Quick Answer
The answer is Azure SQL Database and Azure Cosmos DB. This combination directly addresses the need for polyglot persistence in an e-commerce application by pairing a relational engine for transactional order data with a NoSQL document store for flexible product catalogs. Azure SQL Database enforces ACID compliance and referential integrity, which is critical for order processing, while Azure Cosmos DB provides low-latency, schema-agnostic document storage ideal for high-read-throughput catalogs that evolve frequently. On the DP-203 exam, this scenario tests your understanding of workload-specific data stores and the principle of choosing the right tool for each job. A common trap is assuming a single database like Azure SQL Database can handle both workloads, but polyglot persistence explicitly requires mixing models. Memory tip: think “Orders need ACID, Catalogs need speed” — SQL for structure, Cosmos for flexibility.
This DP-203 practice question tests your understanding of design and implement data storage. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Which TWO Azure services can be used to implement a polyglot persistence architecture for an e-commerce application that requires both a relational database for orders and a document database for product catalogs?
Azure Cache for Redis
Why wrong: In-memory cache, not a durable data store.
Azure SQL Database
Suitable for relational data like orders.
Azure Cosmos DB
Supports document models for product catalogs.
Azure Table Storage
Why wrong: Key-value store, not document or relational.
Azure Data Lake Storage Gen2
Why wrong: File/object storage, not suitable for transactional data.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Azure SQL Database
Azure SQL Database is a relational database service that supports ACID transactions and structured querying, making it ideal for storing and managing e-commerce order data with strong consistency and referential integrity. Azure Cosmos DB is a multi-model NoSQL database that provides document database capabilities with flexible schemas and low-latency access, perfectly suited for product catalogs that require high read throughput and schema evolution. Together, they enable a polyglot persistence architecture by using the best storage model for each workload.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
Azure Cache for Redis
Why it's wrong here
In-memory cache, not a durable data store.
Azure SQL Database
Why this is correct
Suitable for relational data like orders.
Related concept
Read the scenario before looking for a memorised answer.
Azure Cosmos DB
Why this is correct
Supports document models for product catalogs.
Related concept
Read the scenario before looking for a memorised answer.
Azure Table Storage
Why it's wrong here
Key-value store, not document or relational.
Azure Data Lake Storage Gen2
Why it's wrong here
File/object storage, not suitable for transactional data.
Common exam traps
The trap here is that candidates often confuse Azure Table Storage with a document database, but Table Storage is a key-value store without native JSON support or rich querying, whereas Cosmos DB provides a true document database with SQL API and indexing.
Detailed technical explanation
Polyglot persistence leverages multiple database technologies within the same application to match data storage to access patterns. Azure SQL Database uses SQL Server's query optimizer and indexing to enforce relational constraints, while Azure Cosmos DB's document model stores product catalog items as JSON with automatic indexing and tunable consistency levels (e.g., session or eventual) to balance performance and correctness. In practice, an e-commerce app might use Azure SQL Database for order transactions requiring atomicity and Cosmos DB for product catalog reads that can tolerate slightly stale data for lower latency.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
What to study next
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FAQ
Design and implement data storage — This question tests Design and implement data storage — Read the scenario before looking for a memorised answer..
The correct answer is: Azure SQL Database — Azure SQL Database is a relational database service that supports ACID transactions and structured querying, making it ideal for storing and managing e-commerce order data with strong consistency and referential integrity. Azure Cosmos DB is a multi-model NoSQL database that provides document database capabilities with flexible schemas and low-latency access, perfectly suited for product catalogs that require high read throughput and schema evolution. Together, they enable a polyglot persistence architecture by using the best storage model for each workload.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 24, 2026
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.
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