Re: In an RDBMS, what does "Data" mean?
Date: Wed, 16 Jun 2004 17:44:19 -0500
Message-ID: <caqig4$sdf$1_at_news.netins.net>
"Eric Kaun" <ekaun_at_yahoo.com> wrote in message
news:n61Ac.54$NZ6.29_at_newssvr33.news.prodigy.com...
> "Anthony W. Youngman" <wol_at_thewolery.demon.co.uk> wrote in message
> news:H1hmm5EGEfyAFwYZ_at_thewolery.demon.co.uk...
> > In message <ca874t$g9t$1_at_news.netins.net>, Dawn M. Wolthuis
> > <dwolt_at_tincat-group.com> writes
<snip>
> Except that your query language is less symmetrical as a result of
treating
> assertions about line items differently than other predicates. At this
point
> I'm just repeating myself though...
Oddly enough, it (typically) is symmetric because we work with named derived data. The symmetry is not based on how the data are stored, but on the logical structure, so that
LIST PEOPLE COMPANIES
(not yelling, just getting in touch with the old caps-lock approach)
and
LIST COMPANIES PEOPLE
are both queries. However, in the case of a phone number, if PEOPLE
includes PHONE_NUMBERS then we would have
LIST PEOPLE PHONE_NUMBERS
but not LIST PHONE_NUMBERS PEOPLE
That is the same as you would see with a relational implementation where there is just one phone number and it is an attribute of a person relation.
select phone_number from person
but not
select person from phone_number
Am I missing something re your concern for symmetry in the reporting language? --dawn Received on Thu Jun 17 2004 - 00:44:19 CEST