Re: Objects and Relations
Date: Sun, 18 Feb 2007 14:30:51 GMT
Message-ID: <vqZBh.4332$SR.774_at_trndny06>
"David BL" <davidbl_at_iinet.net.au> wrote in message
news:1170723701.183064.263580_at_h3g2000cwc.googlegroups.com...
> On Feb 6, 5:01 am, Kenneth Downs <knode.wants.t..._at_see.sigblock>
> wrote:
> > Walt wrote:
> >
> > >> > All databases, RM or otherwise, are about record-keeping. That is
> > >> > their purpose.
> >
> > >> I presume by "keeping" you mean persistence. By "record" do you mean
> > >> a tuple of a relation? If so I don't agree. An RDB is about
"record
> > >> keeping", but not an OODB (used appropriately).
> >
> > > I don't think the term "record-keeping" is closely related to the term
> > > "record" as you assert above.
>
> > > Record-keeping predates electronic computers.
>
> > Yup. I abandoned this thread as soon as I saw that it was never going
to be
> > about down-to-earth ideas.
>
> Down to earth as in "muddy"? :)
>
> Could you please define in more detail what "record keeping" means?
> For example does it include the recording of large amounts of text?
>
> I think your characterisation of database versus programs (record
> keepers versus taxis) has to do with persistent state versus transient
> state, or perhaps disk versus memory+CPU rather than with the
> distinction between relational (state) and OO (state).
There are three ways you can add value to data:
You can process it.
You can store & retrieve it.
You can convey it.
The "taxi" analogy is mostly about conveying data. The "record keeping" phrase is mostly about storage & retrieval. "transient state" is mostly about processing data (transforming, reducing, reformatting, etc. etc.)
>
> I note that systems based on RM provide the means to manipulate the RM
> state. So it doesn't seem quite right to say that RM is about
> passive state and OO is about active state. Remember as well that
> most objects don't host their own threads and therefore are passive
> (meaning they only do things when a thread calls their methods).
>
> I claim that the distinction between OO and relational has a lot to do
> with the question of whether entities are inside or outside the
> abstract computational machine, noting that 1) secondary storage is
> part of the machine so persistence has nothing to do with it, and 2)
> at the system level both relational and OO based approaches are
> "active" so that has nothing to do with it either.
> Received on Sun Feb 18 2007 - 15:30:51 CET