DP-900 Identify considerations for relational data on Azure Practice Test 11 — 15 Questions

Question 1

A company uses Azure SQL Database to store order data. The Orders table has millions of rows with columns: OrderID (primary key, clustered), CustomerID, OrderDate, Status, TotalAmount. Queries frequently filter on OrderDate and Status, and sort results by OrderDate descending. Which indexing strategy will most improve query performance for these filters and sort?

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

Accepted Answer

Create a nonclustered index on (OrderDate DESC, Status) and include TotalAmount. Creates a covering nonclustered index on (OrderDate DESC, Status) that directly supports the frequent filter on OrderDate and Status and the ORDER BY OrderDate DESC. Including TotalAmount as a non-key column makes the index covering, so all needed columns come from the index without key lookups, maximizing query performance.

Answer

Create a clustered index on OrderDate

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Create a nonclustered index on Status alone

Answer

Create a clustered columnstore index on the table

Question 2

A company runs an e-commerce platform on Azure SQL Database. The database handles many concurrent transactions (OLTP). The business team runs complex reporting queries on the same database during business hours, which slows down the transactional workload. The company wants to offload the reporting queries to a separate read-only copy of the database to avoid performance impact. Which Azure SQL Database feature should they enable?

Accepted Answer

Read scale-out. Read scale-out (C) is the correct feature because it allows Azure SQL Database to offload read-only workloads, such as complex reporting queries, to a separate read-only replica. This is achieved by using the `ApplicationIntent=ReadOnly` connection string parameter, which routes queries to a secondary replica, thereby preventing performance impact on the primary transactional (OLTP) workload. This feature is specifically designed for scenarios where you need to isolate reporting from high-concurrency OLTP operations without requiring a separate database copy.

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Hyperscale service tier

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Geo-replication

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Elastic query

Question 3

A company is migrating an on-premises SQL Server database to Azure SQL Managed Instance. The database has a large fact table that is partitioned by date (monthly partitions) to improve query performance and simplify data archiving. The company wants to maintain the same partitioning strategy in Azure to avoid rewriting queries. Which feature in Azure SQL Managed Instance should they use to achieve this?

Accepted Answer

Table partitioning with partition functions and schemes. Azure SQL Managed Instance supports table partitioning using partition functions and partition schemes, which is the same feature available in SQL Server. This allows you to define monthly partitions on the fact table using a date column, preserving the existing partitioning strategy and query logic without modification. The partition function maps rows to partitions based on the date boundary values, and the partition scheme assigns those partitions to filegroups.

Answer

Sharding across multiple Azure SQL Managed Instances

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Index partitioning only

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Federated tables

Question 4

A company uses Azure SQL Database for an e-commerce application. The Orders table has millions of rows. Queries frequently filter on OrderDate and OrderStatus, and sort by OrderDate descending. Which indexing strategy will most improve query performance?

Accepted Answer

Create a non-clustered index on (OrderDate DESC, OrderStatus) and keep the existing clustered index on OrderID. Creates a covering index for the most common query pattern: filtering on OrderDate and OrderStatus, and sorting by OrderDate descending. By specifying DESC in the index key, the index is ordered in the same direction as the sort, allowing SQL Server to avoid a sort operation and retrieve rows in order directly from the index. This non-clustered index can satisfy the query entirely without touching the clustered index (OrderID), reducing I/O and improving performance.

Answer

Create a clustered index on OrderDate and a non-clustered index on OrderStatus

Answer

Create a non-clustered index on (OrderDate, OrderStatus) and keep the existing clustered index on OrderID

Answer

Create a clustered index on OrderID and a non-clustered index on (OrderStatus, OrderDate)

Question 5

A library management system uses Azure SQL Database. The Books table has 500,000 rows with columns: BookID (primary key, clustered), Title, Author, ISBN, PublishedYear, CopiesAvailable. Queries frequently filter by Author and then sort results by PublishedYear in descending order. The queries also return the Title and CopiesAvailable columns. Which indexing strategy will most improve query performance for these operations?

Accepted Answer

Create a nonclustered index on (Author, PublishedYear DESC) and include (Title, CopiesAvailable). It creates a covering nonclustered index on (Author, PublishedYear DESC) that directly supports the filter (Author) and sort (PublishedYear DESC) operations. Including Title and CopiesAvailable as non-key columns makes the index covering, meaning all required columns are in the index leaf level, so SQL Server can satisfy the query entirely from the index without key lookups to the clustered index. This minimizes I/O and improves query performance.

