Referring to the UML DataType description on IBM's Help Center:
A data type is similar to a class; however, instances of data type are identified only by their value. If two data types have the same value, the instances are considered identical.
So this means, that you can't seperate these objects of this DataType by their identifier, because they don't have any. Only the current value is used to compare instances. Like int
-instances in Java for example.
I hope I could help...