Mastering Microsoft Power BI

Import mode

An import mode dataset can include multiple data sources, such as SQL Server, Oracle, and an Excel file. Since a snapshot of the source data is loaded into the Power BI cloud service, in addition to its in-memory columnar compressed structure, query performance is usually good for most scenarios. Another important advantage of import mode datasets is the ability to implement data transformations without negatively impacting query performance. Unlike DirectQuery datasets, the operations of data source SQL views and the M queries of Import datasets are executed during the scheduled data refresh process. The Query Design per dataset mode section of Chapter 2, Connecting to Sources and Transforming Data with M, discusses this issue ...