Re: sql views for denomalizing

Marshall Spight wrote:
> dawn wrote:
> >
> > That's where I get messed up because instead of just showing the view,
> > I have to massage that view simply because one of the attributes on the
> > page has cardinality greater than 1.
>
> Says who?
>
> First of all, even existing SQL products allow *some* attributes
> to have > 1 cardinality: varchar.
>
> Second, a variety of authors advocate nested relations, either
> not considering them to violate 1NF (Date et al) or not caring.
> (Me, say.)

I'm thinking of data that are already stuck in an RDBMS, so perhaps this can be done now. I see the Dataphor example. Are there examples in other SQL-DBMS tools that would yield a similar result?

> Third, who says you have to do the whole webpage with just a single
> view?

No one, just as you don't have to update with a single view for one service. However, this "requirement" gives a picture of what I'm trying to do logically which is why I stated it that way. When developing an application, I will need to model the data for CRUD and model the data for a UI. I would like to use the same modeling techniques for both, rather than modeling the UI with grouping attributes (like "Address" including all components of such) and multivalues and the CRUD without such.

>
> > If the view is supposed to be the view of the data, then why do we have
> > this 1NF restriction when we don't care about the other NF's in a view?
>
> I don't agree that we do. In theory.

It seemed that we did in theory until very recently and, for the most part, we still teach a theory that says that all NF depend on getting data into 1NF the way it is defined by all SQL-DBMS's I have ever worked with.

OK, so is the Dataphor approach the way that SQL-DBMS's are moving, or is it unique? Is the industry in agreement that relational databases should have views that permit multivalues in the views? Are there target dates for this in any other SQL-DBMS?

If so, then onward to the next question -- is there anything in relational theory that would permit attribute names that span multiple attributes, such as address consisting of this, that, city, postCode, and the other thing? Is there any implementation of a relational model or a SQL-DBMS that permits this?

Thanks a bunch! --dawn

>
> Marshall
>
> PS. Remember, this is the *theory* newsgroup.
Received on Sat Jul 30 2005 - 16:58:01 CEST