1
vote
1answer
115 views

Alternatives to NULL for missing data [duplicate]

I am using PostgreSQL and trying to write value constraints. Is it possible to record missing data as distinct from NULL values in a numeric field without using an arbitrary numeric value? For many ...
11
votes
4answers
732 views

Does NULL have a type?

Various sources (eg Wikipedia, PSOUG) state that Oracle's null does not have a type. Is this true? What about other RDBMSs?