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A data engineer runs a statement every day to copy the previous day's sales into the table transactions. Each day's sales are in their own file in the location "/transactions/raw".
Today, the data engineer runs the following command to complete this task:

After running the command today, the data engineer notices that the number of records in table transactions has not changed.
Which of the following describes why the statement might not have copied any new records into the table?

• A. The PARQUET file format does not support COPY INTO.
• B. The names of the files to be copied were not included with the FILES keyword.
• C. The COPY INTO statement requires the table to be refreshed to view the copied rows.
• D. The format of the files to be copied were not included with the FORMAT_OPTIONS keyword.
• E. The previous day's file has already been copied into the table.

A data engineer needs to enforce row-level security on main.secure.events(region STRING, event_id STRING). Members of the account group all_regions need to see all rows. All other users need to see only rows where region = 'EU'. Which SQL sequence satisfies the requirement?

• A.
  
• B.
  
• C.
  
• D.
  

A data engineering team needs to ingest historical CSV files from a cloud storage location that already contains 50,000 existing files. They also expect new files to arrive continuously going forward. The team wants to use Auto Loader to incrementally process both existing files and new arrivals efficiently. Which Auto Loader mode should the team configure for this use case?

• A. Use file notification mode only after all existing files have been processed, as it cannot efficiently handle large volumes of pre-existing files.
• B. Use file notification mode because it scales efficiently for both large numbers of existing files and continuous new arrivals by using cloud storage events rather than repeatedly listing directories.
• C. Use directory listing mode because it provides better performance for the initial processing of
  50,000 existing files through optimized incremental listing capabilities.
• D. Use directory listing mode initially to process the 50,000 existing files, then reconfigure the stream to use file notification mode for ongoing ingestion of new arrivals.

A data engineer is onboarding a new bronze ingestion pipeline in Databricks with Unity Catalog.
The team wants Databricks to handle storage layout, apply platform optimizations over time, and simplify lifecycle management so that when a table is dropped, its underlying data is also cleaned up according to Databricks-managed retention policies.
Which table type should the data engineer create for these ingestion tables?

• A. Foreign tables federated from an external catalog to delegate optimization to the source system.
• B. Temporary views over files to avoid table-level governance and lifecycle coupling.
• C. External tables with a LOCATION pointing to an external volume for full control of file layout.
• D. Managed tables so that Unity Catalog manages both metadata and underlying data lifecycle.

A data engineer wants to read only a subset of columns from a Delta table to reduce memory usage and improve performance. Which Spark DataFrame operation should be used?

• A. filter
• B. groupBy
• C. select
• D. orderBy