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 Cosmos DB

  Why it's wrong here

  Azure Cosmos DB is a globally distributed, multi-model NoSQL database that stores schema-free JSON documents and exposes APIs such as MongoDB, Cassandra, and a SQL-like query syntax. It does not enforce relational constraints or provide the same multi-row ACID semantics as a SQL Server relational engine. Migrating a SQL Server database to Cosmos DB would force a fundamental redesign of tables into documents and rewritten queries, so it cannot be considered a compatible relational migration target.

• ✓

  Azure SQL Database

  Why this is correct

  Azure SQL Database is a fully managed platform-as-a-service relational database built on the SQL Server engine, so it is the natural target for migrating existing SQL Server databases. It automates patching, backups, and high availability while providing intelligent features such as automatic index tuning and performance insights. Because it maintains SQL Server compatibility at the query and schema level, applications can often be moved with minimal code changes, making it the correct choice here.

• ✗

  Azure Database for PostgreSQL

  Why it's wrong here

  Azure Database for PostgreSQL is a fully managed relational database service engineered specifically for the open-source PostgreSQL engine. It does not natively run SQL Server stored procedures, T-SQL syntax, or SQL Server-specific system catalogs, so an existing SQL Server database would need extensive conversion during migration. Since the stated workload is an existing SQL Server database, selecting this service would add unnecessary rework and compatibility risk rather than serving as a direct replacement.

• ✗

  Azure Synapse Analytics

  Why it's wrong here

  Azure Synapse Analytics is an analytics-oriented, massively parallel processing (MPP) data warehousing service designed for complex analytical queries over large data volumes. Its columnar storage and distributed architecture are optimized for batch analytics, not for the low-latency, high-concurrency transaction processing of an OLTP SQL Server database. Replacing an OLTP database with Synapse would require rearchitecting the application and would not preserve transactional integrity the same way.