Re: datawarehouse explain plan question

From: Jonathan Lewis <jonathan_at_jlcomp.demon.co.uk>
Date: Tue, 18 May 1999 20:39:52 +0100
Message-ID: <927057540.8124.0.nnrp-01.9e984b29@news.demon.co.uk>

This is just a detail of terminology

A range scan is an index scan that is capable of returning several rows, even if the scan is performed on a unique index.

The only way to get a UNIQUE SCAN is to supply all columns of the index in order to guarantee a single row will be returned.

Jonathan Lewis
Yet another Oracle-related web site: www.jlcomp.demon.co.uk

My understanding was that as long as you referenced columns in a = left-wise fashion

on a composite index, you could still get a UNIQUE scan. Received on Tue May 18 1999 - 14:39:52 CDT