Administering Relational Databases on Microsoft Azure — Question 71

You plan to build a structured streaming solution in Azure Databricks. The solution will count new events in five-minute intervals and report only events that arrive during the interval.
The output will be sent to a Delta Lake table.
Which output mode should you use?

Answer options

• A. complete
• B. append
• C. update

Correct answer: B

Explanation

The 'append' output mode is correct because it allows for the addition of new records to the Delta Lake table without altering existing data, which fits the requirement of counting only new events in specified intervals. The 'complete' mode would overwrite the entire table with the results, while 'update' would modify existing records, neither of which is appropriate for this use case.