Re: A question for Mr. Celko

> No no, that's not the problem, or at least not what I think is the
> problem. Date allows the NEST and UNNEST operations from the nested
> relational algebra. (He calls them GROUP and UNGROUP for some reason.)
> That means that you no longer consider them atomic because they allow you
> to split a nested relation into its constituent parts.

Does allowing this expression: StringVar[5] make the value in StringVar non-atomic? To me, the scenarios are exactly the same and the answer is no. A string is still a string whether or not you are allowed to access the components of the string. Similarly, a relation-value is still a relation-value whether or not it is contained within a relation-value itself. I don't see how this changes the definition of atomic. Indeed, if you allowed relation-value attributes, but were not allowed to extract them from the relation, what use would they be?

Regards,
Bryn Received on Mon Jul 19 2004 - 20:38:57 CEST