Why does Oracle 9i treat an empty string as NULL?

Question

I know that it does consider \' \' as NULL, but that doesn\'t do much to tell me why this is the case. As I understand the SQL specifications

Answer 1

I suspect this makes a lot more sense if you think of Oracle the way earlier developers probably did -- as a glorified backend for a data entry system. Every field in the database corresponded to a field in a form that a data entry operator saw on his screen. If the operator didn't type anything into a field, whether that's "birthdate" or "address" then the data for that field is "unknown". There's no way for an operator to indicate that someone's address is really an empty string, and that doesn't really make much sense anyways.