Re: Codd provided appropriate mathematics ... (was Re: Relational and MV (response to "foundations of relational theory"))

"Eric Kaun" <ekaun_at_yahoo.com> wrote in message news:xZF1c.30932$gA7.13354_at_newssvr16.news.prodigy.com...
> "Bob Badour" <bbadour_at_golden.net> wrote in message
> news:1YKdnT0pBP2Z_tvdRVn-uQ_at_golden.net...
> > "Eric Kaun" <ekaun_at_yahoo.com> wrote in message
> > news:cgl1c.55383$3T6.34195_at_newssvr33.news.prodigy.com...
> > > In Java I tend to use iterators, so I deal more with a "sequence" type
> > than
> > > a list per se. The usual defining characteristics of a list are
ordering
> > > and, in most cases, random indexed access to elements.
> >
> > How does an iterator fit with operations on values?
>
> An iterator allows access to the elements of the list (and, incidentally,
is
> provided for all container types). I assume one of the operations on a
list
> would be extracting an element, but of course that quickly gets you out of
> the domain of lists. Hmmm. What operations were you thinking for a "List
> Type" that would be a reasonable fit in a relation?

I have no particular use for lists at the logical level.

> > > Agreed - the only reason might be, for example, a COMPRESS operation
> which
> > > takes a FRAME_LIST and returns a FRAME_LIST which takes less space
when
> > > serialized (lossy compression).
> >
> > And why does one need an array etc. instead of a relation for the
compress
> > operation?
>
> So you're thinking of a view which produces the compression?

No, I am thinking of compression as a physical issue unrelated to the logical interface. Received on Wed Mar 10 2004 - 03:42:48 CET