The Azure Data Fundamentals exam (DP-900) validates foundational knowledge of core data concepts and how they map to Microsoft Azure data services. These five concepts are the spine of the exam outline.
1. Core Data Concepts#
Core data concepts make up roughly 25–30% of DP-900. Service questions get easier once this vocabulary is automatic.
Tip
Data can stream in real time, land in batches (lakes), or sit in structured stores (databases). DP-900 tests whether you can match the pattern to the Azure service.
Types of Data#
| Type | Structure | Example | Azure Storage |
|---|---|---|---|
| Structured | Fixed schema, rows & columns | SQL tables, spreadsheets | Azure SQL Database |
| Semi-structured | Flexible schema, self-describing | JSON, XML, key-value pairs | Cosmos DB, Blob Storage |
| Unstructured | No predefined structure | Images, videos, documents | Blob Storage, Data Lake |
Note
Semi-structured data is often called "NoSQL" data. It has some organizational properties (like tags or keys) but doesn't conform to a rigid tabular structure.
Batch vs Real-Time Processing#
| Processing Type | Description | Use Case | Azure Service |
|---|---|---|---|
| Batch | Process accumulated data on a schedule | Nightly reports, monthly billing | Azure Data Factory, Synapse |
| Real-time (Stream) | Process data immediately as it arrives | Fraud detection, live dashboards | Azure Stream Analytics, Event Hubs |
Data Roles#
| Role | Primary Responsibility | Key Skills |
|---|---|---|
| Database Administrator (DBA) | Manage databases, security, backup, performance | SQL, database management |
| Data Engineer | Build pipelines, transform data, ensure quality | ETL, programming, cloud services |
| Data Analyst | Analyze data, create reports and visualizations | SQL, Power BI, Excel |
| Data Scientist | Build predictive models, machine learning | Python, statistics, ML frameworks |
Warning
Don't confuse Data Engineer with DBA! DBAs manage database systems; Data Engineers build the pipelines that move and transform data between systems.
Test Your Understanding#
A company stores customer profiles as JSON documents where each customer has different fields. What type of data is this?
2. Relational Databases on Azure#
Relational database concepts make up 20-25% of the exam. Understanding how tables relate and Azure's SQL offerings is crucial.
Relational Database Fundamentals#
Relational databases organize data into tables (also called relations) with:
- Rows — Individual records (e.g., one customer, one order)
- Columns — Attributes of the data (e.g., name, email, date)
- Primary Key — Unique identifier for each row
- Foreign Key — Column referencing another table's primary key
┌─────────────────────────────┐ ┌─────────────────────────────┐
│ Customers │ │ Orders │
├─────────────────────────────┤ ├─────────────────────────────┤
│ CustomerID (PK) │◄────│ CustomerID (FK) │
│ Name │ │ OrderID (PK) │
│ Email │ │ OrderDate │
└─────────────────────────────┘ │ TotalAmount │
└─────────────────────────────┘
Tip
Normalization is the process of organizing data to reduce redundancy. Instead of repeating customer info in every order, we store it once in the Customers table and reference it via foreign key.
Azure Relational Data Services#
| Service | Description | Best For |
|---|---|---|
| Azure SQL Database | Fully managed PaaS database | New cloud-native apps, simple migrations |
| Azure SQL Managed Instance | Near 100% SQL Server compatibility | Lift-and-shift migrations, SQL Agent jobs |
| SQL Server on Azure VMs | Full SQL Server control (IaaS) | Apps requiring OS-level access |
| Azure Database for MySQL/PostgreSQL | Managed open-source databases | Apps built on MySQL or PostgreSQL |
Note
Azure SQL Database is a PaaS offering — Microsoft manages patching, backups, and high availability. SQL Managed Instance adds features like cross-database queries and SQL Agent for easier migrations.
Key SQL Concepts#
| Concept | Purpose |
|---|---|
| Views | Virtual tables defined by a query; simplify complex queries |
| Indexes | Speed up data retrieval at the cost of storage and write performance |
| Stored Procedures | Precompiled SQL code that can be executed repeatedly |
In a relational database, what ensures each row in a table can be uniquely identified?
3. Non-Relational Data on Azure#
Non-relational (NoSQL) data services make up 15-20% of the exam. These services handle data that doesn't fit neatly into tables.
Azure Cosmos DB#
Azure Cosmos DB is Microsoft's globally distributed, multi-model NoSQL database. Key features:
- Global distribution — Replicate data to any Azure region
- Multi-model — Support multiple APIs for different data models
- Guaranteed low latency — Single-digit millisecond reads and writes
- Automatic scaling — Throughput scales with demand
Cosmos DB APIs#
| API | Data Model | Use Case |
|---|---|---|
| API for NoSQL (Core) | JSON documents | Most scenarios, native SQL-like queries |
| API for MongoDB | JSON documents | Apps using MongoDB drivers |
| API for Apache Cassandra | Wide-column | High-scale, column-family workloads |
| API for Apache Gremlin | Graph | Relationship-heavy data (social networks) |
| API for Table | Key-value | Simple key-value lookups, Azure Table migration |
Tip
When in doubt, choose API for NoSQL — it's the native, most feature-complete option and uses SQL-like syntax familiar to most developers.
