说明：  《Oracle9i 的查询优化》描述了Oracle 的查询优化程序，它是数据库的关键组件，能让Oracle 的用户获得极佳的执行性能。Oracle 的查询优化技术在功能上无与伦比，本文详细讨论了查询优化的所有重要领域。
(" Oracle9i Query Optimization" describes Oracle' s query optimizer, which is a key component of the database, allowing users access to Oracle' s implementation of excellent performance. Oracle' s query optimizer technology is unmatched in capabilities, this paper discusses in detail all the important areas of query optimization.)