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

"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?

> > 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? I'd be interested in how that would work, given that (I'm assuming much here) compression could work by comparing each frame, comparing it to previous and subsequent frames (or sets of frames), and producing some sort of "lossy delta". Given that frames are sequenced, and that the sequence is important for compression (assumption), how would one accomplish it using relations, which are order-agnostic and based on predicates applied to sets? Received on Thu Mar 04 2004 - 14:15:09 CET