From: Martijn Tonies
Date: January 15 2004 2:23pm
Subject: Re: table without primary key
List-Archive: http://lists.mysql.com/mysql/157700
Message-Id: <038301c3db73$1b33fde0$0e02a8c0@martijn>
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Hans,

> I use it as a temporary file. Putting data in it sequential and after that
> reading it out sequential. I don't want a auto increment field or
> whatsoever because I want the date in sequential order of the data... the
> data itself cannot (always) be used as a primary key

If you don't have a "sequence" number of some kind, why do you
expect the data to be "sequential". I'm not sure about MySQL, but
from other systems I know, that if you don't specify an ORDER BY
clause (in your case: order by sequential_number), the order in
which the data is returned is "implementation defined". This can be
one of the following:

1) according to a primary or clustered index
2) in whatever order the rows are stored on disk

Usually, it's 2.

With regards,

Martijn Tonies
Database Workbench - developer tool for InterBase, Firebird, MySQL & MS SQL
Server.
Upscene Productions
http://www.upscene.com