Certified Data Engineer Professional Exam

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Question 142

The data engineering team maintains the following code:

Assuming that this code produces logically correct results and the data in the source tables has been de-duplicated and validated, which statement describes what will occur when this code is executed?

A batch job will update the enriched_itemized_orders_by_account table, replacing only those rows that have different values than the current version of the table, using accountID as the primary key.

The enriched_itemized_orders_by_account table will be overwritten using the current valid version of data in each of the three tables referenced in the join logic.

No computation will occur until enriched_itemized_orders_by_account is queried; upon query materialization, results will be calculated using the current valid version of data in each of the three tables referenced in the join logic.

An incremental job will detect if new rows have been written to any of the source tables; if new rows are detected, all results will be recalculated and used to overwrite the enriched_itemized_orders_by_account table.

Correct Answer: B

The code uses the .write.mode('overwrite') method when writing the final DataFrame to the table 'enriched_itemized_orders_by_account'. This method will overwrite the existing table with the new data, thus ensuring the table is completely updated with the latest data from the three source tables ('accounts', 'orders', 'items'). Therefore, the enriched_itemized_orders_by_account table will be overwritten using the current valid version of data in each of the three tables referenced in the join logic.

Discussion

hpkrOption: B

B is correct