This FC0-U61 practice question tests your understanding of database fundamentals. 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 database administrator is troubleshooting a slow query on a large table. Which index type would improve performance for an exact match search on a single column?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
B-tree index
A B-tree index is the correct choice for an exact match search on a single column because it organizes data in a balanced tree structure that allows O(log n) lookups, making it highly efficient for equality searches. In a large table, the B-tree index reduces the number of disk I/O operations by quickly navigating to the leaf node containing the exact key value.
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.
✗
Clustered index
Why it's wrong here
Clustered indexes sort and store data physically, which may not always improve performance for exact matches.
✓
B-tree index
Why this is correct
B-tree indexes are ideal for exact match and range queries, providing fast lookup.
Related concept
Read the scenario before looking for a memorised answer.
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Bitmap index
Why it's wrong here
Bitmap indexes are efficient for columns with few distinct values, not for high-cardinality columns.
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Hash index
Why it's wrong here
Hash indexes are fast for exact matches but do not support range queries.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse clustered indexes with performance gains for all query types, not realizing that a clustered index primarily optimizes data retrieval order and can slow down writes, while a B-tree index is the standard choice for exact match searches in most relational databases.
Detailed technical explanation
How to think about this question
B-tree indexes maintain sorted key values with pointers to the corresponding rows, and their balanced nature ensures that the height of the tree grows logarithmically with the number of entries, keeping search time consistent even for millions of rows. In practice, databases like MySQL InnoDB use B+ tree variants where leaf nodes contain the actual data or a pointer to it, and internal nodes act as a sparse index to guide the search. A subtle behavior is that B-tree indexes also support prefix lookups and range scans, making them versatile beyond exact matches.
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 practitioner preparing for the FC0-U61 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
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.
Database Fundamentals — This question tests Database Fundamentals — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: B-tree index — A B-tree index is the correct choice for an exact match search on a single column because it organizes data in a balanced tree structure that allows O(log n) lookups, making it highly efficient for equality searches. In a large table, the B-tree index reduces the number of disk I/O operations by quickly navigating to the leaf node containing the exact key value.
What should I do if I get this FC0-U61 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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Question Discussion
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