Databricks Databricks-Certified-Data-Engineer-Professional 問題集

質問 1：
The data governance team is reviewing user for deleting records for compliance with GDPR. The following logic has been implemented to propagate deleted requests from the user_lookup table to the user aggregate table.

Assuming that user_id is a unique identifying key and that all users have requested deletion have been removed from the user_lookup table, which statement describes whether successfully executing the above logic guarantees that the records to be deleted from the user_aggregates table are no longer accessible and why?
A. Yes; Delta Lake ACID guarantees provide assurance that the DELETE command successed fully and permanently purged these records.
B. No; the Delta Lake DELETE command only provides ACID guarantees when combined with the MERGE INTO command
C. No; files containing deleted records may still be accessible with time travel until a BACUM command is used to remove invalidated data files.
D. Yes; the change data feed uses foreign keys to ensure delete consistency throughout the Lakehouse.
E. No; the change data feed only tracks inserts and updates not deleted records.
正解：C
解説: (Topexam メンバーにのみ表示されます)

質問 2：
A junior data engineer is working to implement logic for a Lakehouse table named silver_device_recordings. The source data contains 100 unique fields in a highly nested JSON structure.
The silver_device_recordings table will be used downstream to power several production monitoring dashboards and a production model. At present, 45 of the 100 fields are being used in at least one of these applications.
The data engineer is trying to determine the best approach for dealing with schema declaration given the highly-nested structure of the data and the numerous fields.
Which of the following accurately presents information about Delta Lake and Databricks that may impact their decision-making process?
A. Schema inference and evolution on .Databricks ensure that inferred types will always accurately match the data types used by downstream systems.
B. Because Databricks will infer schema using types that allow all observed data to be processed, setting types manually provides greater assurance of data quality enforcement.
C. Because Delta Lake uses Parquet for data storage, data types can be easily evolved by just modifying file footer information in place.
D. The Tungsten encoding used by Databricks is optimized for storing string data; newly-added native support for querying JSON strings means that string types are always most efficient.
E. Human labor in writing code is the largest cost associated with data engineering workloads; as such, automating table declaration logic should be a priority in all migration workloads.
正解：B
解説: (Topexam メンバーにのみ表示されます)

質問 3：
A data ingestion task requires a one-TB JSON dataset to be written out to Parquet with a target Get Latest & Actual Certified-Data-Engineer-Professional Exam's Question and Answers from part- file size of 512 MB. Because Parquet is being used instead of Delta Lake, built-in file-sizing features such as Auto-Optimize & Auto-Compaction cannot be used.
Which strategy will yield the best performance without shuffling data?
A. Set spark.sql.shuffle.partitions to 2,048 partitions (1TB*1024*1024/512), ingest the data, execute the narrow transformations, optimize the data by sorting it (which automatically repartitions the data), and then write to parquet.
B. Set spark.sql.files.maxPartitionBytes to 512 MB, ingest the data, execute the narrow transformations, and then write to parquet.
C. Set spark.sql.adaptive.advisoryPartitionSizeInBytes to 512 MB bytes, ingest the data, execute the narrow transformations, coalesce to 2,048 partitions (1TB*1024*1024/512), and then write to parquet.
D. Ingest the data, execute the narrow transformations, repartition to 2,048 partitions (1TB*
1024*1024/512), and then write to parquet.
E. Set spark.sql.shuffle.partitions to 512, ingest the data, execute the narrow transformations, and then write to parquet.
正解：A
解説: (Topexam メンバーにのみ表示されます)

質問 4：
A Databricks SQL dashboard has been configured to monitor the total number of records present in a collection of Delta Lake tables using the following query pattern:
SELECT COUNT (*) FROM table
Which of the following describes how results are generated each time the dashboard is updated?
A. The total count of records is calculated from the Delta transaction logs
B. The total count of records is calculated from the Hive metastore
C. The total count of records is calculated from the parquet file metadata
D. The total count of rows is calculated by scanning all data files
E. The total count of rows will be returned from cached results unless REFRESH is run
正解：A
解説: (Topexam メンバーにのみ表示されます)

質問 5：
The following table consists of items found in user carts within an e-commerce website.
Get Latest & Actual Certified-Data-Engineer-Professional Exam's Question and Answers from

The following MERGE statement is used to update this table using an updates view, with schema evaluation enabled on this table.

How would the following update be handled?
A. The new restored field is added to the target schema, and dynamically read as NULL for existing unmatched records.
B. The update is moved to separate ''restored'' column because it is missing a column expected in the target schema.
C. The update throws an error because changes to existing columns in the target schema are not supported.
D. The new nested field is added to the target schema, and files underlying existing records are updated to include NULL values for the new field.
正解：D
解説: (Topexam メンバーにのみ表示されます)

質問 6：
The security team is exploring whether or not the Databricks secrets module can be leveraged for connecting to an external database.
After testing the code with all Python variables being defined with strings, they upload the password to the secrets module and configure the correct permissions for the currently active Get Latest & Actual Certified-Data-Engineer-Professional Exam's Question and Answers from user. They then modify their code to the following (leaving all other variables unchanged).

Which statement describes what will happen when the above code is executed?
A. The connection to the external table will fail; the string "redacted" will be printed.
B. The connection to the external table will succeed; the string "redacted" will be printed.
C. The connection to the external table will succeed; the string value of password will be printed in plain text.
D. An interactive input box will appear in the notebook; if the right password is provided, the connection will succeed and the encoded password will be saved to DBFS.
E. An interactive input box will appear in the notebook; if the right password is provided, the connection will succeed and the password will be printed in plain text.
正解：B
解説: (Topexam メンバーにのみ表示されます)

質問 7：
Which statement describes Delta Lake optimized writes?
A. Optimized writes logical partitions instead of directory partitions partition boundaries are only Get Latest & Actual Certified-Data-Engineer-Professional Exam's Question and Answers from represented in metadata fewer small files are written.
B. Before a job cluster terminates, OPTIMIZE is executed on all tables modified during the most recent job.
C. An asynchronous job runs after the write completes to detect if files could be further compacted; yes, an OPTIMIZE job is executed toward a default of 1 GB.
D. A shuffle occurs prior to writing to try to group data together resulting in fewer files instead of each executor writing multiple files based on directory partitions.
正解：D
解説: (Topexam メンバーにのみ表示されます)