DP-900 Describe core data concepts Practice Question
A company stores customer data in a relational table with fixed columns: CustomerID (integer), FirstName (string), LastName (string), Email (string). They also store product images as JPEG files in Azure Blob Storage, and customer feedback as JSON documents where each document may contain fields such as rating, comment, and optional metadata. Which of the following correctly classifies these data types?
⚠ Common exam trap
Many candidates confuse 'semi-structured' with 'unstructured' because JSON looks like free-form text, but its key-value structure with optional fields makes it semi-structured, not unstructured.
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
✓
Relational table – structured, JPEG – unstructured, JSON – semi-structured
A relational table with fixed columns and data types (CustomerID, FirstName, LastName, Email) stores structured data with a rigid schema. JPEG files in Azure Blob Storage are binary blobs with no internal structure that a database can interpret, making them unstructured. JSON documents with optional fields (like rating, comment, metadata) have a flexible schema that can vary per document, which is the definition of semi-structured data.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Relational table – structured, JPEG – unstructured, JSON – semi-structured
Why this is correct
Relational tables enforce a fixed schema of columns, data types, and constraints, which is the defining trait of structured data. JPEG files are binary image encodings with no queryable schema or row/column organization, so they are unstructured. JSON documents use named fields and nested objects but allow fields to vary across documents, making them semi-structured rather than fully rigid or schema-free.
- ✗
Relational table – structured, JPEG – semi-structured, JSON – unstructured
Why it's wrong here
JPEG is not semi-structured because it lacks named fields, tags, or hierarchical key-value pairs that can be parsed for querying; it is a byte stream with headers and compressed pixel data. JSON is not unstructured either, since its objects consist of keys and values that can be validated and queried with tools like JSONPath. Relational tables are correctly labeled structured in this option, but the two misclassifications of the file and document types make the entire answer wrong.
When this WOULD be correct
If the question defined JPEG files as having metadata tags (like EXIF) that are semi-structured, and JSON documents as lacking any schema (e.g., arbitrary text), then B would be correct.
- ✗
Relational table – semi-structured, JPEG – unstructured, JSON – structured
Why it's wrong here
Calling a relational table semi-structured ignores the rigid, predefined schema that every row must conform to before any data is written, which is the essence of structured storage. JPEG is correctly called unstructured because it contains no queryable schema. JSON is not structured in the relational sense; its schema is implicit and can vary per document, so while it has some structure, it is properly categorized as semi-structured.
When this WOULD be correct
Option C would be correct if the relational table had variable columns or allowed schema changes (making it semi-structured), and the JSON documents had a fixed schema enforced by the application (making them structured). For example, a table with optional columns and JSON with required fields.
- ✗
Relational table – unstructured, JPEG – structured, JSON – semi-structured
Why it's wrong here
Classifying a relational table as unstructured is incorrect because its schema is defined up front via DDL, with typed columns and relationships enforced by the database engine. JPEG files also cannot be structured, as they are compressed binary streams whose content only has meaning to an image decoder, not to a query engine. Only the JSON classification is accurate here, as it permits flexible key-value fields, so this option fails on the first two assignments.
When this WOULD be correct
If the question described a relational table storing unstructured data like BLOBs, JPEG files with EXIF metadata (structured), and JSON documents with a fixed schema enforced by a validation tool (structured), then D would be correct.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The DP-900 exam frequently reuses these exact scenarios with slightly different constraints.
✓Relational table – structured, JPEG – unstructured, JSON – semi-structuredCorrect answer▾
Why this is correct
Relational tables enforce a fixed schema of columns, data types, and constraints, which is the defining trait of structured data. JPEG files are binary image encodings with no queryable schema or row/column organization, so they are unstructured. JSON documents use named fields and nested objects but allow fields to vary across documents, making them semi-structured rather than fully rigid or schema-free.
✗Relational table – structured, JPEG – semi-structured, JSON – unstructuredWrong answer — click to see why▾
Why this is wrong here
JPEG files are binary data without inherent structure, making them unstructured, not semi-structured. JSON documents have a flexible schema (key-value pairs), classifying them as semi-structured, not unstructured.
★ When this WOULD be the correct answer
If the question defined JPEG files as having metadata tags (like EXIF) that are semi-structured, and JSON documents as lacking any schema (e.g., arbitrary text), then B would be correct.
Why candidates choose this
Candidates may confuse 'semi-structured' with 'unstructured' due to the flexibility of JSON, or mistakenly think image files have inherent structure because they can be parsed.
✗Relational table – semi-structured, JPEG – unstructured, JSON – structuredWrong answer — click to see why▾
Why this is wrong here
Option C incorrectly classifies the relational table as semi-structured (it is structured with fixed columns) and JSON as structured (JSON is semi-structured as it allows flexible fields). JPEG images are correctly classified as unstructured.
★ When this WOULD be the correct answer
Option C would be correct if the relational table had variable columns or allowed schema changes (making it semi-structured), and the JSON documents had a fixed schema enforced by the application (making them structured). For example, a table with optional columns and JSON with required fields.
Why candidates choose this
Candidates may confuse 'semi-structured' with 'structured' because JSON has a key-value format that appears organized, and they might think a relational table is 'semi-structured' if they consider data types as flexible, overlooking the fixed schema.
✗Relational table – unstructured, JPEG – structured, JSON – semi-structuredWrong answer — click to see why▾
Why this is wrong here
JPEG files are binary data without inherent structure, making them unstructured, not structured. JSON documents have a flexible schema with optional fields, classifying them as semi-structured, not unstructured.
★ When this WOULD be the correct answer
If the question described a relational table storing unstructured data like BLOBs, JPEG files with EXIF metadata (structured), and JSON documents with a fixed schema enforced by a validation tool (structured), then D would be correct.
Why candidates choose this
Candidates may confuse 'structured' with 'binary' or think JPEG files have a rigid format (structured), and mistakenly view JSON as unstructured due to its flexible schema.
Analysis generated from the official DP-900blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Quick reference
Azure Blob Storage Tier Comparison
| Tier | Storage Cost | Retrieval Cost | Latency | Use Case |
|---|---|---|---|---|
| Hot | Highest | Lowest | Immediate | Active data, frequent reads |
| Cool | Lower | Higher | Immediate | Data accessed < once / month |
| Cold | Lower still | Higher | Immediate | Data accessed < once / quarter |
| Archive | Lowest | Highest + rehydration delay | Hours | Long-term compliance retention |
Go deeper
Related to this question
Learn chapter
Data Roles and Core Concepts
Key term
Schema
A schema is a blueprint or logical structure that defines how data is organized, stored, and accessed in a database or information system.
Key term
Structured data
Structured data is information that is organized in a predefined format, typically in rows and columns, making it easy to search, process, and analyze by computers.
About these practice questions
This DP-900 question is part of Courseiva's 820-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
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.