Perhaps, the only time you will have to choose a type of connection is when you connect to a data source that supports multiple connection types. If all you connect to is MS Excel, you might not witness an option because it only supports one type of connection.
Why is this a tough decision?
If Power BI only had one way to connect to data sources, then everything was easy. You never needed to find the right method for yourself. However, Power BI supports three different ways of connecting to data:
- Direct Query
- Live Connection
- Import Data (Scheduled Refresh).
Many of them think that Direct Query and Live Connection are the same, but no they are different. Each of them has its own advantages and disadvantages. Depending on the scenario that you are going to implement Power BI for, you might choose one that best suits your scenario.
Changing from one method to another method can be a time-consuming task after a while in the implementation process. So choosing the right method from the beginning would be best and will not waste your time later.
Which method is performing best and fast?
Import Data is a fast and best possible option. Data is loaded into the memory of the server and all queries will be resolved immediately.
Live Connection is the next option in this list, especially if SSAS Tabular or Power BI Service is used because these two are in-memory technologies and perform faster than multi-dimensional.
Direct Query is the slowest type of connection. You have to consider the performance tuning of your data source.
The winner for performing best and fast is Import Data.
Which method is more flexible?
With Import Data you get the full functionality of Power BI. Full Power Query transformations, and DAX measures as well as visualizations.
Direct Query and Live Connection both are the next in this list because each of them gives you something. Direct Query will give you few Power Query options. Live Connection will give you Report Level Measures.
The winner for flexibility is again Import Data.
Which method is more scalable?
The import Data method has a size limitation of 1GB per model. Without using Power BI Premium, this method is not so much Scalable.
With Direct Query and Live Connection, you get better scalability. Data sources support a large amount of data.
The winner for Scalability is Live Connection and Direct Query.
For most companies who need more reporting and analytical prowess than that offered by Excel, Power BI is the next level in BI. With it, businesses can amass, analyze, and envisage data from the length and breadth of the company, providing them better insight into their operations and performance, and helping them to make well- informed decisions based on real-time data.
If you seek to do the same, do