Re: Introducing PlayDB (The Model, The Language, The DBMS)

Read Date's and Darwen's _The Third Manifesto_, the book and not the 1995 paper, for a sound type inheritance model.

"Seun Osewa" <seunosewa_at_inaira.com> wrote in message news:ba87a3cf.0310091820.50180857_at_posting.google.com...
> Based on my own observations, I would like to define a class as:
>
> "A set of Objects/Entities percieved to have certain similar
> properties."
>
> In this definition there is no notion of hierarchy because that's the
> way it is in real life. A square is a rhombus, a rhombus is a
> parallelogram. A square is also a rectangle, which is not a rhombus,
> but is a parallelogram. So we would have difficulty defining one
> "superclass" for square. Then of course a parallelogram could turn
> out to be a rhombus on resizing, a rectangle could become auitable to
> join the group of squares on resizing, etc. And I think this is just
> the case in real world that the classES an object belongs to can also
> be dynamic. And when you look at the relational model, well, it
> requires you to choose a type for each item of data.
>
> What if an object could be a member of any arbitrary set of classes?
> What if this mapping of object to class was totally dynamic? It
> reminds me of interfaces in Java programming where an object can
> export an infinite number of interfaces, only that of course all this
> is dome at compile-time. Things could be come more
> complicat....err... interesting!
>
> Seun Osewa.
Received on Fri Oct 10 2003 - 04:33:15 CEST