This view demonstrates attributes that assume a substitute value if the attribute is not set. In a context (table on the left), objects can be created (in a grid on the right) that have attributes with a substitute value.

The substitute value is fed from another attribute, which can also be entered in the same object for test purposes. Technically, an attribute with a substitute value consists of three attributes (the attribute with a substitute value, a storage attribute in which an explicitly entered value is stored and an attribute that supplies the substitute value). The storage attribute is usually hidden and is only used for internal storage of explicitly entered values. Specialist logic can access the storage attribute to check whether an explicit value has been entered or whether the attribute with replacement value uses its replacement value. When accessing the attribute with substitute value, it is not possible to determine whether it is an explicitly entered value or the substitute value. Accessing the attribute simply returns a value, either the explicitly entered value or the substitute value if no value has been explicitly entered.