Type for class designator column when using STI?

[Jeff de Vries]

Does it matter what data type the "class designator column" is when 
using STI?  Are there any expectations on the values in the class 
designator column? For example, can you use an integer column, with 1 
meaning Employee, 2 meaning Manager, 3 meaning Customer, etc?  Does 
Cayenne know what class to instantiate by looking at the qualifier 
expression?

Thanks,
Jeff de Vries