DP-900 Practice Test 11 — 15 Questions

Question 1

A startup is building a mobile app that allows users to share short text updates. Each update includes a user ID, timestamp, and message text. The development team expects rapid growth and needs a storage solution that can scale horizontally, handle high write throughput, and provide low-latency reads globally. Which Azure data service is most appropriate?

Accepted Answer

Azure Cosmos DB with a multi-master configuration and partition on user ID.. Azure Cosmos DB with a multi-master configuration is the most appropriate choice because it provides global distribution with multiple write regions, enabling horizontal scaling and low-latency reads and writes worldwide. Partitioning on user ID ensures even data distribution and efficient query performance for the app's high write throughput requirements.

Answer

Azure SQL Database with a single database.

Answer

Azure Blob Storage with append blobs.

Answer

Azure Table Storage with user ID as partition key and timestamp as row key.

Question 2

An e-commerce company runs a product inventory database on Azure SQL Database. During a flash sale, write transactions are slow because many read queries are running simultaneously and consuming resources. The company wants to isolate read workloads without modifying application code or database schemas. Which Azure SQL Database feature should they implement?

Accepted Answer

Read scale-out. Read scale-out (B) is correct because it allows read-only queries to be offloaded to a read-only replica of the database, freeing up the primary replica for write transactions. This feature is built into Azure SQL Database at the Business Critical and Premium service tiers, and it requires no application code changes—just a connection string modification to use the `ApplicationIntent=ReadOnly` parameter. It directly addresses the performance bottleneck caused by concurrent read queries during the flash sale.

Answer

Active geo-replication

Answer

Auto-failover groups

Answer

Elastic pools

Question 3

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 4

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

Answer

Bounded staleness

Answer

Eventual

Question 5

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

Answer

Azure Redis Cache

Answer

Azure Blob Storage

Question 6

A university's enrollment system stores data in a single table with columns: EnrollmentID, StudentID, StudentName, CourseID, CourseName, and Grade. Students can take multiple courses, and each course has multiple students. The team notices data redundancy: StudentName is repeated for each enrollment of the same student, and CourseName is repeated for each enrollment in the same course. They want to reduce redundancy while preserving the ability to query all enrollments with student and course details. What is the most appropriate design approach?

Accepted Answer

Normalize the schema by creating separate Students, Courses, and Enrollments tables with foreign keys. Option C is correct because normalizing the schema into separate Students, Courses, and Enrollments tables eliminates data redundancy by storing each student's name and each course's name only once, while using foreign keys to maintain relationships. This preserves the ability to query all enrollments with student and course details via JOIN operations, which is the standard relational database design principle for reducing anomalies and storage overhead.

Answer

Keep the single table but use compression to reduce storage

Answer

Create a view that mirrors the single table but physically store data in separate normalized tables

Answer

Denormalize by adding more columns to the single table

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

Answer

Azure Blob Storage

Answer

Azure Cache for Redis

Question 8

A company has an Azure SQL Database that supports a critical business application in the West US region. They want to ensure that if the primary region becomes unavailable, the database can automatically fail over to a secondary replica in the East US region with minimal data loss. The secondary replica must also be readable to offload some reporting queries when the primary is healthy. Which Azure SQL Database feature should they enable?

Accepted Answer

Active Geo-Replication. Active Geo-Replication creates a readable secondary replica in a different Azure region (East US) that stays synchronized asynchronously with the primary database in West US. In the event of a regional outage, the secondary can be manually or automatically promoted to become the new primary, with minimal data loss (typically a few seconds of transactions). The secondary replica is also readable, allowing reporting queries to be offloaded from the primary while it is healthy.

Answer

Long-term retention backups

Answer

Transparent Data Encryption (TDE)

Answer

Point-in-time restore

Question 9

A company has 12 SQL Server databases, each about 30 GB. The databases experience unpredictable load spikes during the day. The company wants to migrate to Azure SQL Database to reduce administrative overhead and optimize costs by sharing resources among the databases. Which deployment option should they choose?

