Re: EAV (Re: Object-relational impedence)

On 21 mar, 14:30, Eric <e..._at_deptj.demon.co.uk> wrote:
> On 2008-03-20, topmind <topm..._at_technologist.com> wrote:
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> > Eric wrote:
> >> On 2008-03-20, topmind <topm..._at_technologist.com> wrote:
> >> > 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
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> >> >> > > > 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.
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> >> >> > I agree it can be a performance killer in some circumstances, but
> >> >> > often that's the tradeoff for flexibility.
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> >> >> 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.
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> >> >> //frebe
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> >> >http://www.c2.com/cgi/wiki?DynamicRelational
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> >> What on earth are you trying to prove by referencing that?
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> > It was not to "prove" anything, but show *potential features* of a
> > dynamic relational system. (Some don't like dynamic relational, but
> > that's like the ol' Smalltalk versus Eiffel fights, except with
> > relational instead of app langs.)
>
> And how much of it did you write? Looks to me like adding flexibility to
> the RM by removing defining features, also like solving a non-existent
> problem. But both of those are separate arguments.
Well put. The definition of OO *flexbility* can pretty much be summed up to *no constraints, freedom*...Same ol story..

> I don't think it adds anything to this thread at all.
>
> E
Received on Fri Mar 21 2008 - 22:00:45 CET