Re: The Foundation of OO (XDb)

Bob Badour wrote:

>>which again raises the notion of type inheritance.
>>
>Doing so only confuses logical and physical. The logical model does not care
>how the dbms physically represents the data. A video is a video. AVI, MPEG
>and QuickTime are all just representations of Video.
>

but not all subtypes have the semantics of implementation format of something (and depending on what you are trying to do, formats are not just a representation detail either, they do have different observable, functional characteristics). In another model, subtypes may exist to describe e.g. types of investment fund, or types of organisational unit. You cannot just hide the subtypes if that is the whole point of the model.

• thomas beale