DP-203 Azure Stream Analytics Input Types Practice Question
Exhibit
Refer to the exhibit.
{
"inputAlias": "input",
"type": "Stream",
"output": {
"outputAlias": "output",
"type": "ReferenceData"
},
"query": "SELECT input.* FROM input JOIN output ON input.ProductId = output.ProductId"
}Refer to the exhibit. You are reviewing an Azure Stream Analytics job query. The job has a stream input and a reference data input. The job is failing with the error 'Reference data input must be of type Reference, not Stream'. What is the cause of the error?
⚠ Common exam trap
Candidates may be misled by the wording 'Reference data input' and think it's about output, but the error is straightforward: the input type is wrong. The trap is overthinking or assuming a complex output issue when the error message directly states the input type must be Reference.
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
✓
The input type is Stream; it should be Reference.
The error 'Reference data input must be of type Reference, not Stream' explicitly indicates that the input configured as Stream should be set to Reference type. In Azure Stream Analytics, reference data inputs are used for static lookup data, and they must be declared as Reference input type. Setting the input type to Stream when it should be Reference causes this error. Therefore, option C is correct. Option D is incorrect because the error message does not relate to output configuration; it is strictly about input type mismatch.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The input alias is incorrect.
Why it's wrong here
An incorrect alias would raise a 'not found' or unresolved-name error, not a type mismatch. The alias resolves correctly; the input it points to is declared as Stream instead of Reference. It tempts because alias typos are a common query fault, but the message explicitly concerns input type.
- ✗
The JOIN syntax is incorrect for reference data.
Why it's wrong here
The JOIN clause itself is valid; the error arises because the input referenced in the join was configured as Stream rather than Reference in the job's inputs. It tempts because join errors often stem from syntax, but here the input type metadata, not the query text, is at fault.
- ✓
The input type is Stream; it should be Reference.
Why this is correct
Stream Analytics classifies each input as Stream or Reference at creation. The query joins reference data, but the input was configured as Stream, so the engine rejects it; changing the input type to Reference resolves the error.
- ✗
The output type is set to ReferenceData; it should be a different type.
Why it's wrong here
Output type is irrelevant to this error, which concerns how an input is declared. The message names the input, not the output, so changing the output type leaves the misconfigured stream input unchanged. It tempts because ReferenceData is a valid output type, but it is never the cause here.
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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.