Classifying Data Types in Azure Data Fundamentals
A company stores customer data in a relational database with columns like CustomerID, Name, and Email. They also store product images as JPEG files in Azure Blob Storage, and customer feedback as JSON documents that contain varying fields such as rating, comments, and optional metadata. Which of the following correctly orders these data types from most structured to least structured?
Quick Answer
The correct order from most structured to least structured is relational data, JSON, and images. This ordering reflects the fundamental classification of data types in Azure Data Fundamentals: relational data enforces a rigid schema with fixed columns and constraints, making it fully structured; JSON documents are semi-structured because they use key-value pairs with optional fields like metadata, allowing flexibility without a predefined schema; and JPEG images are unstructured binary data with no inherent organizational structure. On the DP-900 exam, this concept tests your ability to distinguish between structured, semi-structured, and unstructured data across Azure services like Azure SQL Database, Cosmos DB, and Blob Storage. A common trap is misplacing JSON as unstructured due to its variable fields, but remember that any data with tags or keys—even optional ones—is semi-structured. For a quick memory tip, think of a filing cabinet: relational data is a labeled folder with fixed slots, JSON is a folder with sticky notes that can be added or removed, and images are loose photographs tossed in a drawer.
⚠ Common exam trap
Test-takers frequently confuse 'semi-structured' with 'unstructured' or assume images have more structure than JSON because they are stored in a named file, but the key distinction is schema rigidity: relational > JSON > binary blobs.
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 data, JSON, images
Relational data (CustomerID, Name, Email) is the most structured because it enforces a fixed schema with defined data types and constraints. JSON documents (customer feedback) are semi-structured: they have a flexible schema with optional fields like metadata, but still use key-value pairs. Images (JPEG files) are unstructured binary data with no inherent schema. Option C correctly orders them from most structured (relational) to least structured (images).
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 data, images, JSON
Why it's wrong here
Images are unstructured, not semi-structured like JSON, so this order is incorrect.
When this WOULD be correct
If the question asked to order data types by storage size (e.g., from largest to smallest) or by typical access latency, then images (large files) might come before JSON (smaller documents). For example: 'Order the following data types by average file size: relational data (rows), JSON documents, images.'
- ✗
Images, JSON, relational data
Why it's wrong here
Images are unstructured and relational data is structured, so this is reversed.
When this WOULD be correct
If the question asked to order data types from least structured to most structured, then images (unstructured), JSON (semi-structured), relational data (structured) would be correct, making option B the right answer.
- ✓
Relational data, JSON, images
Why this is correct
Correct order: structured (relational), semi-structured (JSON), unstructured (images).
- ✗
JSON, relational data, images
Why it's wrong here
Relational data is more structured than JSON, so this order is incorrect.
When this WOULD be correct
If the question asked for the order from least structured to most structured, then D (JSON, relational data, images) would be correct because images are least structured, JSON is semi-structured, and relational data is most structured.
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 data, JSON, imagesCorrect answer▾
Why this is correct
Correct order: structured (relational), semi-structured (JSON), unstructured (images).
✗Relational data, images, JSONWrong answer — click to see why▾
Why this is wrong here
Images (JPEG) are unstructured binary data, not semi-structured. JSON documents have some structure (key-value pairs) but are less structured than relational data with fixed schema. Thus, ordering relational > JSON > images is correct, not relational > images > JSON.
★ When this WOULD be the correct answer
If the question asked to order data types by storage size (e.g., from largest to smallest) or by typical access latency, then images (large files) might come before JSON (smaller documents). For example: 'Order the following data types by average file size: relational data (rows), JSON documents, images.'
Why candidates choose this
Candidates may mistakenly think JSON is unstructured because it allows varying fields, or they may confuse 'structured' with 'binary format', placing images as more structured than JSON.
✗Images, JSON, relational dataWrong answer — click to see why▾
Why this is wrong here
Images (JPEG) are unstructured binary data, while JSON documents have some structure (key-value pairs), so JSON is more structured than images. Ordering images before JSON is incorrect.
★ When this WOULD be the correct answer
If the question asked to order data types from least structured to most structured, then images (unstructured), JSON (semi-structured), relational data (structured) would be correct, making option B the right answer.
Why candidates choose this
Candidates may mistakenly think JSON is completely unstructured because it allows varying fields, or they may confuse the order direction and assume images are more structured than JSON.
✗JSON, relational data, imagesWrong answer — click to see why▾
Why this is wrong here
JSON documents have a schema (even if flexible) and are semi-structured, while images are unstructured binary data. The order from most to least structured should be relational (structured), JSON (semi-structured), images (unstructured), not JSON then relational.
★ When this WOULD be the correct answer
If the question asked for the order from least structured to most structured, then D (JSON, relational data, images) would be correct because images are least structured, JSON is semi-structured, and relational data is most structured.
Why candidates choose this
Candidates may mistakenly think JSON is less structured than relational data because it allows varying fields, but they overlook that images are completely unstructured, leading them to place JSON before relational data.
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
Blob storage
Blob storage is a cloud service for storing large amounts of unstructured data, such as text or binary data, like documents, images, and videos.
