Re: EAV (Re: Object-relational impedence)

From: topmind <topmind_at_technologist.com>
Date: Thu, 20 Mar 2008 13:11:35 -0700 (PDT)
Message-ID: <c92a753c-cc3b-4f8f-a046-fe41eb88c5ed_at_d21g2000prf.googlegroups.com>


On Mar 20, 11:43 am, frebe <freb..._at_gmail.com> wrote:
> On 20 Mar, 18:39, topmind <topm..._at_technologist.com> wrote:
>
> > David Cressey wrote:
> > > "Eric" <e..._at_deptj.demon.co.uk> wrote in message
>
> > > > EAV is a way of misusing an RDBMS, and could be used for any subject
> > > > domain - and your schema description sounds like EAV.
>
> > EAV (attribute/value pair tables) is not always bad. It is one
> > approach to allowing user-definable "columns" and/or times when
> > dynamicy is needed so that a DBA does not have to do the new-column-
> > shuffle all the time.
>
> > I agree it can be a performance killer in some circumstances, but
> > often that's the tradeoff for flexibility.
>
> Using existing mainstream software development tools, I would agree
> that EAV is an necessary evil in many cases. The obvious solutions is
> of course to have better 4GL tools, which allow developers to more
> easily add fields in the database and the GUI. A while ago I had the
> doubtful pleasure of working with an application which was 100% EAV,
> and the flaws was pretty obvious. I have never seen such bad
> performance.
>
> //frebe

http://www.c2.com/cgi/wiki?DynamicRelational

-T- Received on Thu Mar 20 2008 - 21:11:35 CET

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