Re: The wisdom of the object mentors (Was: Searching OO Associations with RDBMS Persistence Models)
From: J M Davitt <jdavitt_at_aeneas.net>
Date: Thu, 01 Jun 2006 01:48:55 GMT
Message-ID: <bIrfg.52074$P2.29_at_tornado.ohiordc.rr.com>
>
>
> Ah, back to the ad-hominems.
>
>
>
> I'm with you so far.
>
>
>
> Surely.
>
>
>
> Certainly there are application domains where I would not hesitate to
> use RDBs. There are also application domains where I would not think of
> using them at all. So for some application domains RDSBs work very
> poorly, and other mechanisms work much better.
>
>
>
> I disagree. There are many data representations that can be useful and
> fruitful. The oft touted formalism of RDBs is fine; but does not
> preclude other mechanisms. For example, simple data structure
> representations are sometimes much more convenient and efficient than an
> RDB. As another example, consider your laptop. A lot of data is
> organized on that laptop using a directory and file structure rather
> than an RDB. This seems to work quite well as a general purpose
> organizing principle. There is no hue and cry for our filesystems to
> suddenly be RDBs.
>
>
>
> Again I disagree. I agree that RDBs DO allow a technology
> independence. However, they are not the only means to achieve this.
> Again, consider filesystems. I am currently typing this on a macintosh
> that has a window open with MS windows running inside. The Windows
> filesystem can see into the mac file system with no trouble. Indeed,
> the virtual windows OS can see accross the network to another windows
> machine and see the files there. Filesystems seem to be quite
> technology agnostic.
>
>
> You might be surprised at the world I live in.
>
>
Received on Thu Jun 01 2006 - 03:48:55 CEST
Date: Thu, 01 Jun 2006 01:48:55 GMT
Message-ID: <bIrfg.52074$P2.29_at_tornado.ohiordc.rr.com>
Robert Martin wrote:
> On 2006-05-31 10:53:23 -0500, Bob Badour <bbadour_at_pei.sympatico.ca> said:
>
>> Robert Martin wrote: >> The decision to use SQL or Relational technology is NOT at the >> >>> core of the system. But the structure of the data IS. That >>> structure can, and should, be decided in a technolgy agnostic way for >>> as long as possible. >> >> >> And this is why I say that what you write is such ignorant tripe.
>
>
> Ah, back to the ad-hominems.
>
>> A logical data model provides the structure, manipulation and >> integrity for a formal system. A good logical data model imposes no >> particular structure on the data as a whole while it does provide a >> structure in which to represent data. In fact, the structure of the >> data itself depends largely on one's point of view. One drastically >> alters the appearance of any graph by starting at a different location >> and traversing the edges in different directions.
>
>
> I'm with you so far.
>
>> >> As a logical data model, the relational model works very well
>
>
> Surely.
>
>> while the available alternatives work very, very poorly by comparison.
>
>
> Certainly there are application domains where I would not hesitate to
> use RDBs. There are also application domains where I would not think of
> using them at all. So for some application domains RDSBs work very
> poorly, and other mechanisms work much better.
>
>> Even if one is forced to use a non-relational product, one would have >> to be a complete ignorant fool not to analyse the design relationally. >> It is, after all, the only formalism we have for data that is, itself, >> predicate logic and that treats all data symmetrically.
>
>
> I disagree. There are many data representations that can be useful and
> fruitful. The oft touted formalism of RDBs is fine; but does not
> preclude other mechanisms. For example, simple data structure
> representations are sometimes much more convenient and efficient than an
> RDB. As another example, consider your laptop. A lot of data is
> organized on that laptop using a directory and file structure rather
> than an RDB. This seems to work quite well as a general purpose
> organizing principle. There is no hue and cry for our filesystems to
> suddenly be RDBs.
>
>> >> As the only available symmetric data model, it is the only logical >> data model that even begins to allow one to consider data in a >> technology agnostic way.
>
>
> Again I disagree. I agree that RDBs DO allow a technology
> independence. However, they are not the only means to achieve this.
> Again, consider filesystems. I am currently typing this on a macintosh
> that has a window open with MS windows running inside. The Windows
> filesystem can see into the mac file system with no trouble. Indeed,
> the virtual windows OS can see accross the network to another windows
> machine and see the files there. Filesystems seem to be quite
> technology agnostic.
Using file systems to make your point is a very poor choice. Take a file, copy it over there. Identical content, different paths. Which is "real?" Which is a copy? Which one should I modify if I want my changes to persist? How do Suzie and Bob and Joey and Ron know which is the one I scribbled in? What's keeping track of that? A file system? No way!
These, and other, questions become de minimis in the relational model.
>> >> Given that, what you wrote above was self-contradictory while >> suggesting you live in some fantasy world where data may only ever >> appear in a single graph.
>
>
> You might be surprised at the world I live in.
>
>
Received on Thu Jun 01 2006 - 03:48:55 CEST