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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Same concept, more angles
8 more ways this is tested on DP-900
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A logistics company collects sensor data from delivery trucks. Each sensor sends a JSON message that includes a fixed set of core fields (truck ID, timestamp) but also includes optional fields such as temperature, humidity, and engine diagnostics depending on the sensor type. The JSON structure varies between messages. How should this data be classified?
medium- A.Structured data
- ✓ B.Semi-structured data
- C.Unstructured data
- D.Relational data
Why B: The JSON messages contain a fixed set of core fields (truck ID, timestamp) but also include optional fields that vary per message, meaning the data has a flexible schema. This mixture of structured fields and variable attributes is the defining characteristic of semi-structured data, which does not require a rigid schema like a relational table but still has organizational properties (e.g., key-value pairs). In Azure, this type of data is commonly stored in services like Azure Cosmos DB or Azure Blob Storage with JSON format.
Variation 2. A logistics company collects data from fleet sensors. Each sensor sends a JSON message containing the vehicle ID, timestamp, and a variable set of measurements such as engine temperature, tire pressure, and fuel level. The structure of the JSON message differs between sensor types and sometimes includes optional fields. How should this data be classified?
easy- A.Structured data
- ✓ B.Semi-structured data
- C.Unstructured data
- D.Relational data
Why B: The data is semi-structured because it conforms to a schema (JSON format with fields like vehicle ID and timestamp) but allows variability in structure, such as optional fields and different sets of measurements per sensor type. This flexibility is a hallmark of semi-structured data, which does not require a rigid tabular schema like structured data but still contains tags or markers to separate data elements.
Variation 3. A marketing company collects data from social media feeds including text posts, images, and videos. The data arrives in various formats with no fixed structure or schema. This type of data is best described as:
easy- A.A) Structured data
- B.B) Semi-structured data
- ✓ C.C) Unstructured data
- D.D) Relational data
Why C: Unstructured data lacks a predefined data model or schema, making it ideal for storing text posts, images, and videos that arrive in varied formats. Unlike structured or semi-structured data, unstructured data cannot be easily organized into rows and columns or parsed with tags, which is why option C is correct for this scenario.
Variation 4. A retail company collects data from online transactions including order ID, customer details, product IDs, quantities, and timestamps. The data is stored in a relational database and used for order processing and inventory management. Which characteristic of this data makes it structured?
easy- ✓ A.It is stored in rows and columns with a predefined schema.
- B.It is stored as key-value pairs.
- C.It is stored in JSON format with variable fields.
- D.It is stored in unstructured text files.
Why A: Structured data is defined by a fixed schema where each entity (e.g., orders) is stored in rows and columns with predefined data types (e.g., INT for order ID, VARCHAR for customer details). This relational model enforces consistency and enables efficient querying via SQL for order processing and inventory management.
Variation 5. A company collects temperature readings from IoT sensors every second. Each reading includes a timestamp, sensor ID, and temperature value. The data is used for real-time monitoring and historical trend analysis. Which type of data is this most likely classified as?
medium- ✓ A.Structured data
- B.Semi-structured data
- C.Unstructured data
- D.Streaming data
Why A: The data consists of timestamp, sensor ID, and temperature value, each with a defined data type and relationship, fitting a tabular schema (rows and columns) typical of relational databases. This structured format enables efficient querying for real-time monitoring and historical trend analysis using SQL-based systems like Azure SQL Database or Azure Synapse Analytics.
Variation 6. A hospital collects patient data from multiple sources. Source A stores patient vitals as a continuous stream of readings from wearable devices. Source B stores historical medical records in a relational database with fixed columns (PatientID, Diagnosis, AdmissionDate). Source C stores doctor's notes as unstructured text files. Which statement correctly describes the structure of data from these sources?
medium- A.Source A is semi-structured, Source B is structured, Source C is unstructured.
- ✓ B.Source A is structured, Source B is structured, Source C is unstructured.
- C.Source A is structured, Source B is unstructured, Source C is semi-structured.
- D.Source A is semi-structured, Source B is semi-structured, Source C is unstructured.
Why B: Source A stores patient vitals as a continuous stream from wearable devices, which is structured data because it typically consists of time-stamped numeric readings with a fixed schema (e.g., timestamp, heart rate, blood pressure). Source B uses a relational database with fixed columns (PatientID, Diagnosis, AdmissionDate), which is classic structured data. Source C contains unstructured text files (doctor's notes) with no predefined schema. Therefore, Option B correctly identifies all three sources.
Variation 7. A company stores customer contact information in a table with columns for CustomerID, Name, Email, and Phone. They also store customer support chat transcripts as plain text files. Which of the following correctly classifies these data types?
easy- A.Both are structured data
- B.Customer contact information is structured; chat transcripts are semi-structured
- ✓ C.Customer contact information is structured; chat transcripts are unstructured
- D.Both are semi-structured
Why C: Customer contact information stored in a table with columns like CustomerID, Name, Email, and Phone is structured data because it has a fixed schema with rows and columns. Chat transcripts stored as plain text files have no predefined schema or organization, making them unstructured data. Therefore, option C correctly classifies the contact info as structured and the chat transcripts as unstructured.
Variation 8. A company stores customer information in a table with columns CustomerID, Name, Address, and PhoneNumber. Every row has values for all these columns, and the data follows a fixed schema. Which type of data does this represent?
easy- A.Unstructured data
- B.Semi-structured data
- ✓ C.Structured data
- D.Streaming data
Why C: Structured data conforms to a fixed schema where each row has the same columns and data types. The table with CustomerID, Name, Address, and PhoneNumber, where every row contains values for all columns, perfectly fits this definition. This is typical of relational database tables (e.g., in Azure SQL Database) where the schema is enforced at the table level.
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.