[nycphp-talk] Need help understanding NULL
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Sun Aug 30 10:12:05 EDT 2009
Hans Zaunere wrote:
> NULL is just a type - a type that can only ever be one thing - NULL
I think I get that part now: The moment it has a known value, even if
that value is '' or zero, then it's no longer NULL (at least in the
world according to MySQL).
> NULL comes from pointers, largely where there can be null references
> or pointers. It's an address that doesn't point anywhere, but is
> some way pointed to and acknowledged, thus it's not purely
> non-existent (yes, we could argue for years on the subtle meanings of
> NULL, void, undefined, etc. :)
Hans, you're going to make my head explode. LOL
> As always, there's only one real resource these days:
>
> http://en.wikipedia.org/wiki/Null
Oddly, while I go to Wikipedia probably a dozen times a day for answers,
it never occurred to me to look up NULL there. Go figure.
> To me, pragmatically, NULL really only comes down to one thing - it's
> a special type that always has a single value. Different languages
> and environments then utilize this type differently, and add their
> own meanings. Thus you need to read the different environment's docs
> to learn how NULL is treated specifically in that environment, and
> how it affects getting things down in that environment. There is no
> "global" real meaning of NULL - it's language specific.
Noted.
> Other than that NULL is meaningless - it's NULL :)
Bev :)
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