Exam Professional Data Engineer topic 1 question 267 discussion

Actual exam question from Google's Professional Data Engineer

Question #: 267
Topic #: 1

[All Professional Data Engineer Questions]

You are creating a data model in BigQuery that will hold retail transaction data. Your two largest tables, sales_transaction_header and sales_transaction_line, have a tightly coupled immutable relationship. These tables are rarely modified after load and are frequently joined when queried. You need to model the sales_transaction_header and sales_transaction_line tables to improve the performance of data analytics queries. What should you do?

A. Create a sales_transaction table that holds the sales_transaction_header information as rows and the sales_transaction_line rows as nested and repeated fields.
B. Create a sales_transaction table that holds the sales_transaction_header and sales_transaction_line information as rows, duplicating the sales_transaction_header data for each line.
C. Create a sales_transaction table that stores the sales_transaction_header and sales_transaction_line data as a JSON data type.
D. Create separate sales_transaction_header and sales_transaction_line tables and, when querying, specify the sales_transaction_line first in the WHERE clause.

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Suggested Answer: A 🗳️

by scaenruy at Jan. 3, 2024, 6:27 p.m.

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raaad

Highly Voted 1 year ago

Selected Answer: A

- In BigQuery, nested and repeated fields can significantly improve performance for certain types of queries, especially joins, because the data is co-located and can be read efficiently. - - This approach is often used in data warehousing scenarios where query performance is a priority, and the data relationships are immutable and rarely modified.

upvoted 6 times

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josech

Most Recent 7 months, 3 weeks ago

Selected Answer: A

Option A https://cloud.google.com/bigquery/docs/best-practices-performance-nested

upvoted 2 times

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hanoverquay

10 months ago

Selected Answer: A

optional A

upvoted 1 times

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JyoGCP

10 months, 3 weeks ago

Selected Answer: A

Option A

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Matt_108

1 year ago

Selected Answer: A

Option A

upvoted 1 times

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scaenruy

1 year ago

Selected Answer: A

A. Create a sales_transaction table that holds the sales_transaction_header information as rows and the sales_transaction_line rows as nested and repeated fields.

upvoted 1 times

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