[Data-modeling] "Inheritance"

[Michael Callaghan]

Thanks, Scott, for the detailed reply.


If there's no situation in which you would type an instance of
> person as SuperA but not as SubA (ie. SuperA is "abstract") then
> there's no reason for SuperA to exist.  There's no code in Freebase,
> so abstraction isn't really meaningful.  If you want all instances
> having certain properties, just ask for them, if necessary, using
> fully qualified property names.
>

You're right - SuperA is abstract.  Its role is to represent commonality
between SubA and SubB, and of course there is no "code" in Freebase to
process this intent.  However, I do want to be able to view "all topics that
have these common properties", and the key point you make is that, although
the default UI view behaviour doesn't cope too well with this (as described
in my original post) custom views can readily be defined which do the job
(and MQL can do almost anything we want it to).

In other words "abstract supertypes" are best thought of (and replaced by,
and dealt with as) common collections of properties.

As for the real data - I'm still pre-processing, cleaning and prototyping,
but I'm sure there'll be plenty more concrete discussions in the future.  In
the meantime, I can't be the only Freebase newbie that needed this issue
spelling out (again!).

Thanks again,
Michael
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