From: Hal Fulton <hal9000@...>
Date: 2005-03-25T13:50:23+09:00
Subject: OO database concepts...

I've been thinking about OO databases -- never having really
used such a beast. In fact, I am not sure that OOD even exist
in the sense that I would like.

Here's one thing I'm thinking about...

When one class inherits from another, we take it for granted
that they are "type compatible." Anywhere a Mammal can be
used, we can specify a Dog. (Insert standard discussion of
duck typing here.)

I'm thinking of the usual paradigm where a table is an ordered
sequence of fields. Neglecting the methods (which is another
issue entirely), we can think of the fields as instance vars.

But if a have a database table of Mammals... I can't store a
Dog in it. Hmm. I think I wish I could?

And don't get me started on singletons. Basically, the traditional
relational model assumes a fixed set of fields; but Ruby makes no
such assumption. Even objects of the same class may have different
attributes and methods.

Would it make sense to create a database that modeled Ruby's
paradigm more closely? Am I talking nonsense?


Thanks,
Hal