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Home -> Community -> Usenet -> comp.databases.theory -> Re: An object-oriented network DBMS from relational DBMS point of view

Re: An object-oriented network DBMS from relational DBMS point of view

From: JOG <jog_at_cs.nott.ac.uk>
Date: 12 Mar 2007 18:33:31 -0700
Message-ID: <1173749610.986282.144060@j27g2000cwj.googlegroups.com>


On Mar 13, 12:26 am, "topmind" <topm..._at_technologist.com> wrote:
> On Mar 12, 4:54 pm, "JOG" <j..._at_cs.nott.ac.uk> wrote:
>
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> > On Mar 12, 6:08 pm, "Dmitry Shuklin" <shuk..._at_bk.ru> wrote:
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> > > On 10 อมา, 18:32, "JOG" <j..._at_cs.nott.ac.uk> wrote:
>
> > > > - Row A says Aristotle is a Row Z
> > > > - Row Z says a Human is a mortal.
>
> > > No,
> > > Row A has attribute Name = "Aristotle" and attribute Type = RowZ
> > > Row Z has attribute Lifetime = "mortal"
>
> > > So here is one join
>
> > Hi dimitry,
>
> > First let me make it clear i'm an OO coder, as well as having an
> > interest in db theory so I don't have an vested interested in one area
> > more than the other. However I sincerely believe that DB theory over
> > the past 30 years has progressed information modelling through its
> > abandonment of OID's - essentially enforcing that there is no identity
> > outside of attributes. After all this is how we perform identification
> > outside of a system, and so there seems no reason to think we should
> > require an extra mechanism once we are encoding information
> > (especially now our models are logical ones completely separated from
> > physical layer considerations). Row identifiers hence seem
> > superfluous, adding an unnecessary layer of complexity that doesn't
> > actually give me anything /extra/.
>
> > Like yourself, I believe there may be scope for a useful middle ground
> > between object and relational approaches (despite their philosophical
> > differences). But I'm not sure what you propose is that middle-ground.
> > Get rid of those OID's, allow me to join objects and work
> > declaratively, and I'll be all ears. J.
>
> To clarify, I hope you are not ruling out system-generated ID's (such
> as sequentially-assigned employee ID's).

Indeed not, and it is a good distinction you have made - many are confused by the difference between a system generated surrogate and an OID. Once created the former exists outside the system (its part of the proposition being recorded after all), as valid an attribute as any other of the item being referred to.

> These can be quite useful in
> practice. Ideally domain attributes would do the job of unique
> identification alone, but it often does not pan out that way. (The
> biggest difference between RDBMS generated ID's and object-ID's is
> that the DB ones "stay" and are not tied to physical RAM.)
>
> -T-
Received on Mon Mar 12 2007 - 20:33:31 CDT

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