Re: Generic Modeling

> You can't compare tables to objects.
> Keep in mind the following analogies:
> (object : class)
> :: (tuple : relation)
> :: (row : table)

In rdbs, a table and row are distinctly different types of things. Each has different properties and methods.

In XDb, an object can be a class, an instance or both at the same time and they have nearly the same properties and methods. It is this type of orthogonality that allows an oodb to implement solutions in a more general manner than rdbs.

In XDb, each object is the instance of its class. In turn, each instance can be the class for new instances and this process can be extended. Therefore, an object can be both a class and an instance. The root is the ancestor class of all other objects and is the only object without a class (or parent).

For example, Person is the instance of Root. John, Mary and Doctor are instances of Person. Dr. Brown, Dr. Smith and Surgeon are instances of Doctor, etc.

Are you modelling inheritance of this type in your "generic model"? Received on Fri Jan 04 2002 - 23:58:49 CET