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Home -> Community -> Mailing Lists -> Oracle-L -> RE: No Nulls? (was: Warehouse design: snowflake vs star schemas)
But from a practical, operational standpoint, NULLable columns can cause
problems, the least of which is lack of index-ability (for lack of a better
term) when issuing queries containing NOT NULLs and the like. Of course one
might say that one should know the database one is issuing a query against,
but when you have ad-hoc users in a DW who are querying based on a meta-data
catalog somewhere you can't expect them to always ask the question, is this
a nullable column. :-)
RF
Robert G. Freeman - Oracle OCP
Oracle Database Architect
CSX Midtier Database Administration
Author of several Oracle books you can find on Amazon.com!
Londo Mollari: Ah, arrogance and stupidity all in the same package. How efficient of you.
-----Original Message-----
[mailto:JApplewhite_at_austin.isd.tenet.edu]
Sent: Monday, October 14, 2002 3:34 PM
To: Multiple recipients of list ORACLE-L
schemas)
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, WIUSA
> >
-- Author: Jesse, Rich INET: Rich.Jesse_at_qtiworld.com -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: INET: JApplewhite_at_austin.isd.tenet.edu Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Freeman, Robert INET: Robert_Freeman_at_csx.com Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).Received on Mon Oct 14 2002 - 17:03:44 CDT
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