What is the user Derivation Rule? How to create derivation rule in CO-PA?
SAP Boss replied
Derivation lets you find values for certain characteristics automatically based on the known values of other characteristics, where these characteristics are logically dependent on one another.
When an operating concern is generated, the system produces a standard derivation strategy containing all known dependencies between characteristics. You can display these by choosing "View -> Display all steps".
You can change the standard derivation strategy by
Creating additional steps
Adjusting changeable standard steps to suit your situation or deleting them
Changing the step sequence
Proceed as follows:
Creating a step
1. Select the step that is to precede the new step you wish to add. Choose "Create step".
2. Choose the desired type of derivation step from those available.
3. Enter a text as well as source and target fields for the derivation step. By using the arrow button, you can determine field characteristics for the source and target fields.
4. If the derivation step should only be executed unter certain conditions, such as only for specific characteristic values, make the entry under "Condition".
5. You determine step characteristics under "Characteristics". For example, you determine whether an error message should be generated if no target value can be calculated.
If you use the derivation step type "Derivation rule", some additional entry options are available:
Under "Maintain rule values", you enter which values in the target fields should be placed in which characteristic values of the source fields.
Under "Characteristics", you can make additional entries which, for example, make it possible to enter a validity date for the step.
<a href="http://help.sap.com/erp2005_ehp_02/helpdata/en/7a/4c48c64a0111d1894c0000e829fbbd/frameset.htm">Charateristic derivation</a>