Answer

Create a nonclustered index on Author only

Answer

Create a nonclustered index on PublishedYear DESC

Answer

Keep only the existing clustered index on BookID

Question 6

A retail company uses Azure SQL Database for an order management system. The Orders table has columns: OrderID (primary key, clustered), CustomerID, OrderDate, TotalAmount. Queries frequently filter on CustomerID and OrderDate, and sort results by OrderDate in descending order. The queries also return the TotalAmount. Which indexing strategy will most improve query performance for these operations?

Accepted Answer

Create a nonclustered index on (CustomerID, OrderDate DESC) INCLUDE (TotalAmount).. It creates a covering nonclustered index that supports both the filter predicates (CustomerID and OrderDate) and the sort order (OrderDate DESC) while including TotalAmount as an included column to avoid key lookups. This index allows SQL Server to satisfy the query entirely from the index pages, minimizing I/O and improving performance.

Answer

Maintain the existing clustered index on OrderID only.

Answer

Create a nonclustered index on (OrderDate DESC) INCLUDE (CustomerID, TotalAmount).

Answer

Create a clustered columnstore index on the entire table.

Question 7

A small online retailer wants to migrate its single on-premises SQL Server database to Azure. They require a fully managed relational database service with built-in high availability, automated backups, and no need to manage virtual machines. They do not need features like multiple databases with cross-database queries or SQL Agent. Which Azure service should they choose?

Accepted Answer

Azure SQL Database. Azure SQL Database is a fully managed Platform-as-a-Service (PaaS) relational database that provides built-in high availability (99.99% SLA with zone-redundant configuration), automated backups with point-in-time restore, and eliminates the need to manage virtual machines or operating system patches. It is the ideal choice for a single database migration when features like cross-database queries and SQL Agent are not required.

Answer

Azure SQL Managed Instance

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SQL Server on Azure Virtual Machines

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Azure Database for MySQL

Question 8

A company uses Azure SQL Database for an order management system. The Orders table has millions of rows with columns: OrderID (primary key, clustered), CustomerID, OrderDate, Status (e.g., 'Shipped', 'Pending'), TotalAmount. Queries frequently filter on OrderDate and Status, and sort results by OrderDate in descending order. They return several columns including TotalAmount. Which indexing strategy will most improve query performance?

Accepted Answer

Create a nonclustered index on (OrderDate DESC, Status) INCLUDE (CustomerID, TotalAmount). It creates a covering nonclustered index that matches the query's filter and sort order exactly. The index on (OrderDate DESC, Status) allows SQL Server to seek directly on OrderDate and Status, and the descending order avoids a sort operation for the ORDER BY OrderDate DESC clause. Including CustomerID and TotalAmount as included columns makes this a covering index, so the query can be satisfied entirely from the index without key lookups to the clustered index, which is critical for performance on a table with millions of rows.

Answer

Create a clustered index on (OrderDate, Status)

Answer

Create a nonclustered index on (Status) only

Answer

Create a columnstore index on the entire table

Question 9

A company uses Azure SQL Database for an e-commerce platform. The Orders table has columns: OrderID (primary key, clustered), CustomerID, OrderDate, TotalAmount. Queries frequently filter on CustomerID and a range of OrderDate, and then sort the results by OrderDate in descending order. The queries also return the TotalAmount column. Which indexing strategy will most improve query performance for these operations?

Accepted Answer

Create a nonclustered index on (CustomerID, OrderDate DESC) with included column TotalAmount. It creates a covering index that matches the query's filter predicates (CustomerID equality, OrderDate range) and sort order (OrderDate DESC). By including TotalAmount as an included column, the index fully satisfies the query without needing to access the clustered index (key lookup), minimizing I/O and improving performance.

Answer

Create a nonclustered index on (OrderDate DESC, CustomerID) with included column TotalAmount

Answer

Change the clustered index to be on (CustomerID, OrderDate DESC)

Answer

Create a nonclustered index on (OrderDate DESC) without including TotalAmount

Question 10

A company runs a mission-critical SQL Server database on-premises. They plan to migrate to Azure SQL Database and need to choose the appropriate service tier. The database is currently 500 GB and is expected to grow to 8 TB within two years. The workload is read-heavy with many concurrent users, and they require fast scaling of compute resources without significant downtime. Which Azure SQL Database service tier should they choose?

Accepted Answer

Hyperscale. Hyperscale is the correct choice because it supports databases up to 100 TB, far exceeding the expected 8 TB growth, and provides fast scaling of compute resources without downtime by using a distributed architecture with separate compute and storage nodes. Its read-heavy workload with many concurrent users benefits from Hyperscale's multiple readable replicas and buffer pool extension, ensuring high performance and availability.

