- A
The CREATE INDEX statement will block reads on the table during index creation
Why wrong: Spanner index creation is non-blocking.
- B
Indexes can only be created as unique indexes
Why wrong: Indexes can be non-unique as well.
- C
The ALTER TABLE statement to add a column is non-blocking and can be executed using gcloud spanner databases ddl update
Spanner DDL changes are online and non-blocking.
- D
Both ALTER TABLE and CREATE INDEX can be submitted together in a single DDL batch
Multiple DDL statements can be batched in Spanner.
- E
To create an index, you must first export and re-import the data
Why wrong: No need to export/import; index creation is online.
Question 769 of 1,000
PCDOE Manage Database Solutions Practice Question
This PCDOE practice question tests your understanding of manage database solutions. 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 team manages a Cloud Spanner database and needs to perform a schema change to add a new column to an existing table and create a secondary index. They want to avoid downtime and ensure the changes are applied without blocking reads or writes. Which two statements are correct about making these changes in Spanner? (Choose TWO.)
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
✓
The ALTER TABLE statement to add a column is non-blocking and can be executed using gcloud spanner databases ddl update
In Cloud Spanner, both ALTER TABLE (to add columns) and CREATE INDEX are online, non-blocking operations. They can be run via DDL statements in the gcloud CLI or console. Indexes can be created as UNIQUE to enforce uniqueness.
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.
- ✗
The CREATE INDEX statement will block reads on the table during index creation
Why it's wrong here
Spanner index creation is non-blocking.
- ✗
Indexes can only be created as unique indexes
Why it's wrong here
Indexes can be non-unique as well.
- ✓
The ALTER TABLE statement to add a column is non-blocking and can be executed using gcloud spanner databases ddl update
Why this is correct
Spanner DDL changes are online and non-blocking.
Related concept
Read the scenario before looking for a memorised answer.
- ✓
Both ALTER TABLE and CREATE INDEX can be submitted together in a single DDL batch
Why this is correct
Multiple DDL statements can be batched in Spanner.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
To create an index, you must first export and re-import the data
Why it's wrong here
No need to export/import; index creation is online.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
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.
- Use explanations to understand the rule behind the answer.
TExam Day Tips
- Underline the problem statement mentally.
- 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 PCDOE exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
- →
Manage Database Solutions — study guide chapter
Learn the concepts, then practise the questions
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Manage Database Solutions practice 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: The ALTER TABLE statement to add a column is non-blocking and can be executed using gcloud spanner databases ddl update — In Cloud Spanner, both ALTER TABLE (to add columns) and CREATE INDEX are online, non-blocking operations. They can be run via DDL statements in the gcloud CLI or console. Indexes can be created as UNIQUE to enforce uniqueness.
What should I do if I get this PCDOE question wrong?
Identify which PCDOE exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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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