DP-900 Describe core data concepts Practice Question
A retail company receives real-time data from IoT sensors in its warehouses. Each sensor sends a JSON payload containing a device ID, timestamp, and temperature reading. A data engineer needs to classify this data for storage planning. Which data type best describes the JSON payload?
⚠ Common exam trap
It's easy for candidates to confuse 'structured' with 'has a format' — JSON has a clear structure, but it is not rigidly tabular, so it falls under semi-structured, not structured data.
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
✓
Semi-structured data
The JSON payload is considered semi-structured data because it has organizational properties (key-value pairs, nested structure) that provide a schema, but it does not conform to a rigid tabular schema like a relational database. JSON allows flexible fields and varying data types, which is characteristic 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.
- ✗
Structured data
Why it's wrong here
Structured data requires a fixed, predefined schema, typically organized as rows and columns in a relational table with explicit data types and constraints. JSON payloads from IoT sensors are schema-flexible: fields can be added, omitted, or nested over time, and no relational structure or enforced column definitions exist. This variance violates the core requirement of structured data, so it cannot be classified as structured.
When this WOULD be correct
If the data were in a fixed schema like a CSV file with predefined columns and consistent data types, it would be structured data. For example, a table of customer orders with columns OrderID, CustomerName, and OrderDate.
- ✓
Semi-structured data
Why this is correct
JSON is a classic example of semi-structured data. It uses key-value pairs and can have nested structures, but it does not enforce a rigid schema. This flexibility is ideal for IoT payloads where fields may vary over time.
- ✗
Unstructured data
Why it's wrong here
Unstructured data consists of content with no inherent organizational model, such as raw video files, audio recordings, or freeform text where interpretation requires complex extraction. JSON, however, has a well-defined syntax with key-value pairs, arrays, and nesting that enables a parser to navigate and query the data without ambiguity. That formal, machine-readable structure is the opposite of unstructured data, which is why JSON is correctly categorized as semi-structured.
When this WOULD be correct
A question where the data consists of free-form text documents, images, or audio files without any metadata or schema. For example: 'A company stores customer support chat logs as plain text files. Which data type describes these files?'
- ✗
Relational data
Why it's wrong here
Relational data refers to data stored in tables with rows and columns, typically using a fixed schema. JSON does not fit this definition because it is not tabular and can have varying keys across different payloads.
When this WOULD be correct
If the question described data stored in normalized tables with foreign keys (e.g., customer orders in a SQL database), then 'relational data' 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.
✓Semi-structured dataCorrect answer▾
Why this is correct
JSON is a classic example of semi-structured data. It uses key-value pairs and can have nested structures, but it does not enforce a rigid schema. This flexibility is ideal for IoT payloads where fields may vary over time.
✗Structured dataWrong answer — click to see why▾
Why this is wrong here
JSON payloads have a flexible schema with tags and key-value pairs, which is characteristic of semi-structured data, not the rigid schema of structured data.
★ When this WOULD be the correct answer
If the data were in a fixed schema like a CSV file with predefined columns and consistent data types, it would be structured data. For example, a table of customer orders with columns OrderID, CustomerName, and OrderDate.
Why candidates choose this
Candidates may think JSON is structured because it has keys and values, but they overlook that JSON allows varying fields and nested structures, making it semi-structured.
✗Unstructured dataWrong answer — click to see why▾
Why this is wrong here
JSON payloads have a schema (keys like device ID, timestamp, temperature) but are not rigidly tabular, so they are semi-structured, not unstructured. Unstructured data lacks a predefined data model or schema (e.g., raw text, images).
★ When this WOULD be the correct answer
A question where the data consists of free-form text documents, images, or audio files without any metadata or schema. For example: 'A company stores customer support chat logs as plain text files. Which data type describes these files?'
Why candidates choose this
Candidates may think JSON is just text and thus unstructured, overlooking that JSON has a defined key-value structure. They confuse 'unstructured' with 'non-relational' or 'not in a table'.
✗Relational dataWrong answer — click to see why▾
Why this is wrong here
Relational data implies a strict schema of tables with rows and columns, but the JSON payload has a flexible schema with nested fields, making it semi-structured, not relational.
★ When this WOULD be the correct answer
If the question described data stored in normalized tables with foreign keys (e.g., customer orders in a SQL database), then 'relational data' would be correct.
Why candidates choose this
Candidates may confuse 'relational' with any structured format, or think JSON's key-value pairs resemble relational tables, ignoring the schema flexibility.
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?”
Go deeper
Related to this question
Learn chapter
Data Roles and Core Concepts
Key term
Data
Data is raw, unprocessed information, like numbers, words, or measurements, that can be stored, processed, and analyzed by computers.
Key term
Relational database
A relational database organizes data into tables with rows and columns, where each table relates to others using unique keys, allowing efficient storage, retrieval, and manipulation of structured information.
About these practice questions
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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.