Re: Advice on SQL and records
From: Jonathan Leffler <jleffler_at_earthlink.net>
Date: Mon, 22 Aug 2005 05:21:01 GMT
Message-ID: <1hdOe.9283$Wi6.3610_at_newsread2.news.pas.earthlink.net>
>
> Neit[h]er one. The StudentClasses table has only two attributes: a
> student id and a class id. It exists to model what students are in
> what classes, and not any facts about students or classes per se.
Date: Mon, 22 Aug 2005 05:21:01 GMT
Message-ID: <1hdOe.9283$Wi6.3610_at_newsread2.news.pas.earthlink.net>
Marshall Spight wrote:
> fran_beta_at_hotmail.com wrote:
>>It seems implicit from what you say that StudentClasses includes all >>ClassID records AND all StudentID records, whereas I assume that only >>ClassID records would be in there.
>
> Neit[h]er one. The StudentClasses table has only two attributes: a
> student id and a class id. It exists to model what students are in
> what classes, and not any facts about students or classes per se.
Wouldn't the StudentClasses table also contain information relevant to the particular student's achievements in the particular class? That is, while it would undoubtedly contain the two attributes you identify, it might also contain other information?
-- Jonathan Leffler #include <disclaimer.h> Email: jleffler_at_earthlink.net, jleffler_at_us.ibm.com Guardian of DBD::Informix v2005.02 -- http://dbi.perl.org/Received on Mon Aug 22 2005 - 07:21:01 CEST