关于BW出口变量

关于BW Query的出口变量，网上好多资料

I_STEP = 1  可以初始化变量值

I_STEP = 2 也可以给变量赋值，但是变量必须不是”用户已准备输入“（ready for input）

I_STEP = 3 用来检查变量值，可以返回消息

百度可以返回好多结果，可是我想通过出口跟用户说两句话，这个功能试了两天也没成功，只好暂时搁置了。

主要想说，I_STEP = 3 不要写在"CASE i_vnam"语句里面,不然跳不进来，写在CASE之外，就能够执行了。后来又继续找了找资料，这么说的，应该是只执行一次的意思，不知理解是否正确了。

I_Step = 3

is not called by each variable but only once. When it is called all the variable content transferred for validation purpose. So you can check period from is smaller than or equal to period_to provided the two different value not from interval, but from  two different variable as input. Triggering  an exception (RAISE) causes the variable screen to appear once more. Afterwards, I_STEP=2 is also called 。

原文在这里https://archive.sap.com/discussions/message/333258