Important Concepts of DirectQuery

[Anonymous]

Before opting to go with a DirectQuery connection, it is important to get a better understanding of it.

• Better scalability since extremely large datasets can be used for building reports and the size limitation is only for the data source itself.
• No need for data refresh since its coming as a real time data.
• Pre-Built models in some data sources can be used instantly.
• DirectQuery reports always work on the current data and the hard work is carried out where it should be done on the server side.
• In case of re-query of data, server hits can be avoided to a great extent since the application would reuse already existing data
• It is possible to later switch from DirectQuery to Import mode if needed.
• All tables must come from a single database that is a single data source only. There is simply no way of combining data from multiple sources
• Few limitations are placed on the DAX expressions that are allowed in measures
• Some limitations on Data modelling such as auto-detect relationships between tables and relationships are limited to a single direction
• Built-in Date hierarchy is not available

[Icey]

Hi @Anonymous ,

Thanks for your sharing. Great summary.

But there is one thing to note: 

• All tables must come from a single database, unless using composite models.

• All tables must come from a single database that is a single data source only. There is simply no way of combining data from multiple sources

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Best Regards,

Icey

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[Anonymous]

Thank you for the information. Much appreciated!

[edhans]

I've created direct query models across data in different databases. You have to create views in a single database pointing to the other databases, then connect to those views.

There are some limitations with visuals too in Direct Query.

Good writeup!

[JCM_iTalent]

@Anonymous If you are interest in writing a blog for us, please click on the Message Admins to the right of the Community Blog.

Thank you.

[amitchandak]

@Anonymous , Thaks for sharing. Best way write a blog on the power bi community.

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