IBM DB2 面试题与答案
问题 16. What is a foreign key in DB2?
A foreign key is a column or set of columns in a table that refers to the primary key of another table. It establishes a link between the two tables.
问题 17. How can you improve the performance of a DB2 query?
Performance can be improved by creating indexes, optimizing SQL queries, updating statistics, and using proper join and filter conditions.
问题 18. What is a DB2 package?
A DB2 package is a compiled set of SQL statements and procedures stored in the database. It can be executed by database applications.
问题 19. Explain the purpose of the REORG utility in DB2.
The REORG utility is used to reorganize the physical storage of tables and indexes, optimizing space usage and improving query performance.
问题 20. What is a DB2 index and how does it improve query performance?
An index is a data structure that provides a quick and efficient way to look up and access data in a table. It improves query performance by reducing the number of rows that need to be scanned.
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