You can use the WHEN function in a component rule to test for the validity of one object based on another object.

WHEN evaluates a condition. Then, based on that evaluation, evaluates another condition and returns "true" or "false".

WHEN ( single-condition-expression , single-condition-expression [ , single-condition-expression ] )
WHEN ( condition1 , condition2 [ , condition3 ] )
"True" or "false"

The following statements summarize how the WHEN function works:

  • Returns "true" if condition1 and condition2 both evaluate to "true".
  • Returns "true" if condition1 evaluates to "false" and there is no condition3 or if condition1 evaluates to "false" and condition3 evaluates to "true".
  • Returns "false" if condition1 evaluates to "true" and condition2 evaluates to "false".
  • Returns "false" if both condition1 and condition3 evaluate to "false".

Evaluation of the three arguments:

Condition 1 Condition 2 Condition 3 WHEN returns:
True True True
False True
False True True
True False False
False False False


  • WHEN (ABSENT(CatalogueField), ABSENT (QuantityField))

    Returns "true" when CatalogueField and QuantityField are both absent

  • WHEN (PRESENT(ShipDate), PRESENT(InStock), PRESENT(BackOrderDate ))

    Returns "false" when ShipDate and BackOrderDate are both absent