Re: EAV (Re: Object-relational impedence)
Date: Thu, 20 Mar 2008 11:43:16 -0700 (PDT)
Message-ID: <03b4e3a3-4e32-4ee0-aae0-dbe696318606_at_h11g2000prf.googlegroups.com>
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 Received on Thu Mar 20 2008 - 19:43:16 CET