Re: Modelling objects with variable number of properties in an RDBMS
From: VC <boston103_at_hotmail.com>
Date: Wed, 2 Nov 2005 06:00:46 -0500
Message-ID: <P6KdnREFdtrKAfXeRVn-jQ_at_comcast.com>
> 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
> Guardian of DBD::Informix v2005.02 -- http://dbi.perl.org/
Received on Wed Nov 02 2005 - 12:00:46 CET
Date: Wed, 2 Nov 2005 06:00:46 -0500
Message-ID: <P6KdnREFdtrKAfXeRVn-jQ_at_comcast.com>
"Jonathan Leffler" <jleffler_at_earthlink.net> wrote in message
news:YHY9f.4683$Rl1.3852_at_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
I know that, but what recipe does Roy suggest for, let's say, MS SQL Server that does not have either UDTs or other means to implement an entity with a higher than the table limit number of attributes, beyond offering a cute saying ?
> make it work.
> >> Email: jleffler_at_earthlink.net, jleffler_at_us.ibm.com
> --
> Jonathan Leffler #include <disclaimer.h>
> Guardian of DBD::Informix v2005.02 -- http://dbi.perl.org/
Received on Wed Nov 02 2005 - 12:00:46 CET