Alf Pedersen

Recent Blog Comments By Alf Pedersen

• Alf Pedersen On NULL Value Usage In Database Design

  Posted on Nov 21, 2007 at 1:03 PM

  Hi all, Thank you for not flaming me :-) It happens so ofte that discussions on the subject escalates. A friendly argument is nicer. David, I'll answer you with a few questions. Answer them, and I'll take on your task ;-) 1. How many middle names do you want? I have one, my father had 2. My mothe... read more »

• Alf Pedersen On NULL Value Usage In Database Design

  Posted on Nov 21, 2007 at 3:46 AM

  Ken, Chris Date once said, "Theory is practical!" And it sure is. Your table end_date_unk should not contain a record: you are still employed. "My method handles an unknown date with a concept built to handle unknowns..." Fine. Teach your concept to the programmers coming in after you leave, s... read more »

• Alf Pedersen On NULL Value Usage In Database Design

  Posted on Nov 20, 2007 at 8:58 PM

  Hi, I could do that, but it would be just like delivering you the answers without presenting you with the questions. Besides, I am very busy right now checking a database model for a friend (and myself). But to help you on your way, I have found the following links very valuable: Please read all ... read more »

• Alf Pedersen On NULL Value Usage In Database Design

  Posted on Nov 20, 2007 at 5:51 PM

  Ken, You say: "I totally agree with that in mathematical terms. The problem I have here is that you cannot relate this to the way sum works..." So SUM is not a mathematical function? Actually, does it work at all, or is it tricking us? You see, this is not easy, and I don't blame you, but i DO b... read more »

• Alf Pedersen On NULL Value Usage In Database Design

  Posted on Nov 20, 2007 at 3:41 PM

  Hi Ken & all, No offense taken at all! Just a pleasure talking to you. And yes, Ben runs a good blog: credits given. The problem you state with SUM is relevant; very much so indeed! The same goes for other aggregates. But: WHERE lies the problem? Actually, Ken, you answered it yourself: 3+5+x =... read more »

• Alf Pedersen On NULL Value Usage In Database Design

  Posted on Nov 20, 2007 at 2:10 PM

  Ben, I told you that you'd put the heat on me! :-) But you really do have a nice comment to Ken, and I will join you there. I really like the style of your blog. Now, let's get straight on with it: Ken, I may do a lot of arm-waiving to get my point across. Never did see it that way, but you may be... read more »