REPOST: Re: 2 overlapping indexes

Take a good look at your example.

Record 1 ABCD = X 1 Y 2
Record 2 ABCD = X 1 Y 3

I'm sorry but your ABC is the same "X1Y" in both cases. You have not reflected what was stated in the original posting.

This is more likely the worst case possible:

Record 1 ABCD = X 1 Y 2
Record 2 ABCD = X 1 Z 2

Daniel Morgan

miker wrote:

> On Fri, 25 Jan 2002 09:39:39 -0000, Norman Dunbar
> <Norman.Dunbar_at_lfs.co.uk> wrote:
>
> >I must be missing the point here :
> >
> >id A,B,C are unique then surely A,B,C,D *must* also be unique if the
> >columns are in that order.
>
> Record 1 ABCD = X 1 Y 2
> Record 2 ABCD = X 1 Y 3
>
> ABCD is unique but ABC is not. If you put a unique index on ABCD then
> you do not enforce ABC uniqueness. I think the guy wants to enforce
> unique constrant AND speed up retrieval of ABCD record.
>
> M

• WAS CANCELLED BY =======: From: "Daniel A. Morgan" <damorgan_at_exesolutions.com> Control: cancel <3C512D69.4F572E0_at_exesolutions.com> Subject: cmsg cancel <3C512D69.4F572E0_at_exesolutions.com> Date: Mon, 28 Jan 2002 02:15:40 GMT Message-ID: <cancel.3C512D69.4F572E0_at_exesolutions.com> X-No-Archive: yes Newsgroups: microsoft.test,alt.flame.niggers,comp.databases.oracle.server NNTP-Posting-Host: w088.z064003087.lax-ca.dsl.cnc.net 64.3.87.88 Lines: 1 Path: news.uni-stuttgart.de!news.fh-hannover.de!news-han1.dfn.de!news-nue1.dfn.de!newsfeed.r-kom.de!newsfeed.freenet.de!peer.news.opaltelecom.net!out.nntp.be!propagator-SanJose!in.nntp.be!news-in-sanjose!sjc-feed.news.verio.net!sea-feed.news.verio.net!news.verio.net!msrnewsc1!cppssbbsa01.microsoft.com!tkmsftngp01!tkmsftngp04!u&n&a&c&anceller Xref: news.uni-stuttgart.de control:40722378

This message was cancelled from within The Unacanceller's glorious new software, Lotus 1-2-3 For Rogue Cancellers. Received on Fri Jan 25 2002 - 04:03:21 CST