DP-900 Practice Test 8 — 10 Questions

Question 1

A logistics company tracks shipment locations using GPS devices that send JSON data with fields: shipmentId, latitude, longitude, timestamp, speed. The data is stored in Azure Cosmos DB using the Core (SQL) API. The application needs to query all shipments that are currently within a specific geographic bounding box and have a speed greater than 0. Which query approach should they use to efficiently retrieve the data?

Accepted Answer

Use ST_WITHIN to specify the bounding box polygon and add a WHERE clause for speed.. Option B is correct because Azure Cosmos DB's Core (SQL) API supports geospatial queries using the ST_WITHIN function, which efficiently checks if a point (latitude/longitude) lies inside a polygon (bounding box). Adding a WHERE clause for speed > 0 further filters the results, and Cosmos DB can leverage a composite index on the geospatial field and speed to optimize query performance.

Answer

Use a BETWEEN clause on latitude and longitude and a WHERE clause for speed.

Answer

Use ST_DISTANCE to measure distance from a center point and also filter on speed.

Answer

Use the IN operator to list all acceptable coordinate pairs and a speed filter.

Question 2

A global gaming company develops a multiplayer game. Player profile data (username, email, preferences) is stored as simple key-value pairs and must be accessible with single-digit millisecond latency from any region. Game session logs are stored as JSON documents with varying fields (session ID, player actions, timestamps) and must be queryable by player ID and timestamp range using SQL-like syntax. The company wants to use a single Azure database service for both workloads. Which combination of Azure Cosmos DB APIs should they choose?

Accepted Answer

Table API for profiles and SQL API for logs. Option A is correct because the Table API provides a simple key-value store ideal for low-latency profile lookups, while the SQL API supports querying JSON documents with SQL-like syntax, enabling efficient queries on game session logs by player ID and timestamp range. This combination meets both workloads within a single Azure Cosmos DB account.

Answer

SQL API for both profiles and logs

Answer

MongoDB API for profiles and Cassandra API for logs

Answer

Table API for both profiles and logs

Question 3

A social media application displays the number of posts each user has created. After a user submits a new post, the count must reflect the update across all servers within a few seconds. Which data consistency model best describes this requirement?

Accepted Answer

Eventual consistency. Eventual consistency is correct because the requirement allows a few seconds for the update to propagate across all servers, meaning the system does not guarantee immediate uniformity but will converge to the same count eventually. This is typical in distributed systems like social media applications where high availability and partition tolerance are prioritized over immediate consistency, often using techniques like asynchronous replication.

Answer

Strong consistency

Answer

Sequential consistency

Answer

Causal consistency

Question 4

A company plans to migrate a 500 GB SQL Server database from on-premises to Azure SQL Database. They require minimal downtime during the migration. Which approach should they use?

Accepted Answer

Use Azure Database Migration Service with online migration mode. Azure Database Migration Service (DMS) with online migration mode is the correct approach because it supports minimal-downtime migrations by continuously replicating ongoing changes from the source SQL Server to Azure SQL Database using the transactional replication technology. This allows the source database to remain operational during the migration, and only a brief cutover is needed at the end to switch applications to the target.

Answer

Export a BACPAC file and import to Azure SQL Database

Answer

Use Azure Site Recovery to replicate the database

Answer

Create a full database backup and restore to Azure SQL Database

Question 5

A mobile game stores player achievements in Azure Cosmos DB. Each player has a PlayerID, and achievements are stored as JSON documents with varying fields. The most common query retrieves all achievements for a specific player. To ensure low latency and efficient throughput, which property should be chosen as the partition key?

Accepted Answer

PlayerID. PlayerID is the correct partition key because the most common query retrieves all achievements for a specific player, and partitioning on PlayerID ensures that all documents for a given player are stored in the same physical partition. This allows the query to target a single partition, minimizing cross-partition queries and providing low latency and efficient throughput.

Answer

Timestamp

Answer

AchievementType

Answer

Region

Question 6

A ride-sharing application uses Azure Cosmos DB for trip data. Each trip record contains TripID (unique), DriverID, RiderID, TripDate, and other details. The most common query retrieves all trips for a specific driver within a given date range. Which partition key should be chosen to minimize Request Unit (RU) consumption and ensure even data distribution?

Accepted Answer

DriverID. DriverID is the optimal partition key because the most common query filters on DriverID and a date range. Partitioning by DriverID ensures that all trips for a specific driver are stored in the same physical partition, making the query a single-partition operation that consumes minimal Request Units (RUs). It also provides even data distribution across partitions because each driver generates a roughly similar number of trips, avoiding hot spots.

Answer

TripID

Answer

TripDate

Answer

RiderID

Question 7

A logistics company uses an online system to process incoming delivery requests one at a time, updating the database immediately upon each transaction. They also run a weekly job that analyzes thousands of delivery records to identify average delivery times and trends. Which set of terms correctly classifies these two workloads?

Accepted Answer

OLTP and OLAP. The first workload processes individual delivery requests with immediate database updates, which is the definition of Online Transaction Processing (OLTP). The second workload runs a weekly job analyzing thousands of records for trends and averages, which is Online Analytical Processing (OLAP). These two terms correctly classify the transactional and analytical workloads described.

Answer

Batch processing and real-time processing

Answer

Relational and non-relational

Answer

Structured and semi-structured

Question 8

A retail company uses Azure SQL Database for its sales transaction table, which contains over 500 million rows. Queries that filter by OrderDate are slow because the database scans the entire table. The database administrator decides to implement table partitioning on the OrderDate column. What is the primary benefit of this partitioning strategy?

Accepted Answer

It improves query performance by enabling partition elimination, where only relevant partitions are scanned.. Table partitioning in Azure SQL Database divides a large table into smaller, manageable segments based on a partition key (here, OrderDate). The primary benefit is partition elimination: queries with filters on OrderDate can scan only the relevant partition(s) instead of the entire 500-million-row table, drastically reducing I/O and improving query performance.

Answer

It reduces the total storage required by compressing older partitions.

Answer

It enforces referential integrity between partitions automatically.

Answer

It eliminates the need for indexes on the partitioned column.

Question 9

A mobile app stores user preferences in Azure Cosmos DB using the NoSQL API. The app frequently reads a single user's profile by user ID (the partition key). The development team wants the fastest possible read performance globally and is willing to accept that reads might not reflect the latest write immediately. Which consistency level should they choose to minimize read latency?

Accepted Answer

Eventual. Eventual consistency offers the lowest read latency because it allows reads to return data from any replica without waiting for confirmation that the write has been fully replicated. Since the app can tolerate stale reads (i.e., not reflecting the latest write immediately), Eventual consistency eliminates the synchronization overhead required by stronger models, making it the fastest choice for global read performance.

Answer

Strong

Answer

Bounded staleness

Answer

Session

Question 10

A healthcare application stores patient medical records as JSON documents. Each document contains a variable set of fields depending on the patient's conditions. The application needs to query records by any field and support high write throughput. Which Azure data store is most appropriate?

Accepted Answer

Azure Cosmos DB with SQL API. Azure Cosmos DB with SQL API is the most appropriate choice because it natively supports storing and querying JSON documents with variable schemas, enabling efficient queries on any field. Its multi-model architecture and configurable indexing policies allow high write throughput while maintaining low-latency queries, which is critical for healthcare applications with dynamic patient records.

Answer

Azure Blob Storage

Answer

Azure Synapse Analytics

Answer

Azure Table Storage