Quick Answer
The answer is to set the output mode to 'Exactly once' in Azure Stream Analytics. This configuration ensures exactly-once semantics for output to Azure SQL Database by leveraging checkpointing and transactional writes, which prevent duplicate records even during retries or failures. On the Microsoft Azure Data Engineer Associate DP-203 exam, this question tests your understanding of Stream Analytics output modes, specifically that 'At least once' is the default but can introduce duplicates, while 'Exactly once' guarantees idempotent delivery to SQL. A common trap is confusing the default mode with the requirement for strict consistency, or assuming invalid modes like 'Best effort' exist. Remember the memory tip: "For SQL, choose 'Exactly once' to avoid the duplicate dance."
This DP-203 practice question tests your understanding of develop data processing. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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.
Your team is developing a real-time data processing solution using Azure Stream Analytics. The input is from Azure Event Hubs. The output must be written to Azure SQL Database. You need to ensure that the processing guarantees exactly-once semantics for the output. Which output configuration should you use?
Set output mode to 'When possible'
Why wrong: Invalid output mode.
Set output mode to 'Exactly once'
Ensures no duplicate writes to SQL Database.
Set output mode to 'At least once'
Why wrong: At least once can produce duplicates.
Set output mode to 'Best effort'
Why wrong: Invalid output mode.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Set output mode to 'Exactly once'
Option C is correct because Azure Stream Analytics supports exactly-once delivery to Azure SQL Database when using the 'Exactly once' output mode. Option A is wrong because 'At least once' is the default and can cause duplicates. Option B is wrong because 'When possible' is not a valid output mode. Option D is wrong because 'Best effort' is not a valid mode.
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.
Set output mode to 'When possible'
Why it's wrong here
Invalid output mode.
Set output mode to 'Exactly once'
Why this is correct
Ensures no duplicate writes to SQL Database.
Related concept
Read the scenario before looking for a memorised answer.
Set output mode to 'At least once'
Why it's wrong here
At least once can produce duplicates.
Set output mode to 'Best effort'
Why it's wrong here
Invalid output mode.
Common exam traps
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Trap categories for this question
Command / output trap
Invalid output mode.
Detailed technical explanation
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
What to study next
Identify which DP-203 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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FAQ
Develop data processing — This question tests Develop data processing — Read the scenario before looking for a memorised answer..
The correct answer is: Set output mode to 'Exactly once' — Option C is correct because Azure Stream Analytics supports exactly-once delivery to Azure SQL Database when using the 'Exactly once' output mode. Option A is wrong because 'At least once' is the default and can cause duplicates. Option B is wrong because 'When possible' is not a valid output mode. Option D is wrong because 'Best effort' is not a valid mode.
Identify which DP-203 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 21, 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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