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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 9 months, 4 weeks 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 5 months, 1 week ago
Selected Answer: A
Option A https://cloud.google.com/bigquery/docs/best-practices-performance-nested
upvoted 2 times
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hanoverquay
7 months, 2 weeks ago
Selected Answer: A
optional A
upvoted 1 times
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JyoGCP
8 months, 1 week ago
Selected Answer: A
Option A
upvoted 1 times
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Matt_108
9 months, 2 weeks ago
Selected Answer: A
Option A
upvoted 1 times
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scaenruy
10 months 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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