Partition Keys#
Cosmos DB uses partition keys to distribute data across physical partitions:
- Choose a property with high cardinality (many unique values)
- Queries should filter by partition key when possible
- Avoid "hot partitions" where one partition gets most traffic
Warning
A bad partition key choice can create performance bottlenecks! For example, partitioning IoT data by DeviceID is problematic if one device sends 90% of all data.
Azure Blob Storage#
Azure Blob Storage stores unstructured data like images, videos, and backups:
| Access Tier | Use Case | Storage Cost | Access Cost |
|---|---|---|---|
| Hot | Frequently accessed data | Higher | Lower |
| Cool | Infrequently accessed (30+ days) | Lower | Higher |
| Cold | Rarely accessed (90+ days) | Lower | Higher |
| Archive | Long-term backup (180+ days) | Lowest | Highest |
Azure Data Lake Storage Gen2#
Combines blob storage with a hierarchical namespace for big data analytics:
- Hierarchical namespace — True directory structure for better performance
- Hadoop compatible — Works with Azure Databricks, HDInsight, Synapse
- Cost effective — Blob storage pricing with data lake capabilities
A company stores product reviews as JSON documents with varying structures. Which Cosmos DB API is most appropriate?
4. Data Analytics on Azure#
Analytics concepts make up 25-30% of the exam. Understanding data warehousing and Azure's analytics services is essential.
Data Warehouse vs Data Lake#
| Characteristic | Data Warehouse | Data Lake |
|---|---|---|
| Data Type | Structured, processed | Raw (structured, semi, unstructured) |
| Schema | Schema-on-write (defined before loading) | Schema-on-read (applied when querying) |
| Users | Business analysts, BI tools | Data scientists, engineers |
| Purpose | Reporting, dashboards, BI | Machine learning, exploration |
Note
Modern architectures often use both: raw data lands in the data lake, is processed, and loaded into the data warehouse for reporting. This is called the Lakehouse pattern.
Azure Synapse Analytics#
Azure Synapse is an integrated analytics service that brings together:
- Dedicated SQL pools — Data warehousing with massively parallel processing
- Serverless SQL pools — Query data lake files with T-SQL (pay per query)
- Apache Spark pools — Big data processing and machine learning
- Pipelines — Data integration and orchestration (like Data Factory)
Tip
Dedicated SQL pools can be paused when not in use to save compute costs while retaining your data. Great for development environments or periodic reporting.
Azure Data Factory#
Azure Data Factory (ADF) is a cloud ETL service for data integration:
- Pipelines — Orchestrate data movement and transformation
- Activities — Individual operations (copy data, run scripts)
- Linked Services — Connections to data sources and destinations
- Datasets — Representations of data structures
Azure Databricks#
A collaborative Apache Spark platform for big data and machine learning:
- Notebooks — Interactive code development
- Clusters — Managed Spark compute
- Delta Lake — Reliable data lake with ACID transactions
- MLflow — Machine learning lifecycle management
What is the key difference between schema-on-write and schema-on-read?
5. Data Visualization with Power BI#
Understanding how data flows from source to dashboard is critical for the exam.
Power BI Components#
| Component | Description | Example |
|---|---|---|
| Dataset | Data model connecting to sources, defines relationships | Sales data from SQL + Excel |
| Report | Collection of visualizations on one or more pages | Sales report with charts, tables |
| Dashboard | Single-page view with pinned visuals from reports | Executive KPI overview |
Data Sources → Dataset → Report(s) → Dashboard
│ │ │ │
SQL, Excel Data Model Charts Pinned Tiles
Tip
Reports can have multiple pages and interactive visualizations. Dashboards are single-page and show tiles pinned from multiple reports for a quick overview.
Power BI Workflow#
- Connect — Link to data sources (databases, files, services)
- Transform — Clean and shape data with Power Query
- Model — Define relationships, measures, calculated columns
- Visualize — Create charts, tables, and interactive reports
- Share — Publish to Power BI Service, create dashboards
Key Power BI Concepts#
| Concept | Description |
|---|---|
| Power Query | ETL tool for data transformation within Power BI |
| DAX | Data Analysis Expressions — formula language for calculations |
| Relationships | Connections between tables in the data model |
| Row-Level Security (RLS) | Filter data based on user identity |
Note
Power BI Desktop is for authoring reports. Power BI Service (cloud) is for sharing, collaboration, and dashboards. Power BI Mobile apps consume reports on devices.
In Power BI, what is the correct order from data source to end-user view?
Know your range before test day#
DP-900 is concept-heavy. Use a short diagnostic to see which data domains need drills before you book the sitting.
- Timed diagnostic with domain-level breakdown
- Clear signal on what to drill next
- Practice free; timed sittings and readiness range on Pro
Take the free DP-900 assessment →
Next step: Start practicing free on the DP-900 hub, or sit a short diagnostic first.