Databasen - NULL dates
Nigel Rantor
wiggly at wiggly.org
Wed Oct 18 13:44:16 BST 2006
Jurgen Pletinckx wrote:
> | NULL is the unknown value. Your dates are unknown. Sounds like a
> | perfect match to me. I'd be interested in hearing the other point of
>
> | view.
>
> This may just represent fuzzy thinking on my part, but...
>
> I can see where I would be interested in the difference between
> as-yet-unknown (will be filled in during one of the next rounds
> of data entry) and unknowable (won't ever be filled in, barring
> paradigm shift or policy change).
>
> NULL and VERY NULL?
>
> Or is this standard question nr 27, and did I just flunk?
Well, let's say we have:
1) As yet unknown, will possibly be known in the future (date of death,
employee resgination)
2) Unknowable (end of the universe)
If something falls into category 2 then why model it at all? It is a
constant.
If we're going to start talking about things that depend on company
policy then you cannot try to model all things that a policy states we
cannot know because the list would be endless.
n
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