Azure Cosmos DB for Semi-Structured JSON
You need to store semi-structured JSON data from a web application and query it using SQL-like syntax. The solution must support high throughput with low latency. Which Azure data store should you use?
Quick Answer
Azure Cosmos DB is the correct choice because it natively stores semi-structured JSON data and supports SQL-like querying through its core (SQL) API, while guaranteeing high throughput with low latency at the 99th percentile. This makes it ideal for web applications that demand fast, scalable access to document data without sacrificing query flexibility. On the DP-900 exam, this scenario tests your ability to match workload requirements—specifically JSON format, SQL-like syntax, and performance guarantees—to the appropriate Azure data store. A common trap is choosing Azure SQL Database, which handles structured relational data well but lacks the native JSON document model and the single-digit millisecond latency guarantees of Cosmos DB. Another pitfall is Azure Table Storage, which stores key-value pairs but does not support rich SQL-like queries on nested JSON. Remember the memory tip: “Cosmos for JSON, SQL for schema.”
⚠ Common exam trap
Many candidates confuse Azure Blob Storage's ability to store JSON files with the ability to query them using SQL syntax, overlooking that Blob Storage lacks a native query engine for semi-structured data.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Azure Cosmos DB
Azure Cosmos DB is the correct choice because it natively supports semi-structured JSON documents and offers SQL-like querying via its core (SQL) API. It is designed for high throughput and low latency with guaranteed single-digit millisecond response times at the 99th percentile, making it ideal for web applications with demanding performance requirements.
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 Blob Storage
Why it's wrong here
Blob Storage stores unstructured data, not queryable with SQL.
- ✓
Azure Cosmos DB
Why this is correct
Cosmos DB natively supports JSON documents and SQL-like queries.
- ✗
Azure SQL Database
Why it's wrong here
Azure SQL is relational and requires schema mapping for JSON.
- ✗
Azure Table Storage
Why it's wrong here
Table Storage is for key-value, not JSON documents.
Go deeper
Related to this question
Learn chapter
Data Roles and Core Concepts
Key term
Data
Data is raw, unprocessed information, like numbers, words, or measurements, that can be stored, processed, and analyzed by computers.
Key term
Azure Cosmos DB
Azure Cosmos DB is a fully managed, globally distributed NoSQL database service that offers fast reads and writes anywhere in the world with automatic scaling and multiple consistency models.
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Same concept, more angles
1 more way this is tested on DP-900
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. You need to store semi-structured JSON documents from a web application in Azure. The data will be accessed by a key/value lookup. Which Azure data store should you use?
easy- A.Azure Blob Storage
- B.Azure Table Storage
- ✓ C.Azure Cosmos DB
- D.Azure SQL Database
Why C: Azure Cosmos DB is the correct choice because it natively supports semi-structured JSON documents and provides key/value lookup via its partition key mechanism. It offers single-digit millisecond latency for point reads, making it ideal for web application data that needs fast, scalable access by a unique key.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DP-900 practice question is part of Courseiva's free Microsoft certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DP-900 exam.