Databasen - NULL dates

Nigel Rantor wiggly at
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).
> 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 

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.


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