From: "Mark Leith" > 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
Got that one ;) The book I quoted is from Date, btw, and I enjoy reading it ... > 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. Well, the question still is if you should store "unknown" at all ;) Not according to Date: you should store what is known. See the remarks about the "true propositions", from which relational databases are derived (but you probably know that). >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. I guess I can agree with that one. > This argurment will, however, carry on between "academia" and "the real > world" for at least the next 4000 years. :) Until it gets replaced by a better model, but I don't expect that anytime soon ;-) Martijn Tonies Database Workbench - development tool for MySQL, and more! Upscene Productions http://www.upscene.com My thoughts: http://blog.upscene.com/martijn/ Database development questions? Check the forum! http://www.databasedevelopmentforum.com -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
