Re: Unknown SQL

Bob Badour wrote:
> >> In an OODBMS, the DBMS will not delete the
> >> enrollment until all the references to it are gone. IE. one must delete
> >> both the student and the class before the enrollment disappears.
> >
> >We are just about to release a callback interface for cascading deletes.
>
> And this is supposed to be simpler than just declaring a cascading delete?
> LOL
Cascading the delete is exactly one line of code: container.delete(member);

In addition the concept is much more powerful than cascaded-delete in relational databases. The programmer has manual control to check conditions and to take additional actions.

> Add Callback to the list of concepts your users must learn and understand.
> Add it to the list of physical implementation details your product exposes
> in the logical interface to the user.

Indeed, this is an additional concept but the programmer does not need to worry about it, if he does not wish to use it.

> When someone decides to switch to a different vendor's OODBMS, how do you
> propose they transport constraint meta-data obfuscated in a procedural
> callback function?

Callback events are is common among object database implementations. Since all actions taken remain within the users application classes, the feature is perfectly portable.

I don't know this, really:
How are cascaded deletes portable between relational databases? How are they deployed?
Is there a standard?

Kind regards,
Carl

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