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General Purpose

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Business Critical

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Serverless

Question 11

A retail company runs analytical reporting queries on a large Sales table in Azure SQL Database. The table contains over 100 million rows and is updated daily with new transactions. The queries aggregate data by product and month, scanning millions of rows per query. The company wants to significantly reduce query execution time without changing the queries. Which indexing strategy should they implement?

Accepted Answer

Create a clustered columnstore index on the table.. A clustered columnstore index is ideal for large data warehousing and analytical workloads because it stores data column-wise, enabling high compression and batch-mode processing. For queries that aggregate millions of rows by product and month, columnstore indexes dramatically reduce I/O and CPU by scanning only the necessary columns and using segment elimination, which directly addresses the requirement to reduce query execution time without changing the queries.

Answer

Create a nonclustered index on the ProductID column.

Answer

Create a filtered index for the most recent month's data.

Answer

Create a clustered rowstore index (default) and rely on database compression.

Question 12

A company runs an e-commerce application on Azure SQL Database. The database has a table named Orders with columns: OrderID (int, primary key), CustomerID (int), OrderDate (datetime), TotalAmount (decimal). The application frequently runs the following query: SELECT * FROM Orders WHERE CustomerID = 12345 AND OrderDate BETWEEN '2025-01-01' AND '2025-01-31' ORDER BY OrderDate DESC. The table contains 10 million rows. Which index would best optimize this query?

Accepted Answer

A nonclustered index on (CustomerID, OrderDate DESC) including TotalAmount as included column.. The query filters on both CustomerID and OrderDate, so a composite nonclustered index on (CustomerID, OrderDate DESC) allows SQL Server to perform an index seek on CustomerID and then an ordered range scan on OrderDate, avoiding a sort operation. Including TotalAmount as an included column makes the index covering, so the query can be satisfied entirely from the index without key lookups to the clustered index.

Answer

A nonclustered index on OrderDate only.

Answer

A clustered index on (OrderDate, CustomerID).

Answer

A nonclustered index on (OrderDate DESC) only.

Question 13

An e-commerce company uses Azure SQL Database for order processing. The Orders table has columns: OrderID (unique, clustered index), CustomerID, OrderDate, Status, TotalAmount. A common query filters on CustomerID and OrderDate, and sorts by OrderDate descending. The query also returns TotalAmount. Which indexing strategy will produce the best query performance?

Accepted Answer

Create a nonclustered index on (CustomerID, OrderDate DESC) INCLUDE (TotalAmount). It creates a covering index that supports both the equality filter on CustomerID and the range/sort on OrderDate DESC. By including TotalAmount as an included column, the query can be satisfied entirely from the nonclustered index without key lookups to the clustered index, minimizing I/O and improving performance.

Answer

Create a nonclustered index on (OrderDate) INCLUDE (CustomerID, TotalAmount)

Answer

Create a nonclustered index on (OrderDate DESC) INCLUDE (CustomerID, TotalAmount)

Answer

Create a nonclustered index on (CustomerID) INCLUDE (OrderDate, TotalAmount)

Question 14

A company runs a global e-commerce application on Azure SQL Database. The application has a read-intensive workload with millions of users querying product details simultaneously. The database is experiencing high read latency during peak hours due to the volume of concurrent read requests. The company wants to scale read performance without changing the application code and without affecting write operations. Which Azure SQL Database feature should they implement?

Accepted Answer

Active geo-replication. Active geo-replication creates readable secondary replicas of the Azure SQL Database in different Azure regions. By configuring read-only routing to these secondaries, the application can offload read queries from the primary database, scaling read performance without any code changes and without impacting write operations on the primary.

Answer

Elastic pools

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In-memory OLTP

Answer

Columnstore indexes

Question 15

A company plans to migrate an on-premises SQL Server database to Azure. The database currently uses SQL Server Agent jobs for scheduled maintenance tasks, cross-database queries, and query store for performance tuning. The database size is 500 GB and needs to scale to 10 TB eventually. They want a managed service that requires minimal application changes. Which Azure relational database 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 SQL Server Agent jobs, cross-database queries, and Query Store, while being a fully managed PaaS service. It allows scaling up to 10 TB (up to 16 TB with some configurations) with minimal application changes, as it uses the same T-SQL surface area and network configuration (VNet) as on-premises SQL Server.

Answer

Azure SQL Database (single database)

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Azure SQL Database Hyperscale

Answer

Azure Database for SQL Server