Skip to main content
The features described in this article are in public preview and may change.
Transformations can query Microsoft Fabric OneLake Lakehouse Delta tables without staging a full copy in CDF RAW. You register an external data source, then read it in SQL with ext_onelake. Transformation results are still written to CDF destinations such as data models. Fabric remains the system of record for the source tables. Each run reads the current Delta table state over ABFSS (Azure Blob File System Secure).

​
What this path does

​
How it works

  1. Register a Fabric OneLake integration as an external data source (credentials plus workspace and lakehouse IDs).
  2. Reference a Delta table in transformation SQL with ext_onelake(...).
  3. Shape the data with Spark SQL.
  4. Write the result to a CDF destination such as a data model.
You register the external data source with the Transformations API. Runtime stays in Transformations.

​
Requirements

  • Fabric Lakehouse Delta tables under Tables/ (optional single schema folder).
  • Microsoft Entra ID service principal with at least Contributor on the Fabric workspace or lakehouse (Viewer is not enough for OneLake API access).
  • CDF capabilities for external data sources and Transformations.

​
Next steps

Set up an external data source

Register Fabric OneLake credentials and location with the API.

Read Fabric OneLake data

Query with ext_onelake and write to a CDF destination.
For API schemas, see Transformation external data sources and the beta OpenAPI tag.
Last modified on August 25, 2026