Re: Object-relational impedence
Date: Mon, 03 Mar 2008 22:33:58 GMT
"Bob Badour" <bbadour_at_pei.sympatico.ca> wrote in message
> David Cressey wrote:
> > "Roy Hann" <specially_at_processed.almost.meat> wrote in message
> > news:zpSdnSj5fPTYqVHanZ2dneKdnZydnZ2d_at_pipex.net...
> >>"Thomas Gagne" <tgagne_at_wide-open-west.com> wrote in message
> >>>JOG wrote:
> >>>>I wondered if we might be able to come up with some agreement on what
> >>>>object-relational impedence mismatch actually means. I always thought
> >>>>the mismatch was centred on the issue that a single object != single
> >>>>tuple, but it appears there may be more to it than that.
> >>>The issue as I've discovered it has to do with the fact OO systems are
> >>>composed of graphs of data and RDBs are two-dimensional.
> >>RDBs are not two-dimensional, they are n-dimensional. You are confusing
> > the
> >>picture of the thing with the thing. I have a three dimensional kitchen
> >>table. I have an RDB table with three columns (dimensions) called
> >>width and height that describes it.
> > Stop! You're both right!
> > There is a certain level of abstraction where and RDB is definitely
> > n-dimensional. This is the level of abstraction where I spend most of
> > time thinking. So I tend to agree with you, Roy.
> > There is, however, a different level of abstraction where an RDB is
> > two-dimensional. So Tom is not "wrong" all the way. And it may be at
> > level of abstraction where the OO RM impedance match comes about.
> David, the flaw in your logic is: At the level of abstraction where an
> RDB is two-dimensional, OO is uni-dimensional.
That would certainly explain the impedance mismatch! Received on Mon Mar 03 2008 - 23:33:58 CET