Accepted Answer

Elastic pool. Elastic pools are designed to share resources (eDTUs or eVCores) among multiple databases with unpredictable, overlapping load spikes. By pooling resources, the company can optimize costs because databases do not all peak simultaneously, and the pool’s total resource allocation is lower than the sum of individual peak requirements. This reduces administrative overhead by providing a single management point for scaling and monitoring all databases in the pool.

Answer

Single database with provisioned DTU

Answer

Managed Instance

Answer

SQL Server on Azure Virtual Machine

Question 10

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 11

A startup is deploying a new application on Azure SQL Database. They expect the database to start at 10 GB but grow to 500 GB over time. They want to be able to scale compute independently of storage and only pay for the compute resources they use. They also want to avoid over-provisioning and automatically pause during idle periods. Which purchasing model and service tier should they choose?

Accepted Answer

vCore-based model with General Purpose serverless tier. The vCore-based General Purpose serverless tier is correct because it allows independent scaling of compute and storage, automatically pauses the database during idle periods to eliminate compute costs, and supports growth from 10 GB to 500 GB without manual intervention. This model aligns with the startup's need to pay only for consumed compute resources and avoid over-provisioning.

Answer

DTU-based model with Basic tier

Answer

vCore-based model with Business Critical provisioned tier

Answer

DTU-based model with Standard tier

Question 12

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?

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 13

An e-commerce company uses Azure SQL Database for its product catalog. During promotional events, the database experiences unpredictable spikes in traffic. The company wants a solution that automatically adjusts compute resources based on demand without manual intervention. Which Azure SQL Database option should they use?

Accepted Answer

C) Serverless compute tier. The Serverless compute tier for Azure SQL Database automatically scales compute resources based on workload demand and pauses the database during idle periods, charging only for storage and used compute. This matches the requirement for handling unpredictable traffic spikes without manual intervention, as it provides instant scaling and cost efficiency for intermittent workloads.

Answer

A) Read replicas

Answer

B) Active geo-replication

Answer

D) Elastic pool

Question 14

A social networking application stores user profiles as JSON documents. Each profile can have different fields (e.g., education, work history, interests) depending on what the user fills in. The application also needs to traverse friend connections as a graph to recommend new friends. The development team wants to use a single Azure Cosmos DB account for both workloads. Which combination of Azure Cosmos DB APIs should they choose?

Accepted Answer

SQL API for profiles and Gremlin API for graph. The SQL API (formerly DocumentDB API) is optimized for storing and querying JSON documents with flexible schemas, making it ideal for user profiles with varying fields. The Gremlin API is designed specifically for graph traversal queries, which is required for recommending friends based on friend connections. Using both APIs on the same Cosmos DB account allows the application to handle both workloads efficiently within a single service.

Answer

MongoDB API for profiles and SQL API for graph

Answer

Gremlin API for both profiles and graph

Answer

Table API for profiles and Gremlin API for graph

Question 15

A company is migrating a 3-TB on-premises SQL Server database to Azure. The database heavily uses cross-database queries with three-part names (e.g., db.schema.table) and relies on SQL Server Agent for scheduled maintenance jobs. They want a fully managed PaaS service with automatic backups and patching, while minimizing application code changes. Which Azure SQL service should they choose?

Accepted Answer

Azure SQL Managed Instance. Azure SQL Managed Instance is the correct choice because it provides near-100% compatibility with on-premises SQL Server, including support for cross-database queries using three-part names (db.schema.table) and SQL Server Agent for scheduled maintenance jobs. As a fully managed PaaS service, it offers automatic backups, patching, and high availability while minimizing application code changes, unlike Azure SQL Database which lacks cross-database query support and SQL Agent.

Answer

Azure SQL Database (single database)

Answer

Azure SQL Database (elastic pool)

Answer

Azure Synapse Analytics dedicated SQL pool