UserID, sorted by Timestamp descending.' Which partition key should be chosen to distribute load evenly across physical partitions while also supporting this query efficiently?

Accepted Answer

UserID. UserID is the correct partition key because it evenly distributes write operations across physical partitions (each user has a unique ID) and directly supports the most common query: filtering by UserID. With UserID as the partition key, the query 'Get all posts for a specific UserID, sorted by Timestamp descending' becomes a single-partition query (using the partition key in the WHERE clause), which is efficient and avoids cross-partition fan-out. This design also allows Cosmos DB to use the Timestamp field as a sort key within each logical partition, enabling efficient sorting without additional indexing overhead.

Answer

PostID

Answer

Timestamp

Answer

Content

Question 9

A company develops an IoT device registry that stores device metadata as JSON documents. Each device has a unique DeviceID, and the attributes vary per device type (e.g., sensors, actuators). The application requires low-latency reads by DeviceID and needs global distribution to support devices worldwide. The team wants to use a fully managed NoSQL database in Azure. Which API should they choose for Azure Cosmos DB?

Accepted Answer

SQL API. The SQL API (formerly DocumentDB API) is the native API for Azure Cosmos DB, providing full support for querying JSON documents with a SQL-like syntax. It offers the lowest latency reads by ID (point reads) and native global distribution, making it ideal for a device registry where each device has a unique DeviceID and variable attributes. The SQL API also supports indexing all properties automatically, which is critical for the varied device types.

Answer

MongoDB API

Answer

Cassandra API

Answer

Table API

Question 10

A company must archive customer correspondence PDFs that are rarely accessed but must be retained for seven years. The documents must be available for read within seconds if requested. Which Azure Blob Storage access tier should be used to minimize storage cost while meeting the availability requirement?

Accepted Answer

Cool. The Cool tier is optimal because it balances low storage cost with high availability for data that is infrequently accessed but must be retrievable within seconds. It offers the same low-latency retrieval as the Hot tier (milliseconds) but at a lower storage price, making it ideal for archived correspondence that still requires immediate read access.

Answer

Hot

Answer

Archive

Answer

Premium

Question 11

A global social media app uses Azure Cosmos DB (NoSQL API) to store user profile data. The app is read-heavy and requires the fastest possible read performance worldwide. The data is updated by users and eventual consistency is acceptable because immediate consistency is not critical for profile views. Which consistency level should they choose to minimize read latency?

Accepted Answer

Eventual. Eventual consistency offers the lowest read latency because it allows reads from any replica without waiting for confirmation that the data is the most recent version. Since the app is read-heavy and eventual consistency is acceptable, this consistency level minimizes latency by not requiring any synchronization or staleness bounds.

Answer

Strong

Answer

Bounded staleness

Answer

Session

Question 12

A company develops an IoT device registry that stores device metadata as JSON documents. Each device has a unique DeviceID, and the attributes vary per device type (e.g., sensors, actuators). The application requires low-latency reads by DeviceID and needs global distribution to support devices worldwide. Which Azure Cosmos DB API should they choose to natively support JSON documents with flexible schema?

Accepted Answer

Azure Cosmos DB SQL API. The Azure Cosmos DB SQL API (formerly DocumentDB) is the correct choice because it provides native support for storing and querying JSON documents with flexible schema, allowing each device document to have a unique DeviceID and varying attributes per device type. It offers low-latency reads by DeviceID via direct point reads using the partition key, and supports global distribution through multi-region writes and automatic replication, meeting the worldwide deployment requirement.

Answer

Azure Cosmos DB Table API

Answer

Azure Cosmos DB for MongoDB API

Answer

Azure Cosmos DB Gremlin API

Question 13

A global online gaming company needs a data store for player game session logs. Each log record has a SessionID (unique), PlayerID, GameID, StartTime, EndTime, and a JSON payload containing variable game state details. The company requires low-latency writes for millions of concurrent sessions and wants to query by PlayerID and time range. Schema flexibility is important because game state details change frequently. 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 low-latency writes (single-digit milliseconds at the 99th percentile) for millions of concurrent sessions, supports schema-flexible JSON documents that can accommodate frequently changing game state payloads, and enables efficient queries by PlayerID and time range using a composite index or a partition key like PlayerID combined with a time-based sort order.

Answer

Azure Table Storage

Answer

Azure Blob Storage

Answer

Azure SQL Database

Question 14

A manufacturing company collects sensor data from thousands of IoT devices. Each sensor reading includes a timestamp, device ID, and a variable set of measurements (e.g., temperature, pressure, vibration) that differ by device type. The company needs to store this data in a globally distributed NoSQL database that supports low-latency writes and flexible schema. 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 is a globally distributed, multi-model database service that supports low-latency writes at scale, a flexible schema (schemaless), and automatic indexing of variable sensor measurements. Its multi-region write capability and configurable consistency levels meet the requirements of high-throughput IoT ingestion from thousands of devices.

Answer

Azure SQL Database

Answer

Azure Cache for Redis

Answer

Azure Database for PostgreSQL

Question 15

A mobile gaming company stores player session data as key-value pairs. Each player has a unique PlayerID, and the application needs to read/write the player's current level and score with very low latency. The data does not require complex queries, and the schema (attributes per player) can vary. The company wants a fully managed, globally distributed NoSQL database. Which Azure data store should they choose?

Accepted Answer

Azure Cosmos DB Table API. Azure Cosmos DB Table API is the correct choice because it provides a fully managed, globally distributed NoSQL database that supports key-value data with schema flexibility. It offers low-latency reads and writes (single-digit milliseconds at the 99th percentile) and automatic global distribution, making it ideal for storing player session data with varying attributes per player.

Answer

Azure SQL Database

Answer

Azure Blob Storage

Answer

Azure Cache for Redis