Applying M transformations with DirectQuery models

• The M transformation functions supported in DirectQuery are limited by compatibility with the source system. The Query Editor will advise when a transformation is not supported in DirectQuery mode per Figure 32.

• Given this limitation and the additional complexity the M-based transforms would add to the solution, it's recommended to embed all the necessary logic and transforms in the source relational layer.
• Ideally, the base tables in the source database themselves would reflect these needs. As a secondary option, the layer of views used to support the DirectQuery Model can be modified as well to incorporate new or additional logic.
• If the database objects themselves cannot be revised, the Value.Native() M function can be used to directly pass the SQL statement from Power BI Desktop to the source database as per Figure 29.