Question 1
Domain 4: Data Sharing and FederationWhich Unity Catalog object do you create to expose an external PostgreSQL database for read-only querying with Lakehouse Federation?
Correct answer: C
Explanation
Lakehouse Federation is used to "configure Lakehouse Federation with proper governance across supported source systems," and Unity Catalog exposes external data sources through a foreign catalog. A foreign catalog lets you query the external PostgreSQL database in read-only mode without ingesting the data into Databricks.
Why each option is right or wrong
A. An external location
External locations define cloud storage paths, not database federation objects.
B. A share
Shares are for Delta Sharing data distribution, not querying an external PostgreSQL source.
C. A foreign catalog
Unity Catalog exposes external systems for federated access through a foreign catalog, which is the object created when you register an external data source under Lakehouse Federation. For PostgreSQL, this gives read-only SQL access to the remote database without copying data into Databricks, matching the federation model described in the Databricks docs for external source systems.
D. A volume
Volumes store files in Unity Catalog; they do not expose external databases for federation.