讨教关于V$SQL_BIND_DATA与cursor_sharing

laobu

讨教关于V$SQL_BIND_DATA，下面摘自reference
For each distinct bind variable in each cursor owned by the session querying this view, this view describes:
    Actual bind data, if the bind variable is user defined
    The underlying literal, if the CURSOR_SHARING parameter is set to FORCE and the bind variable is system generated. (System-generated binds have a value of 256 in the SHARED_FLAG2 column.)
这里的“The underlying literal”，如何理解呢？
谢谢

laobu

也就是说，这里只是强调一下与“Actual bind data”有区别
谢谢

Maclean Liu(刘相兵

underlying literal=> 潜在的自由变量    指实际没有绑定变量 使用硬编码+ 自由变量，如

select * from tab where t1= [literal]

当 CURSOR_SHARING=FORCE

optimizer 会将该查询转换为

select * from tab where t1= :SYS_BIND_1

这样的 强制绑定形式