Date: Tue, 06 Nov 2007 16:22:34 GMT
Roy Hann wrote:
> I have been on the fence about RVAs for years. I can see why Date and
> others (including you guys) want to talk about them for the purpose of
> understanding where the theory takes you. But this little exchange shows me
> that I never want to see RVAs implemented in any product. (I am not talking
> about paul's confusion about the relations in question.)
> I don't care if there is a problem that can be solved only with RVAs, the
> misery they would invite just wouldn't be worth it. The old joke says if we
> ever teach computers to understand English we will find out that programmers
> can't write it. If we ever produce a product that supports RVAs we will
> find out programmers are wanting in that area too.
Even though they seem to make logical sense, I'd have to agree with anybody who says they are cumbersome and might be a PITA for a programmer who had to use them all them day long. Just because something might be a logical possibility doesn't make it reasonable in general.
One thing that annoys me about them is how they allow two attributes with the same name to be thought of as "in the same outer relation", if you will. I find it hard to even talk about them without using "nested English". I can imagine an EAV fanatic using them to make a system where every query or change requires RENAME clauses.
But I'd like to suggest that even though I throw the term RVA around, pretty loosely too, I'm not sure all these posts have been about RVA's but rather something else, even if that something else is not well defined in the context of the rest of RT. Perhaps "set-valued attributes" describes it better. These might just be a figment of my imagination, as I have been expressing them rather casually, assuming that there is a way to define a relation that could avoid RENAME when it is manipulated. Received on Tue Nov 06 2007 - 17:22:34 CET