When to use Dataflow vs Dataset?

HI PowerrrBrrr 

I don't think I could be considered an "expert" but I am using both Datasets and Dataflows, and as I'm teaching this topic today, I can share these slides I use ....

Why Use Dataflows ?

• Not a replacement for a data warehouse, but useful when:
  –There is no data warehouse in your organisation
  –The data warehouse does not contain the data you need

• Reduces overall data refresh time:
  –Extracting once and re-using multiple times means you only pay the performance price for the initial slow extract once
  –Reading data from a dataflow is fast, probably much faster than extracting data from the original source

• Reduces load on/number of calls to source system
  –Eg when refresh could affect the performance of a line-of-business database
  –Eg when there is a limit on the number of calls to an API

• More consistency between datasets – less chance that different users will make different decisions when preparing data
• Share complex M queries that some users would not be able to write
• Share tables that have no source, eg Date dimensions generated in M

These come from the excellent Matthew Roche's blog Dataflows – BI Polar (ssbipolar.com) Matthew is pretty much the expert on Dataflows and his blog is well worth a read.

Hope this helps

Stuart