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From:Mark Leith Date:March 16 2006 10:39am
Subject:Re: Accountability with MySQL
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Martijn Tonies wrote:

>We're arguing about whether or not your database design
>(as stored on disk) should contain NULLs.
>
>IMO: no, or at least as few as possible.
>  
>
I believe the answer really is - *it depends*.

You are both right, really. Martijn, yes, according to academia and 
proper database design, you should not really be using NULLs, (Rhino, 
see the writings of Chris Date and Fabian Pascal somewhere like 
www.dbdebunk.com, www.thethirdmanifesto.com etc.). Here's a good one:

http://www.dbdebunk.citymax.com/page/page/1396241.htm

Of course, you're still going to pay $10-$15 for this..

However, what is good for academia is *not* always good for the real 
world. Why store "Unknown" in a column for a table that could store 
millions, or billions, of rows, when you could simply allow a NULL (and 
save a *bunch* of disk space across your schemas) in the real world. If 
you can allow for the use of the NULL in the application, and *not* try 
to interpret it 5 ways from Sunday, then, in my honest opinion, a NULL 
would be acceptable.

Short answer, as long as you do it without trying to get your 
application to handle them in many different ways, I don't see a great 
problem (when weighing them against extra costs, in both space and 
speed). If you can get away with not using NULL as well, then great.

This argurment will, however, carry on between "academia" and "the real 
world" for at least the next 4000 years. :)

Best regards

Mark

-- 
Mark Leith, Support Engineer
MySQL AB, Worcester, England, www.mysql.com
Are you MySQL certified?  www.mysql.com/certification

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