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From Iris Eiron <irisei...@gmail.com>
Subject Crearting an INDEX on null values
Date Thu, 13 Aug 2009 23:24:54 GMT
Hello,

I have this table with a cloumn A whose value may be null. I'd like to
create an index on A, so that I can efficiently access rows using WHERE A=?
statements. I would never of course need to access rows whose A value is
null.

For better performance, can I tell Derby not to index rows whose A value is
null? If so, how? Should I create at all an index on a column which is not
defined as NOT NULL? Will it improve performance?

Thanks,
- Iris

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