> But (in at least some situations) is not appropriate to record that you
know that you don't have a value?
Sure it would. It it's needed.
But the answer doesn't have to be a NULL. Remember
the example about recording the fact that a student did
not make a test for whatever reason?
It was then said you could store "null" for the test score.
I then replied that that was a bit backward IMO, cause
you're using the "test scores" table to store that a student
did not take a test, which is wrong, given that each row
in a table should mean exactly the same thing (theory
knocking at the door once again) and that makes a design
> I think the words of Donald Rumsfeld are appropriate here:
> "There are known knowns. These are things we know that we know. There are
known unknowns. That is to say, there are things that we know we don't know.
But there are also unknown unknowns. There are things we don't know we don't
I think we'll have a hard time storing Donalds "knows" and
"unknowns" in a database... :-)
> At 12:02 pm +0100 16/3/06, Martijn Tonies wrote:
> >Well, the question still is if you should store "unknown" at all ;)
> >Not according to Date: you should store what is known.
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