Backward chaining with 'Whenever Used' option

Hi All,

Developer help says:
As a best practice, select Whenever used when the expression involves values from properties on multiple pages.

I tried but couldn't understand anything from this.

Can anyone please elaborate how this feature can be used?

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June 28, 2011 - 1:37am


I have read about the declare expressions. I have gone through the PDN webinars about declarative processing also.

But still it doesn't help much to understand how whenever used option can be used with multiple pages?

July 1, 2011 - 2:25am

Whenever used option uses backward chaining. Lets say you have a decision table A = B*C+D. Here assume B,C,D comes from different pages.

If you use "whenever used" option, only when A is accessed, the expression is computed. This saves time. The computation does not happen when B or C or D changes. It will happen only when A is accessed. This will improve performance.

Hope you got it !!