Direct Connectivity in Power BI

Exploring DirectQuery and Live Connection

Learning Outcome

5

Choose the correct mode for different business scenarios

4

Compare performance, freshness, and flexibility

3

Identify benefits and limitations of each mode

2

Understand how each mode works internally

1

Explain Import, DirectQuery, and Live Connection clearly

  • What datasets are in Power BI
     

  • That reports rely on data connections
     

  • That refresh affects data freshness
     

  • Basic performance considerations

  Students already know:  

Imagine you need answer from large book

You photocopy the entire book.

It’s right there on your desk.
You can flip pages instantly.
You can highlight, annotate, rearrange.

 But the book changes tomorrow.

Your copy doesn’t.

 Now Imagine you don’t copy the book.

 Instead, you call the library every time you need a page.

You always get the latest data, because it stays in the original system.

But:

  • Sometimes the system is busy

  • Sometimes the query takes time

  • Performance depends on the source 

 Now You don’t read the book at all.

You just ask questions.

 But you can’t rewrite the book.

A librarian has already
studied it deeply.
They’ve summarized everything.
Defined the rules.

Fast Answer

If the data is the same:

 Why would Power BI give you three completely different ways to access it?

Because how you access data changes speed, control, and trust.

          These are Import Mode, DirectQuery, and Live Connection.        

The connection mode defines performance, freshness, and freedom.

 Power BI is flexible because no single mode fits all scenarios

        Each mode is a trade-off        

 

  • How each mode works technically  

  • What you gain

  • What you lose

  • When to use each

The core section explains:

 Power BI supports three primary modes:

Each mode balances:

  • Speed

  • Freshness

  • Feature availability

  • Governance

Overview of Power BI Connection Modes

Import Mode

  • Data is copied into Power BI’s in-memory engine

  • Stored in a compressed, columnar format

  • ​Power BI queries this local data, not the source

 Once imported, all reports and visuals use the    copied data, not the original source system.

How Import Mode Works

Data is extracted from the source

Transformed using Power Query

Loaded into Power BI dataset

Reports query
in-memory data

Extremely fast performance

Best user experience for interactivity

Full Power BI feature support

Full DAX functionality

Extremely fast performance

Best user experience for
interactivity  

Full Power BI feature support

Full DAX functionality

Data becomes stale between refreshes

Requires scheduled refresh

Dataset size limits apply

Not suitable for real-time needs

Best Use Cases for Import Mode

Mostly used in all business intelligence scenarios

DirectQuery

User interacts with a visual

Results are returned to the report

Query runs on the source database

Power BI generates a query

How Direct Query Works

  • Data remains in the source system

  • Power BI does not store the data

  • Queries are sent at interaction time

Data remains in source system
Power bi does not stores the data

Always up-to-date data

No dataset size limitations in Power BI

No data duplication

Performance depends on:

  • Database optimization

  • Network latency

Limited DAX and transformation support

Heavy usage can overload source systems

Best Use Cases for DirectQuery

Operational dashboards

Financial systems

Very large datasets

Near real-time reporting

DirectQuery sends queries to the source database in real time and returns results instantly to the Power BI report when users interact with visuals.

Live Connection

Power BI connects to an external semantic model

How Live Connection Works

Data modeling happens outside Power BI Desktop

Measures, relationships, and security are predefined

Power BI acts only as a visualization layer

SQL Server Analysis Services

Azure Analysis Services

Existing Power BI datasets

Consistent metrics across teams

High performance

Centralized business logic

Strong governance

Requires mature BI infrastructure

Limited flexibility for analysts

No data modeling in Power BI Desktop

Best Use Cases for Live Connection

Enterprise BI
Large, centralized BI
models managed by
a dedicated team

 Shared Corporate Metrics 
Single semantic model
used across
many reports

 Highly Governed Environments 
Strict security, version
control, and centralized
data governance

Comparison of Connection Modes

 Choosing the Right Connection Mode

  • Choose Import for performance and flexibility
  • Choose DirectQuery for real-time or large data
  • Choose Live Connection for enterprise governance

Summary

4

The connection mode shapes the entire Power BI experience

3

Live Connection ensures centralized, governed analytics

2

DirectQuery provides live access with performance trade-offs

1

Import Mode is fastest and most flexible

Quiz

Which mode queries the source at interaction time

A. Import Mode

B. DirectQuery

C. Live Connection

D. All of the above

Which mode queries the source at interaction time

A. Import Mode

B. DirectQuery

C. Live Connection

D. All of the above

Quiz-Answer

Exploring DirectQuery and Live Connection

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Exploring DirectQuery and Live Connection

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