Inconsistencies in a Class Hierarchy

To ensure that values assigned to characteristics are consistent across a hierarchy, the system makes checks. The following activities can cause inconsistencies:

• Changing the allowed values

If you change the allowed values for a characteristic, so that the value assigned to an object is no longer valid, you see an inconsistency message. You must delete your change.

• Deleting an assignment

you delete an assignment in a class hierarchy, and a subordinate class no longer contains an inherited characteristic that has been used to classify objects, this causes inconsistency. You cannot delete the assignment until you have deleted values for the characteristic for classified objects.

• Deleting a characteristic from a class

If a characteristic is inherited by subordinate classes in a class hierarchy, where objects are classified with the characteristic, you can no longer delete the characteristic from the class. You can only delete the characteristic if you delete all the assigned values for the characteristic first.

• Deleting a class in a class hierarchy

If a class is part of a class hierarchy, and characteristics of the class are inherited and used to classify objects in subordinate classes, you cannot delete the class.

You assign class CL2 to class CL1, restricting the allowed values for characteristic C2 to A and B. When you classify object O1, you can only assign one of these values. If you assign value A to object O1, but change the value set for the assignment of CL2 to CL1 to B and C, the value assigned to object O1 becomes inconsistent. You see an inconsistency message, telling you that you cannot change the allowed values.

As long as object O1 has an assigned value for characteristic C2, the following restrictions apply:

• You cannot delete the assignment of CL2 to CL1

• You cannot delete characteristic C2 from class CL1

• You cannot delete class CL1