Re: The Fact of relational algebra (was Re: Clean Object Class Design -- What is it?)

D_at_B.A wrote:
> When insering into a collection does OODBMS locks the whole collection? Or
> programmer explicitly specifies the lock? Those questions are hard even in
> relational model; this is how predicate locks, for example, were invented.
> Predicate locks happened to be fundamentally unefficient, but at least the
> concept was identified. When object people don't even have a common object
> definition, how can they hope to be able to handle hard subjects like
> concurrency, for example?

Good point!

The tighter language binding of object databases in comparison to relational databases would theoretically allow beautiful and performant locking systems by using object callback methods.

Somehow all the large object database companies seem to have lost the fun at the development of new concepts some years ago and they drifted off to develop other products (like web server suites) instead of perfectioning object database technology. Why, I wonder?

> Of course, this issue doesn't matter for CAD systems, but I wonder are
there
> crazy people who implemented a banking system with OODBMS?

With todays products it would really not make too much sense: - Object database query functionality commonly is bad. - Locking technologies hardly is beyond page locking.

I am sure, both of these issues will change in the near future.

Kind regards,
Carl

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