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Re: Modelling objects with variable number of properties in an RDBMS

From: Jonathan Leffler <jleffler_at_earthlink.net>
Date: Wed, 02 Nov 2005 06:06:48 GMT
Message-ID: <YHY9f.4683$Rl1.3852@newsread1.news.pas.earthlink.net>


VC wrote:

> "Roy Hann" <specially_at_processed.almost.meat> wrote in message 
> news:9v-dnYE-SanY6PreRVnygg_at_pipex.net...
> 

>>"vc" <boston103_at_hotmail.com> wrote in message
>>news:1130765800.098046.93870_at_f14g2000cwb.googlegroups.com...
>>
>>>Roy Hann wrote:
>>>....
>>>
>>>>Actually no, let's not. What you have re-invented here is the tired
>>>>old
>>>>entity-attribute-value (EAV) design (much beloved of medical research
>>
>>wonks
>>
>>>>for some reason).
>>>
>>>Often they do that (EAV) not because they do not know any better but in
>>>order to overcome a specific database physical limitations. Their
>>>entities very often contain thousands of attributes (molecular
>>>biology/pharmaceutical research/drug discovery) [snip].
>>
>>Always check the bath water for babies...
> 
> 
> I beg your pardon ?


There's an old saying "Don't throw the baby out with the bath water". In this context, it means (roughly) make sure you don't lose the benefits of the relational model by thowing away all the rules that help make it work.

-- 
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 Wed Nov 02 2005 - 00:06:48 CST

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