- A
Pub/Sub
Datastream can publish to Pub/Sub, which can then be streamed into BigQuery via subscriptions, though direct streaming is also possible.
- B
Dataflow
Why wrong: Dataflow is serverless but requires pipeline development; it's not as turnkey as Datastream for this use case.
- C
Datastream
Datastream provides serverless CDC from Oracle to BigQuery with minimal configuration.
- D
Cloud Scheduler
Why wrong: Cloud Scheduler is for scheduled jobs, not streaming.
- E
Cloud Functions
Why wrong: Cloud Functions is not designed for high-throughput CDC replication.
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.
A company needs to synchronize sales transactions from an on-premises Oracle database to BigQuery for near-real-time analytics. They want a serverless solution that requires minimal operational overhead. Which TWO services should they consider?
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
Pub/Sub
Pub/Sub is correct because it provides a serverless, highly scalable ingestion service that can receive change data capture (CDC) events from an on-premises Oracle database via a connector like Debezium or Oracle GoldenGate, and stream them into BigQuery for near-real-time analytics without managing servers. Datastream is correct because it is a serverless CDC service specifically designed to replicate data from sources like Oracle directly to BigQuery, handling schema mapping and minimal operational overhead.
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.
- ✓
Pub/Sub
Why this is correct
Datastream can publish to Pub/Sub, which can then be streamed into BigQuery via subscriptions, though direct streaming is also possible.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Dataflow
Why it's wrong here
Dataflow is serverless but requires pipeline development; it's not as turnkey as Datastream for this use case.
- ✓
Datastream
Why this is correct
Datastream provides serverless CDC from Oracle to BigQuery with minimal configuration.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Cloud Scheduler
Why it's wrong here
Cloud Scheduler is for scheduled jobs, not streaming.
- ✗
Cloud Functions
Why it's wrong here
Cloud Functions is not designed for high-throughput CDC replication.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Google Cloud exams often test the distinction between services that are serverless ingestion sources (Pub/Sub, Datastream) versus processing or compute services (Dataflow, Cloud Functions), leading candidates to pick Dataflow because it is associated with streaming, despite it not being the minimal-overhead solution for simple CDC ingestion.
Detailed technical explanation
How to think about this question
Datastream uses log-based CDC to capture changes from Oracle redo logs, minimizing impact on the source database, and can stream directly to BigQuery via a staging location in Cloud Storage. Pub/Sub can integrate with Oracle GoldenGate or Debezium to publish change events, but requires additional configuration for exactly-once semantics and ordering, which Datastream handles natively for BigQuery. In real-world scenarios, combining both allows for decoupled ingestion (Pub/Sub) and direct replication (Datastream) depending on downstream needs.
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 cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
Quick reference
Cloud Service Model Comparison
| Model | You Manage | Provider Manages | Examples |
|---|---|---|---|
| IaaS | OS, runtime, apps, data | Hardware, hypervisor, networking | EC2, Azure VMs, GCP Compute Engine |
| PaaS | Apps and data | OS, runtime, middleware, hardware | Elastic Beanstalk, Azure App Service |
| SaaS | Data and settings only | Everything else | Microsoft 365, Salesforce, Workday |
| FaaS / Serverless | Function code only | Infra, scaling, runtime | Lambda, Azure Functions, Cloud Run |
| CaaS | Containers and apps | Kubernetes, OS, hardware | EKS, AKS, GKE |
What to study next
Got this wrong? Here's your next step.
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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: Pub/Sub — Pub/Sub is correct because it provides a serverless, highly scalable ingestion service that can receive change data capture (CDC) events from an on-premises Oracle database via a connector like Debezium or Oracle GoldenGate, and stream them into BigQuery for near-real-time analytics without managing servers. Datastream is correct because it is a serverless CDC service specifically designed to replicate data from sources like Oracle directly to BigQuery, handling schema mapping and minimal operational overhead.
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 →
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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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