Re: Object-relational impedence

On Mar 12, 9:34 am, S Perryman <q..._at_q.com> wrote:
> JOG wrote:
> >>On 2008-03-08 21:39:37 -0600, JOG <j..._at_cs.nott.ac.uk> said:
> > A red herring as far as I'm concerned this Robert - after all RM is
> > not an "inference engine" either. What I am questioning whether we
> > need the concept of inheritance /whatsoever/. It does not exist in
> > logic, it has no underlying theoretical justification, and is purely
> > an ad hoc mechanism thrown together at xerox parc.
>
> 1. Devised at the NCC in Norway, not Xerox PARC.

Much obliged.

>
> 2. Devised because of the influence of academic work on data types (Hoares'
> "record" types) , and noticing things having related properties/behaviours
> in simulation systems.
>
> So not really ad-hoc (thought went into providing the scheme) .

Remember that there is a huge amount of 'academic work' on XML - that doesn't make XML any the less ad-hoc, or without sound theoretical foundation. But again thanks for the info, and if you have any links to the things you site, I'd be interested to having a look.

>
> > Is it not true that
> > inheritance has lost favour over the years - composition is generally
> > preferred, unless one is defining interfaces (and whether that should
> > still be called "inheritance" is open to debate).
>
> As a property acquisition/composition scheme, certainly.
> As a type substitutability mechanism, (sadly) no (Java, C# etc) .
>
> Regards,
> Steven Perryman
Received on Wed Mar 12 2008 - 11:17:17 CET