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Re: vehicle to autoparts relationships

From: NENASHI, Tegiri <tnmail42_at_gmail.com>
Date: Thu, 23 Nov 2006 19:08:11 +0100 (CET)
Message-ID: <Xns988485A70B7BDasdgba@194.177.96.26>


"Aloha Kakuikanu" <aloha.kakuikanu_at_yahoo.com> wrote in news:1164246619.561011.4440_at_k70g2000cwa.googlegroups.com:

>
> NENASHI, Tegiri wrote:

>> "Aloha Kakuikanu" <aloha.kakuikanu_at_yahoo.com> wrote in
>> news:1164244417.310045.85570_at_e3g2000cwe.googlegroups.com:
>> > NENASHI, Tegiri wrote:
>> >> 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  ?
>> >
>> > No nested relations.
>>
>> Then how you create the schema ?  Please show with tables: what is it
>> that assemblyPartNo references ?

>
> (referred to the rifle diagramm example above)
>
> table Parts:
> part# partName
> ------ -------------
> 100 - BARREL
> 102 - BARREL NUT
> 104 - BARREL EXTENSION
> 108 - BARREL RETAINER
> 110 - BOLT
> 112 - EXTRACTOR
> 114 - EXTRACTOR AXIS
> 116 - EJECTOR
> ...
> 194 - EXTRACTOR SPRING
> ...
>
> table AssemblyParts:
> assemblyPart# part# partName
> ----------------- ----- -------------
> 1 112 EXTRACTOR ASSEMBLY
> 1 114 EXTRACTOR ASSEMBLY
> 1 194 EXTRACTOR ASSEMBLY
> 1 112 BOLT ASSEMBLY
> 1 114 BOLT ASSEMBLY
> 1 194 BOLT ASSEMBLY
> 1 110 BOLT ASSEMBLY
> 1 116 BOLT ASSEMBLY
>
> In this particular example we see that
>
> {112,114,194} <= {112,114,194,110,116}
>
> in other words, BOLT ASSEMBLY includes EXTRACTOR ASSEMBLY.

Then, it is not the set containment join that one can utilize but perhaps the set containment division; but one has to know what queries you suggest to execute to make it clear. Never the less, the performance problem is still there even if it is a set containment division.

>
Received on Thu Nov 23 2006 - 12:08:11 CST

Original text of this message

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