DP-203 Design and implement data storage Practice Question
You are designing a data storage solution for a global e-commerce company. The company needs to store clickstream data from millions of users with high write throughput and low-latency reads for real-time analytics. The data is semi-structured and includes nested JSON objects. Which Azure data store should you recommend?
⚠ Common exam trap
Watch out — candidates often choose Azure Table Storage because it is a NoSQL store, but they overlook its lack of native JSON support and sub-10ms latency guarantees, confusing its simple key-value model with the richer document capabilities of Cosmos DB.
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 provides a multi-model, globally distributed database service with guaranteed single-digit-millisecond read and write latencies at the 99th percentile, making it ideal for high-throughput clickstream ingestion and real-time analytics. Its native support for semi-structured data and nested JSON objects via the SQL API (or MongoDB API) allows direct storage and querying of complex event payloads without schema flattening. Additionally, Cosmos DB offers automatic indexing and tunable consistency levels to balance performance and data freshness for global e-commerce scenarios.
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 this is correct
Azure Cosmos DB satisfies the high write throughput, low-latency read, and semi-structured nested JSON requirements through its schema-agnostic document model and partition-based horizontal scale. Its multi-region replication supports the global footprint, while the SQL API queries nested objects natively without transformation, unlike columnar or relational stores.
- ✗
Azure Table Storage
Why it's wrong here
Azure Table Storage stores entities as key-attribute pairs, so nested JSON objects must be flattened and there is no native support for the low-latency analytical query patterns real-time clickstream analytics demands. It is tempting because it offers cheap, high-throughput storage for semi-structured data, and would suit simple key-based lookups rather than nested analytics.
- ✗
Azure SQL Database
Why it's wrong here
Azure SQL Database is a relational engine requiring a fixed schema, so nested JSON must be shredded or stored as opaque text, and it cannot sustain the write throughput of millions of clickstream users. It is tempting because it offers low-latency queries and JSON functions, and would be correct for structured transactional workloads.
- ✗
Azure Blob Storage
Why it's wrong here
Azure Blob Storage provides cheap, scalable object storage but no native indexing or query engine, so low-latency reads over nested JSON for real-time analytics require an additional compute layer. It is tempting because it handles high write throughput and semi-structured data well, and would be the correct choice for storing raw files for later batch processing.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DP-203 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-203 exam.