List:General Discussion« Previous MessageNext Message »
From:Martijn Tonies Date:March 15 2006 7:42am
Subject:Re: Accountability with MySQL
View as plain text  

> At 7:48 pm -0500 14/3/06, Rhino wrote:
> >>Ah, so now things become clear, a NULL actually can mean
> >>two things? So much for clarity then...
> >
> >Come on; that's not fair. "Unknown" and "not applicable" are more like
different senses of the same thing, not two opposite things.
>
>
> IIRC (but please don't ask for a reference) it has been suggested that
there should be two different types of NULL (value unknown & not applicable)
for just this reason.
>

Yep. "unknown" and "n/a" are two different things and SQL happens
to "support" them by NULLs. This is confusing at times and more
difficult to handle at least...

The problems with NULLs are numerous. Don't say they aren't, cause
they are. In several SQL functions, NULLs make a difference and
they will bite you every now and then. Especially for "new" people,
which is a clear signal they are confusing.

> I suppose what it boils down to is that although the two main reasons one
might use NULL are *not* the same thing, the outcome (the absence of a
value) *is* the same.
>
> So you're both right. Sort of.
> :-)

;-)

Martijn Tonies
Upscene Productions
http://www.upscene.com

Thread
Accountability with MySQLBruno B B Magalháes14 Mar
  • Re: Accountability with MySQLMartijn Tonies14 Mar
    • Re: Accountability with MySQLBruno B B Magalháes14 Mar
  • Re: Accountability with MySQLSGreen14 Mar
    • Re: Accountability with MySQLMartijn Tonies14 Mar
    • Re: Accountability with MySQLRhino14 Mar
    • Re: Accountability with MySQLMartijn Tonies14 Mar
    • Re: Accountability with MySQLRhino15 Mar
      • Re: Accountability with MySQLJames Harvard15 Mar
    • Re: Accountability with MySQLMartijn Tonies15 Mar
    • Re: Accountability with MySQLMartijn Tonies15 Mar
    • Re: Accountability with MySQLRhino15 Mar
    • Re: Accountability with MySQLMartijn Tonies15 Mar
      • Re: Accountability with MySQLStephen Cook16 Mar
    • Re: Accountability with MySQLRhino15 Mar
      • Re: Accountability with MySQLJames Harvard16 Mar
    • Re: Accountability with MySQLMartijn Tonies16 Mar
      • Re: Accountability with MySQLMark Leith16 Mar
    • Re: Accountability with MySQLMartijn Tonies16 Mar
      • Re: Accountability with MySQLJames Harvard16 Mar
      • Re: Accountability with MySQLAlec.Cawley16 Mar
        • Re: Accountability with MySQLMartijn Tonies16 Mar
          • Re: Accountability with MySQLAlec.Cawley16 Mar
          • Re: Accountability with MySQLJames Harvard16 Mar
          • RE: Accountability with MySQLGordon16 Mar
            • On MySQL Views (Re: Accountability with MySQL)Martijn Tonies16 Mar
    • Re: Accountability with MySQLMartijn Tonies16 Mar
    • Coalesce (was: Re: Accountability with MySQL)Martijn Tonies16 Mar
    • True Propositions (was Re: Accountability with MySQL)Martijn Tonies16 Mar
  • Re: Accountability with MySQLMartijn Tonies14 Mar
    • Re: Accountability with MySQLSGreen14 Mar
      • Re: Accountability with MySQLMartijn Tonies14 Mar
  • Re: Accountability with MySQLRhino14 Mar
  • Re: Accountability with MySQLRhino14 Mar
Re: Accountability with MySQLBruno B B Magalháes14 Mar
  • Re: Accountability with MySQLRhino15 Mar
Re: Accountability with MySQLMartijn Tonies16 Mar
Re: Accountability with MySQLMartijn Tonies16 Mar