Subtypes can be based on an integer attribute only.
Please enable subtypes to be built on a text attribute.
Example:
I have a natural key for countries as a text string "US", "UK", "AT", ...
I have to keep a surrogate integer key corresponding with the natural key in 1:1 relationship (1 ~ "US", 2 ~ "UK", 3 ~ "AT"...) and I have to ensure data integrity among these two attributes by rather complicated mechanism. This is due only to the need to create a subtype on the country...
So, cucrrently, I have to make a complex solution for basic tasks...
Please consider this functionality. This will simplyfy the application design in many cases a lot.
