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Re: vehicle to autoparts relationships

From: NENASHI, Tegiri <tnmail42_at_gmail.com>
Date: Thu, 23 Nov 2006 02:00:08 +0100 (CET)
Message-ID: <Xns9883CB7CEEE4Easdgba@194.177.96.26>


"Aloha Kakuikanu" <aloha.kakuikanu_at_yahoo.com> wrote in news:1164226982.397468.272020_at_b28g2000cwb.googlegroups.com:

> Contrary to what object people may say that assembling and
> disassembling things within a computer environment is not a big deal.
> It is certainly not a reason to dismiss relational approach.
>
> Now, there are some larger parts, ggregated from the smaller ones, for
> example, trigger assembly, or stock. How do we handle these? Simple,
> they are just sets:
>
> table AssemblyParts (
> assemblyPartNo integer, // informally it is a set#
> partNo integer, // foreign key to Parts
> );
>
> Granted, some of the interested queries become set joins, so you have
> to be familiar with the concept of set join. Other than that I don't
> see any problems. Do you?

You want to say the set containment join, is not it ? If you do, there are two problems: 1) the performance of set containment join; 2) the set valued attribute, or relation valued attribute, is not realised by all the databases. One can have a separate relation in the place of the relation valued attribute, of course, but then how does one reference the relation from AssemblyParts with assemblyPartNo ?

--
Tegi

>
Received on Wed Nov 22 2006 - 19:00:08 CST

Original text of this message

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