You can use virtual indexes together with the PLAN function to explore the performance impact of an index, without the often time-consuming and resource-consuming effects of creating a real index.

• 可以结合使用虚拟索引和PLAN函数以充分利用索引在性能方面的提高,从而避免创建真实索引这一通常又耗时又消耗资源的过程。