Re: OO foundation

Marshall wrote:

>On Mar 5, 7:58 am, "H. S. Lahman" <h..._at_pathfindermda.com> wrote:
>>
>> ... the relational model is a subset of the OO foundation ...
>
>Please describe where JOIN and UNION for example,
>are to be found in the OO foundation. Or in any OO language.

Generally, it requires a combination of OO with functional idioms (higher order functions, closures). Today's .NET languages support that; so do more dynamic languages such as Smalltalk, Perl, Python or Ruby; C++ templates support it. In Java we still have to fake them with inner classes, I believe.

Of course there is still a difference: JOIN and UNION are symmetric, assuming a helicopter perspective in which the data manipulator has full access to all of the data, while the OO world is inherently asymmetric (code can only work see data explicitly exposed to the class the code is in).

-- 
Reinier