Re: Clean Object Class Design -- What is it?

David Cressey wrote:
> I'm not sure exactly what you mean by "embedding our database into
> applications". The only way I can interpret it is to mean PRECISELY what
> the inventors of database systems in the 1970s were trying to get away
 from:
> the idea that all the data definitions were buried somewhere in source
 code,
> and the only way to manage data definitions was to get involved in the
> details of source code maintenance.

The systems in the 70s were *not* object-oriented.

With the arrival of objects, you have a representation of the real world which is not "buried" in code. Today people are using UML to model objects and relations between them. What is wrong about storing the evolved model without change? For me an object model is much easier to understand than a dozen of tables that are linked together. I could equally argue that a relational database "buries" the object model in tables.

Assume that you want to preserve the state of some objects in your application for the next session or possibly send them to another place in the world. Isn't it convenient to have a tool that does as much of the work necessary as possible? This is what Java serialisation was created for. In comparison to serialisation we reduce the storage overhead, make the mechanism much faster, detect and allow changes in the class scheme, allow memory management to control what is instantiated when and provide funtionality to query the stored objects. What's wrong with the approach?

If you write a parser with somewhat 100 different nested classes that have a complex inheritance hierarchy, couldn't it be convenient to store the nodes without having to maintain a database scheme? Usecases differ so widely that a discussion "this database is better" can never lead to a result. Bob Badour denies that object databases may be useful at all. I neither understand where he comes from nor what he is up to.

Using insults, talking about the old-days 30-years-ago or turning definitions like "network-model whatevers" around in circles does not change the attitude of our users that like our system. I don't know a better proof-of-concept than a happy mail by a user that encourages me to continue development. As long as this kind of feedback keeps coming, I can only laugh at some of the points put forward in this thread.

Kind regards,
Carl

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Carl Rosenberger
db4o - database for objects - http://www.db4o.com