Re: Inheritance

On Mon, 19 Aug 2002, Zeugswetter Andreas SB SD wrote:

> > So what you're saying is that constraints shouldn't be inherited?
>
> No. I even said that inheriting should be the default.

Ah. So you think it should be possible not to inherit constraints.

> A local constraint should be made obvious from looking at the schema,

Ok, this now I could live with. Though I'm not sure that its
theoretically very defensible, or worth the effort. Other languages
that offer constraints, such as Eiffel (and soon Java), do not allow
constraints that are not inherited, as far as I know. Do you have some
counterexamples.

> Well, that is where I do not think this is flexible enough, and keep in mind
> that all triggers and rules would then also need such restrictions.

Yes, all triggers, rules, and everything else would have to be inherited.

> Regardless whether your objection is *strong* or not :-)
> If you don't like the feature (to add a local constraint), don't use it.
> (Remember you are talking about removing an implemented feature)

1. It's not exactly an implemented feature, it's an accident of an
incomplete implementation of inheritance done in a certain way.

2. Should we change the way we decide to implement inheritance,
perhaps to make fixing the current problems much easier, it might
be a lot of work to add this.

cjs
--
Curt Sampson <cjs(at)cynic(dot)net> +81 90 7737 2974 http://www.netbsd.org
Don't you know, in this new Dark Age, we're all light. --XTC