- A
Cloud SQL cross-database query
Why wrong: Cloud SQL does not support querying Cloud Storage directly.
- B
BigQuery Omni
Why wrong: BigQuery Omni is for querying data in other clouds (AWS, Azure), not for Cloud SQL or Cloud Storage.
- C
BigQuery federated queries using external tables
Federated queries allow querying Cloud SQL (via JDBC) and Cloud Storage (via external tables) directly from BigQuery.
- D
BigQuery Data Transfer Service
Why wrong: Data Transfer Service is for scheduled imports, not federated queries.
Question 706 of 980
PCD Practice Question: Manage a Solution that Can Span Multiple Database Systems
This PCD practice question tests your understanding of manage a solution that can span multiple database systems. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
An organisation needs to run SQL queries across data stored in Cloud SQL MySQL and Cloud Storage (CSV files) without moving the data. They want to use BigQuery as the query engine. Which feature should they use?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
BigQuery federated queries using external tables
BigQuery federated queries using external tables allow you to query data stored in Cloud SQL and Cloud Storage (CSV files) directly from BigQuery without moving the data. This is achieved by creating an external table definition in BigQuery that references the source, enabling SQL queries across both sources in a single query using BigQuery's query engine.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Cloud SQL cross-database query
Why it's wrong here
Cloud SQL does not support querying Cloud Storage directly.
- ✗
BigQuery Omni
Why it's wrong here
BigQuery Omni is for querying data in other clouds (AWS, Azure), not for Cloud SQL or Cloud Storage.
- ✓
BigQuery federated queries using external tables
Why this is correct
Federated queries allow querying Cloud SQL (via JDBC) and Cloud Storage (via external tables) directly from BigQuery.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
BigQuery Data Transfer Service
Why it's wrong here
Data Transfer Service is for scheduled imports, not federated queries.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the distinction between moving data (Data Transfer Service) and querying in place (federated queries), and candidates may confuse BigQuery Omni with cross-cloud capabilities when the scenario is purely within GCP.
Detailed technical explanation
How to think about this question
BigQuery federated queries use external data sources via the EXTERNAL_QUERY function for Cloud SQL or external table definitions for Cloud Storage, leveraging the BigQuery Storage API and the Cloud SQL Auth Proxy for secure connections. Under the hood, BigQuery pushes down query predicates to Cloud SQL to optimize performance, while for CSV files in Cloud Storage, it reads data on the fly using the BigQuery Storage Read API. A real-world scenario is a retail company joining real-time inventory data from Cloud SQL with historical sales data in Cloud Storage CSV files for a unified analytics dashboard.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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Manage a Solution that Can Span Multiple Database Systems — study guide chapter
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FAQ
Questions learners often ask
What does this PCD question test?
Manage a Solution that Can Span Multiple Database Systems — This question tests Manage a Solution that Can Span Multiple Database Systems — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: BigQuery federated queries using external tables — BigQuery federated queries using external tables allow you to query data stored in Cloud SQL and Cloud Storage (CSV files) directly from BigQuery without moving the data. This is achieved by creating an external table definition in BigQuery that references the source, enabling SQL queries across both sources in a single query using BigQuery's query engine.
What should I do if I get this PCD question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Last reviewed: Jul 4, 2026
This PCD practice question is part of Courseiva's free Google Cloud certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the PCD exam.
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