/*+XXXXX*/的具体含义？

流云飞渡

9I中新增的这个/*+XXXXX*/的具体含义是什么？
例：SQL>;select /*+CACHE*/ename from scott.emp;

tinywind

这是hint,提供了执行sql时更细微的控制,这个语句是让结果保留在cache中

hint不是9i中加入，很早就有，现在oracle已经不推荐使用hint了

流云飞渡

能给个链接或更详细的解释吗？

tinywind

去查oracle的文档，我以前在8的文档中看到过

流云飞渡

查过了，没查到，所以才发的帖子

mydeer

为什么不推荐hint？？

sshd

In general oracle optimizer will control how to execute a sql. Sometimes a user may choose to bypass that and tell oracle to execute the sql in the way he suggested. Thus he can use hint /*+ ... */ to achive that.
Note if any thing is wrong in the hint oracle just ingore it and you will not get any error.