Summary

In this chapter, we saw how the two storage modes in Power BI work. Import mode datasets create a local in-memory cache of the data in Power BI. DirectQuery mode datasets pass queries through to external data sources. Generally, Import mode is the fastest because it is local to Power BI, in-memory, a column-based database, and compresses data to make working with it more efficient. However, DirectQuery mode provides a way to always have the latest data returned from the source and avoid managing data refreshes. It also allows you to access very large datasets that are far beyond the capacity available in Power BI Premium. In this way, there is a trade-off between these two modes. However, Power BI also provides composite models that blend Import and DirectQuery for very good performance gains.

You have also learned the role of on-premises gateways for enterprises to allow Power BI to connect securely with on-premises data sources. Gateways host Power BI's mashup engine...