1. Which query optimization technique involves breaking down a complex query into smaller, simpler subqueries?
Explanation: Query decomposition involves breaking down a complex query into smaller, simpler subqueries to optimize query execution.
Report for correction2. What is the primary purpose of indexing columns that are frequently used in WHERE clauses of SQL queries?
Explanation: The primary purpose of indexing columns that are frequently used in WHERE clauses of SQL queries is to speed up data retrieval by allowing for efficient query filtering.
Report for correction3. What is the main goal of query optimization in a database?
Explanation: The main goal of query optimization in a database is to improve query performance by selecting the most efficient query execution plan.
Report for correction4. In query optimization, what is "cost-based optimization"?
Explanation: Cost-based optimization in query optimization involves optimizing queries based on estimated query execution costs to choose the most efficient query plan.
Report for correction5. What is the primary disadvantage of using too many indexes in a database?
Explanation: The primary disadvantage of using too many indexes in a database is slower query performance due to increased overhead during data modification and maintenance.
Report for correction6. Which type of index is most suitable for columns with Boolean (true/false) values?
Explanation: Bitmap indexes are most suitable for columns with Boolean (true/false) values as they efficiently represent such data.
Report for correction7. In query optimization, what is the purpose of "predicate pushdown"?
Explanation: Predicate pushdown in query optimization involves pushing query filters or conditions closer to the data source, reducing the amount of data to be processed.
Report for correction8. What is the primary purpose of a bitmap index in a database?
Explanation: The primary purpose of a bitmap index in a database is to speed up data retrieval for specific columns by using bitmaps to represent data values.
Report for correction9. What is an "access path" in the context of query optimization?
Explanation: An access path in query optimization refers to the order in which data is accessed to satisfy a query efficiently.
Report for correction10. Which query optimization technique aims to execute multiple parts of a query in parallel to improve performance?
Explanation: Query parallelization aims to execute multiple parts of a query in parallel to improve query performance.
Report for correction11. In a database, what is the purpose of a composite index?
Explanation: A composite index in a database combines multiple columns into a single index, allowing for efficient querying on combinations of those columns.
Report for correction12. Which type of index is used to enforce the uniqueness of values in a column?
Explanation: A Unique Index is used to enforce the uniqueness of values in a column, preventing duplicate entries.
Report for correction13. What is the primary advantage of using indexing in a database?
Explanation: The primary advantage of using indexing in a database is faster data retrieval, as it allows for efficient data access.
Report for correction14. What is the primary purpose of indexing in a database?
Explanation: The primary purpose of indexing in a database is to optimize query performance by allowing for faster data retrieval.
Report for correction15. What is an "execution plan" in the context of query optimization?
Explanation: An execution plan in query optimization is a plan for executing SQL statements that includes the order of operations and access methods to retrieve data efficiently.
Report for correction16. Which index type is well-suited for columns with high cardinality and where range queries are common?
Explanation: B-Tree indexes are well-suited for columns with high cardinality and are efficient for range queries.
Report for correction17. What is query optimization in a database management system?
Explanation: Query optimization in a database management system is the process of rewriting SQL queries to improve their performance.
Report for correction18. Which type of index is often used for text-based searches, such as searching for words within a document?
Explanation: Full-Text Indexes are often used for text-based searches, enabling efficient searching for words or phrases within documents.
Report for correction19. What is the purpose of a non-clustered index in a database?
Explanation: The purpose of a non-clustered index is to speed up data retrieval for specific columns without affecting the physical order of data rows.
Report for correction20. Which query optimization technique rearranges the execution order of operators in a query plan to improve performance?
Explanation: Query optimization involves rearranging the execution order of operators in a query plan to improve query performance.
Report for correction21. What is the main benefit of using a clustered index in a database?
Explanation: The main benefit of using a clustered index in a database is faster data retrieval as it determines the physical order of data rows.
Report for correction22. In database indexing, what is the term for the column or set of columns used as the search key for the index?
Explanation: In database indexing, the column or set of columns used as the search key for the index is referred to as key columns.
Report for correction23. Which type of index is most suitable for columns with low cardinality, such as gender or status?
Explanation: Bitmap indexes are most suitable for columns with low cardinality, where there are a limited number of distinct values.
Report for correction24. What is a "covering index" in the context of query optimization?
Explanation: A covering index is an index that covers all columns in a table, making it unnecessary to access the table for query processing.
Report for correction25. Which data structure is commonly used for creating indexes in databases?
Explanation: B-Trees are commonly used data structures for creating indexes in databases due to their balanced nature and efficient search capabilities.
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