AZ-900 Describe Azure architecture and services Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✗

  Azure SQL Database

  Why it's wrong here

  Azure SQL Database is a PaaS offering, but it is designed for a single database or elastic pool, and it has significant limitations for migrations of an entire on-premises SQL Server estate: it does not natively support cross-database queries (except via elastic query), has limited SQL Agent functionality, and lacks instance-level features such as SQL Server Agent jobs and common language runtime (CLR) support. These constraints would require application changes and make Managed Instance a more compatible choice for a full database migration.

  When this WOULD be correct

  When a company needs a fully managed, scalable relational database with high availability and built-in intelligence, but does not require cross-database queries or SQL Agent jobs, Azure SQL Database is the appropriate PaaS choice.

• ✓

  Azure SQL Managed Instance

  Why this is correct

  Azure SQL Managed Instance is a fully managed Platform-as-a-Service (PaaS) offering that provides near-complete compatibility with the on-premises SQL Server engine, including support for SQL Server Agent, cross-database queries, and database mail. It also offers automatic backups, patching, and high availability, and it supports network-level isolation via virtual network integration, making it the ideal lift-and-shift target for a set of on-premises databases with minimal application changes.

• ✗

  SQL Server on Azure Virtual Machines

  Why it's wrong here

  SQL Server on Azure Virtual Machines is an Infrastructure-as-a-Service (IaaS) offering where you retain full control over the VM, OS, and SQL Server, but you are also responsible for managing patches, backups, and high availability. Because the requirement specifies a PaaS solution, this IaaS option does not meet the desired level of management (Microsoft handles the platform), even though it offers high compatibility for SQL Server workloads.

  When this WOULD be correct

  If the question required full control over the SQL Server instance, including custom configurations, OS-level access, or the need to run third-party software alongside SQL Server, then SQL Server on Azure Virtual Machines would be the correct answer.

• ✗

  Azure Database for PostgreSQL

  Why it's wrong here

  Azure Database for PostgreSQL is a PaaS service for the PostgreSQL relational database engine, not for Microsoft SQL Server. Migrating existing SQL Server databases to it would require extensive schema changes, rewriting T-SQL queries (especially those using SQL Server-specific features like stored procedures with T-SQL), and re-implementing features such as SQL Agent jobs, making it an unsuitable target for a like-for-like SQL Server migration.

  When this WOULD be correct

  When a company needs a fully managed, open-source PostgreSQL database with built-in high availability and automatic backups, and does not require SQL Server-specific features.

Option-by-option analysis

Why each answer is right or wrong

Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The AZ-900 exam frequently reuses these exact scenarios with slightly different constraints.

Analysis generated from the official AZ-900blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”

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