Databricks Certified Data Engineer Professional — Question 65

A junior data engineer is migrating a workload from a relational database system to the Databricks Lakehouse. The source system uses a star schema, leveraging foreign key constraints and multi-table inserts to validate records on write.

Which consideration will impact the decisions made by the engineer while migrating this workload?

Answer options

• A. Databricks only allows foreign key constraints on hashed identifiers, which avoid collisions in highly-parallel writes.
• B. Databricks supports Spark SQL and JDBC; all logic can be directly migrated from the source system without refactoring.
• C. Committing to multiple tables simultaneously requires taking out multiple table locks and can lead to a state of deadlock.
• D. All Delta Lake transactions are ACID compliant against a single table, and Databricks does not enforce foreign key constraints.
• E. Foreign keys must reference a primary key field; multi-table inserts must leverage Delta Lake’s upsert functionality.

Correct answer: D

Explanation

The correct answer is D because, in Databricks, while Delta Lake transactions are ACID compliant, they do not enforce foreign key constraints, which is a significant difference from traditional relational databases. Options A and C are incorrect as they misrepresent how Databricks handles foreign key constraints and locking mechanisms. Option B is misleading since migrating logic may require refactoring, and option E incorrectly states requirements for foreign keys and multi-table inserts.