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Re: indexing a column with only 2 or 3 values

From: DA Morgan <damorgan_at_psoug.org>
Date: Sat, 04 Aug 2007 09:20:43 -0700
Message-ID: <1186244441.239493@bubbleator.drizzle.com>


Helma wrote:

>> Ideally you might arrange the design such that the small number of
>> rows you typically want to identify are flagged with a 'Y' (say) and
>> the rest left null. Then a standard btree index on that column would
>> be compact and efficient.

>
> Redesign? What's wrong with my suggestion to create an index on only
> the Y value's?
>
> H.

Nothing ... your original idea is superior in several respects. NULLs are not information ... they are the lack of it.

-- 
Daniel A. Morgan
University of Washington
damorgan_at_x.washington.edu (replace x with u to respond)
Puget Sound Oracle Users Group
www.psoug.org
Received on Sat Aug 04 2007 - 11:20:43 CDT

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