Indexing and Query Optimization

Test your ability to improve database performance and efficiency.

1. Which index type is most commonly used for range queries in relational databases?
2. Which of the following are benefits of using indexes? (Select all that apply)
3. A covering index includes all columns needed by a query, so the database doesn't need to access the table data.
4. What term describes the process of rearranging index pages to reduce fragmentation?
5. Which SQL clause is often used to suggest the optimizer use a specific index?
6. Which factors affect query performance? (Select all that apply)
7. Hash indexes are suitable for range queries (e.g., WHERE age > 30).
8. What acronym refers to the structure showing steps a database takes to execute a query?
9. Which index type is best for columns with low cardinality (few distinct values)?
10. Which are types of query optimizers? (Select all that apply)
11. Normalization always improves query performance.
12. What term refers to the selectivity of an index (percentage of rows a query returns)?
13. Which join operation benefits most from indexes on join columns?
14. Which are 'bad practices' for query optimization? (Select all that apply)
15. Hash indexes provide faster lookups than B-tree indexes for equality queries.
16. What is the process of rewriting a query to improve performance without changing results?
17. Which factor does a cost-based optimizer primarily use to choose execution plans?
18. Which are common index types? (Select all that apply)
19. Adding more indexes to a table always improves query performance.
20. What acronym is used for the optimization approach that relies on predefined rules rather than statistics?
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