Re: No Nulls? (was: Warehouse design: snowflake vs star schemas)

From: <JApplewhite_at_austin.isd.tenet.edu>
Date: Mon, 14 Oct 2002 11:58:59 -0800
Message-ID: <F001.004E8638.20021014115859@fatcity.com>

Rich,

I piqued my own curiosity and looked at "Database Programming and Design On-Line". Below is a link to a lengthy response (1995) by Date and others to Tom Johnston's article defending MVL (Multi-Valued Logic). Plenty to chew on.

http://www.dbpd.com/vault/dateresp.htm

Jack C. Applewhite
Database Administrator
Austin Independent School District
Austin, Texas
512.414.9715
JApplewhite_at_austin.isd.tenet.edu

                                                                                           
                    Jack                                                                   
                    Applewhite           To:     ORACLE-L_at_fatcity.com                      
                                         cc:                                               
                    10/14/2002           Subject:     Re: No Nulls? (was: Warehouse        
                    01:32 PM             design: snowflake vs star schemas)(Document link: 
                                         Jack Applewhite)                                  
                                                                                           

Rich,

Several years ago in the old "Database Programming and Design" magazine (a really useful publication, IMHO - too bad it's gone), C. J. Date and another database guru (I can't remember his name) carried on a debate that lasted several months about the "badness" (Date) vs "goodness" (the other guy) of Three Valued Logic in general and Nulls in particular. Date even wrote an article showing how to design a database with all Not Null columns.

The issues are many, but, for me, the bottom line is that it's easier to live with the "evils" of Nulls - including the extra coding you have to do to make sure they're handled appropriately for each SQL statement - than to do all the upfront work required to eliminate them.

Theoretically speaking, I think Date is totally correct. Practically speaking, I'm too lazy to implement his ideas. ;-)

Jack C. Applewhite
Database Administrator
Austin Independent School District
Austin, Texas
512.414.9715
JApplewhite_at_austin.isd.tenet.edu

                                                                                             
                    "Jesse, Rich"                                                            
                    <Rich.Jesse_at_qti       To:     Multiple recipients of list ORACLE-L       
                    world.com>             <ORACLE-L_at_fatcity.com>                            
                    Sent by:              cc:                                                
                    root_at_fatcity.co       Subject:     No Nulls? (was: Warehouse design:     
                    m                      snowflake vs star schemas)                        
                                                                                             
                                                                                             
                    10/14/2002                                                               
                    12:33 PM                                                                 
                    Please respond                                                           
                    to ORACLE-L                                                              
                                                                                             
                                                                                             

On the link below is this quote from C.J.Date:

"I don't want you to think that my SQL solution to your problem means I advocate the use of nulls. Nulls are a disaster."

Of course, he doesn't expound upon it (probably not a need except for dummies like me). Anyone care to comment? (On the quote, not on my dumminess...)

Rich

Rich Jesse                           System/Database Administrator
Rich.Jesse_at_qtiworld.com              Quad/Tech International, Sussex, WI

USA
> -----Original Message-----
> From: Robson, Peter [mailto:pgro_at_bgs.ac.uk]
> Sent: Monday, October 14, 2002 4:59 AM
> To: Multiple recipients of list ORACLE-L
> Subject: RE: Warehouse design: snowflake vs star schemas
>
>
> Just for the record (and perhaps to confirm that there are
> always two sides
> to a story). Readers may like to see the article Chris Date
> wrote to Ralph
> Kemball on the subject of business rules and integrity constraints:
>
> http://www.dbdebunk.com/kimball1.htm

--
Author: Jesse, Rich
  INET: Rich.Jesse_at_qtiworld.com






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Received on Mon Oct 14 2002 - 14:58:59 CDT