Getting Data from Databases

Files are a great starting point, but in most professional environments the real data lives inside a database — and connecting Power BI directly to a database instead of exporting files first gives you fresher data, less manual work, and far more control over exactly what gets loaded.

Why Connect to a Database Instead of a File?

When someone exports a database to Excel or CSV and hands you the file, you are already working with data that is hours or days old. Every time the database changes, someone has to remember to re-export. Connecting Power BI directly to the database removes the middleman entirely.

Which Databases Power BI Supports

Power BI has dedicated connectors for dozens of database systems. These are the ones you are most likely to encounter in real-world work.

Import Mode vs DirectQuery Mode

Before you connect to any database you need to make a fundamental decision about how Power BI stores and retrieves the data. There are two modes — Import and DirectQuery — and the choice affects performance, data freshness, and file size for the entire life of the report.

Connecting to SQL Server — Step by Step

SQL Server is the most common database in Microsoft-heavy organisations. The steps below apply to both on-premises SQL Server and Azure SQL Database — the only difference is the server address format.

The Three Authentication Methods

Authentication is the step where you prove to the database that you are allowed to access it. Power BI stores credentials per data source — you only need to enter them once, and Power BI remembers them for future refreshes.

The Navigator — Tables vs Views

After authenticating, the Navigator shows every object in the database you have access to. Databases typically contain both tables and views — and knowing the difference changes which ones you should load.

Writing a Custom SQL Query

Instead of loading entire tables, you can write a SQL SELECT statement inside Power BI to load exactly the rows and columns you need. This reduces the volume of data imported and can dramatically speed up load times on large databases. To use it, expand Advanced options in the connection dialog and paste your query into the SQL statement box.

-- Load only 2024 orders with the columns we actually need
-- Paste this into the Advanced options > SQL statement box

SELECT
    o.OrderID,
    o.OrderDate,
    o.Amount,
    o.Status,
    c.CustomerName,
    c.Region,
    p.ProductName,
    p.Category
FROM
    Orders o
    INNER JOIN Customers c ON o.CustomerID = c.CustomerID
    INNER JOIN Products p ON o.ProductID = p.ProductID
WHERE
    o.OrderDate >= '2024-01-01'
    AND o.Status != 'Cancelled'

Managing Database Credentials

Power BI stores credentials per data source so you do not have to re-enter them on every refresh. But sometimes you need to update them — for example when a password changes or when you want to connect with a different account.

To view or update stored credentials:

1. Home → Transform Data → Data Source Settings
2. Click the data source whose credentials you want to change
3. Click "Edit Permissions"
4. Click "Edit" next to the Credentials section
5. Enter the new username / password → click Save

To delete stored credentials:
→ Data Source Settings → select source → "Clear Permissions"
→ Power BI will prompt for credentials again on next refresh

Important: Desktop credentials are local to your machine.
If you publish to Power BI Service, enter credentials separately:
Workspace → Dataset Settings → Gateway and Cloud Connections

Common Database Connection Errors and Fixes

Practice

Lesson Quiz

Next up — Lesson 8 covers Data Source Settings in depth — how to manage all your connections in one place, update credentials, change source paths, and handle the privacy level settings that block queries when combining data from multiple sources.