- A
Enable single-field indexes for both fields; Firestore will automatically use them.
Why wrong: Single-field indexes are insufficient for multi-field queries.
- B
Rewrite the query using 'IN' clauses to avoid the need for a composite index.
Why wrong: Composite indexes may still be needed depending on the query.
- C
Create a composite index on status and date in the Firebase Console or using gcloud.
Firestore in Native mode requires a composite index for queries that filter on multiple fields or combine filters with ordering. The index must include both fields.
- D
Change the database to Datastore mode, which does not require indexes.
Why wrong: Datastore mode also requires composite indexes for similar queries.
Question 813 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 company has a Firestore database in Native mode. They need to run a query that filters on two fields (status and date) and orders by date. The query is slow and returns an error that a matching index is missing. What must the engineer do to resolve this?
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
✓
Create a composite index on status and date in the Firebase Console or using gcloud.
Option C is correct because Firestore requires a composite index on both the equality filter field (status) and the order field (date) when a query uses equality filters on one field and an order on another. Without this composite index, the query cannot be executed efficiently and returns an error. Creating the composite index via the Firebase Console or gcloud CLI resolves the issue.
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.
- ✗
Enable single-field indexes for both fields; Firestore will automatically use them.
Why it's wrong here
Single-field indexes are insufficient for multi-field queries.
- ✗
Rewrite the query using 'IN' clauses to avoid the need for a composite index.
Why it's wrong here
Composite indexes may still be needed depending on the query.
- ✓
Create a composite index on status and date in the Firebase Console or using gcloud.
Why this is correct
Firestore in Native mode requires a composite index for queries that filter on multiple fields or combine filters with ordering. The index must include both fields.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Change the database to Datastore mode, which does not require indexes.
Why it's wrong here
Datastore mode also requires composite indexes for similar queries.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the misconception that single-field indexes are automatically combined for multi-field queries, or that using 'IN' clauses bypasses indexing requirements, when in fact composite indexes are mandatory for such queries.
Trap categories for this question
Similar concept trap
Datastore mode also requires composite indexes for similar queries.
Detailed technical explanation
How to think about this question
Firestore uses a composite index to efficiently merge equality filters and ordering in a single index scan. The index definition must include the equality field(s) first, followed by the order field(s) in the specified direction. In a real-world scenario, if the query orders by date descending, the composite index must specify 'date DESC' to avoid a full scan and sort.
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.
Visual reference
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: Create a composite index on status and date in the Firebase Console or using gcloud. — Option C is correct because Firestore requires a composite index on both the equality filter field (status) and the order field (date) when a query uses equality filters on one field and an order on another. Without this composite index, the query cannot be executed efficiently and returns an error. Creating the composite index via the Firebase Console or gcloud CLI resolves the issue.
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.
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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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