Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
A company uses Azure SQL Database for an e-commerce application. The Orders table has millions of rows. Queries that filter on CustomerID and order by OrderDate are slow. The table currently has a clustered index on OrderID (the primary key). Which index strategy will best improve these queries?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Distractor review
A. Create a nonclustered index on OrderDate only.
This index would help with ordering by OrderDate, but the query first needs to filter on CustomerID. Without an index on CustomerID, a full scan or inefficient lookup is needed.
B
Distractor review
B. Create a filtered index on CustomerID where Status = 'Active'.
A filtered index is limited to rows that meet a specific condition. If queries filter by CustomerID regardless of Status, this index may be incomplete and not used.
C
Best answer
C. Create a nonclustered index on (CustomerID, OrderDate).
This composite index allows efficient seek on CustomerID and then an ordered scan of OrderDate, covering both the filter and the sort without additional operations.
D
Distractor review
D. Create a nonclustered index on OrderID and OrderDate.
This index does not include CustomerID, so it cannot be used to filter on CustomerID efficiently. It would not help the query.
Common exam trap
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.
Technical deep dive
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.
Related practice questions
Related DP-900 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
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FAQ
Questions learners often ask
What does this DP-900 question test?
Read the scenario before looking for a memorised answer.
What is the correct answer to this question?
The correct answer is: C. Create a nonclustered index on (CustomerID, OrderDate). — The queries filter by a specific CustomerID and then order the results by OrderDate. A nonclustered index on (CustomerID, OrderDate) allows the database to quickly locate rows matching the CustomerID (using the leading column) and then retrieve them in the required order without a sort. An index on OrderDate alone would help with ordering but not filtering. A filtered index on CustomerID with a condition (e.g., Status='Active') is too narrow and may not cover all queries. An index on (OrderID, OrderDate) does not help because the filter is on CustomerID, not OrderID.
What should I do if I get this DP-900 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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