- A
Ensure that single-field indexes exist for both 'status' and 'timestamp'
Single-field indexes are automatically created, but for composite queries, the composite index is essential.
- B
Enable automatic composite index creation in Firestore settings
Why wrong: Automatic composite indexes are not a feature; they must be manually created.
- C
Create an index exemption for the 'timestamp' field
Why wrong: Index exemptions are for disabling indexes on arrays/maps, not needed here.
- D
Create a composite index on the 'status' and 'timestamp' fields
Composite index is needed for queries with multiple fields.
- E
Use gcloud alpha firestore indexes composite create to define the index
gcloud can be used to create composite indexes.
Question 441 of 1,000
PCDOE Manage Database Solutions Practice Question
This PCDOE practice question tests your understanding of manage database solutions. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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 developer is building an application that uses Firestore (in Datastore mode). The application needs to query data across two properties: 'status' and 'timestamp', with an equality filter on 'status' and a range filter on 'timestamp'. Which three steps are required to support this query efficiently? (Choose THREE.)
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
✓
Ensure that single-field indexes exist for both 'status' and 'timestamp'
Option A is correct because Firestore (in Datastore mode) requires single-field indexes to be defined for each property used in a query, even when a composite index is also present. Without a single-field index on 'status' and 'timestamp', the query engine cannot efficiently evaluate the equality and range filters, leading to full table scans or query failures.
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.
- ✓
Ensure that single-field indexes exist for both 'status' and 'timestamp'
Why this is correct
Single-field indexes are automatically created, but for composite queries, the composite index is essential.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Enable automatic composite index creation in Firestore settings
Why it's wrong here
Automatic composite indexes are not a feature; they must be manually created.
- ✗
Create an index exemption for the 'timestamp' field
Why it's wrong here
Index exemptions are for disabling indexes on arrays/maps, not needed here.
- ✓
Create a composite index on the 'status' and 'timestamp' fields
Why this is correct
Composite index is needed for queries with multiple fields.
Related concept
Read the scenario before looking for a memorised answer.
- ✓
Use gcloud alpha firestore indexes composite create to define the index
Why this is correct
gcloud can be used to create composite indexes.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the misconception that automatic index creation (like in Firestore Native mode) applies to Datastore mode, or that index exemptions can substitute for proper composite index design.
Detailed technical explanation
How to think about this question
Under the hood, Firestore (Datastore mode) uses a distributed storage system where indexes are B-tree structures. For a query with an equality filter on 'status' and a range filter on 'timestamp', the query planner first uses the composite index (status, timestamp) to narrow results by status, then scans the timestamp range within that partition. Without the composite index, the query would require a merge of two separate index scans, which is not supported and would fail. In real-world scenarios, such as querying for 'active' orders within the last 24 hours, the composite index ensures sub-second response times even with millions of documents.
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.
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.
- →
Manage Database Solutions — study guide chapter
Learn the concepts, then practise the questions
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FAQ
Questions learners often ask
What does this PCDOE question test?
Manage Database Solutions — This question tests Manage Database Solutions — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Ensure that single-field indexes exist for both 'status' and 'timestamp' — Option A is correct because Firestore (in Datastore mode) requires single-field indexes to be defined for each property used in a query, even when a composite index is also present. Without a single-field index on 'status' and 'timestamp', the query engine cannot efficiently evaluate the equality and range filters, leading to full table scans or query failures.
What should I do if I get this PCDOE 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
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Last reviewed: Jul 4, 2026
This PCDOE 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 PCDOE exam.
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