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what's the theory behind using a NULL column

 
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jctgf
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Joined: 05 Nov 2006
Posts: 89
Topics: 36
PostPosted: Wed Mar 11, 2009 6:40 pm    Post subject: what's the theory behind using a NULL column Reply with quote
hi there,

i wonder if there's any advantage in using NULL columns, please?

is there any gain in performance or any saving in disk space?

in my case, the columns will rarely have a null value and the table is huge
(4 billion records)

thanks.
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kolusu
Site Admin
Site Admin


Joined: 26 Nov 2002
Posts: 12375
Topics: 75
Location: San Jose
PostPosted: Wed Mar 11, 2009 7:25 pm    Post subject: Reply with quote
jctgf,

It depends on the usage and how your data is. Check this link which explains as to why a null value is efficient when compared to having a default value

http://publibz.boulder.ibm.com/cgi-bin/bookmgr_OS390/BOOKS/DSNITH11/2.4.2.3.3?

Read this also

http://publibz.boulder.ibm.com/cgi-bin/bookmgr_OS390/BOOKS/DSNITH11/2.4.2.3.1?

Kolusu
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