DP-900 Practice Question: Describe considerations for working with non-relational data on Azure

Answer analysis

Option-by-option breakdown

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

• ✗

  Table Storage supports multi-region writes

  Why it's wrong here

  Table Storage is a single-region write service; even with read-access geo-redundant storage, the secondary endpoint is read-only and cannot accept write operations. Therefore, claiming Table Storage supports multi-region writes is incorrect, as write traffic must always target the primary region. This limitation forces applications that need global write scalability to look at services like Cosmos DB.

• ✓

  Cosmos DB provides multiple consistency levels

  Why this is correct

  Cosmos DB exposes five well-defined consistency levels—Strong, Bounded Staleness, Session, Consistent Prefix, and Eventual—that can be selected per request. This tunable consistency model lets developers trade between strict linearizability and lower latency or higher availability, which is a distinct advantage over Table Storage's fixed consistency semantics. The availability of multiple consistency levels is a core architectural consideration when designing globally distributed data solutions.

• ✓

  Cosmos DB supports multi-region writes

  Why this is correct

  With Cosmos DB, write operations can be accepted in any of the regions configured for multi-region write, enabling active-active replication across many geographic regions. This contrasts with Table Storage, where only one region is writable and secondary regions serve as read-only replicas. Multi-region writes reduce write latency for distributed users and provide continuous availability even if an entire write region fails.

• ✗

  Cosmos DB does not support JSON documents

  Why it's wrong here

  Cosmos DB is a multi-model NoSQL database in which JSON is the native wire format for documents, and the core SQL API stores and queries JSON directly. It also supports BSON for MongoDB compatibility, but JSON is always available without translation or transformation. Hence, stating that Cosmos DB does not support JSON is factually incorrect and overlooks its fundamental document model.

• ✓

  Cosmos DB automatically indexes all properties

  Why this is correct

  Cosmos DB's default automatic indexing of all properties is a fundamental technical mechanism that provides immediate query performance across all data attributes. This eliminates the need for manual index management, a significant advantage over Azure Table Storage, which only indexes Partition Key and Row Key. Therefore, the requirement for flexible, performant querying on non-key properties makes automatic indexing a crucial consideration when choosing between these services.

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