Can a bitmap index be used for index-only access?

From: Tolkin, Steve <Steve.Tolkin_at_FMR.COM>
Date: Sat, 8 Nov 2008 18:48:37 -0500

Can a bitmap index be used for index-only access?

Suppose there is a single bitmap index defined on two columns A and B in table T.
Can that bitmap index alone be used for certain queries, without needing to read any blocks from the base table?
For example these two queries:
Select B from T where A ='a1'
Select A from T where B ='b2'

(An ordinary B-tree index on columns A and B, in that order, supports index only access on the first query above, but not the second.)

Where, if anywhere, is this described in the Oracle documentation?


Steve Tolkin
Vice President
PWI Strategy and Architecture
Fidelity Investments
400 Puritan Way M3B
Marlborough MA 01752

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-- Received on Sat Nov 08 2008 - 17:48:37 CST

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