Hierarchical/network/OO dbms's

Hierarchical/network/OO dbms's

Post by Ben » Sun, 15 Jun 2003 19:31:46



Could anyone point me towards some dbms' based around the hierarchical, network
and OO models?  Preferably Linux and open source, but anything will be
of help.

Thanks  
Ben

 
 
 

Hierarchical/network/OO dbms's

Post by Mirch Masal » Sun, 15 Jun 2003 21:08:02



Quote:> Could anyone point me towards some dbms' based around the hierarchical,
network
> and OO models?  Preferably Linux and open source, but anything will be
> of help.

> Thanks
> Ben

For OO models, you could try this site:

http://www.javaskyline.com/database.html

which is fairly comprehensive. However, the focus is Java. If that is not
your cup-of-tea, try:

http://www.cetus-links.org/

where there are some pages on OO-related products, though some of the pages
have not been updated for a long time. That may have changed, since I have
not checked recently.

HTH

 
 
 

Hierarchical/network/OO dbms's

Post by Daniel Dudle » Mon, 16 Jun 2003 01:52:25



Quote:> Could anyone point me towards some dbms' based around the
> hierarchical, network and OO models?  Preferably Linux and
> open source, but anything will be of help.

Please don't multi-post to newsgroups, Ben. :-(
Cross-posting is alright because replies will appear in all
of the relevant newsgroups, which is not the case with
multi-posting.

I've posted a useful reply to comp.databases.theory, which
(because of your multiposting) will only be seen by
subscribers to that newsgroup. :-(

Daniel

 
 
 

Hierarchical/network/OO dbms's

Post by John Sas » Thu, 19 Jun 2003 08:28:48



> http://www.cetus-links.org/

> where there are some pages on OO-related products, though some of the pages
> have not been updated for a long time. That may have changed, since I have
> not checked recently.

It seems like there hasn't been any updates to the web site.
I tried to report a dead link and some new links some times, the page to
accept these updates didn't work always.

Does anyone know what's happening to the web site?

John

 
 
 

Hierarchical/network/OO dbms's

Post by Rob Twee » Fri, 20 Jun 2003 03:29:56


Check out Cache' from Intersystems (www.intersystems.com)

Cache' is an OO database, but at its core is a hierarchical data store
(see www.mgateway.com/extreme1.doc), so it may be of interest to you.
It's available for Windows, Linux, Unix and VMS

Rob


>Could anyone point me towards some dbms' based around the hierarchical, network
>and OO models?  Preferably Linux and open source, but anything will be
>of help.

>Thanks  
>Ben

---
Rob Tweed
M/Gateway Developments Ltd

Global DOMination with eXtc : http://www.mgateway.tzo.com
---

 
 
 

Hierarchical/network/OO dbms's

Post by Bob Badou » Fri, 20 Jun 2003 05:06:46


Hierarchic? Not even network!?! Man, oh man, that's primitive!


> Check out Cache' from Intersystems (www.intersystems.com)

> Cache' is an OO database, but at its core is a hierarchical data store
> (see www.mgateway.com/extreme1.doc), so it may be of interest to you.
> It's available for Windows, Linux, Unix and VMS

> Rob


> >Could anyone point me towards some dbms' based around the hierarchical,
network
> >and OO models?  Preferably Linux and open source, but anything will be
> >of help.

> >Thanks
> >Ben

> ---
> Rob Tweed
> M/Gateway Developments Ltd

> Global DOMination with eXtc : http://www.mgateway.tzo.com
> ---

 
 
 

Hierarchical/network/OO dbms's

Post by Ed Procha » Sat, 21 Jun 2003 11:20:06



> Could anyone point me towards some dbms' based around the hierarchical, network
> and OO models?  Preferably Linux and open source, but anything will be
> of help.

> Thanks  
> Ben

Just curious. Why the interest in the Hierarchical and network models? They
can be tough to maintain.

--
Ed Prochak
running    http://www.faqs.org/faqs/running-faq/
netiquette http://www.psg.com/emily.html
--
"Two roads diverged in a wood and I
I took the one less travelled by
and that has made all the difference."
robert frost

 
 
 

Hierarchical/network/OO dbms's

Post by James Fore » Sat, 21 Jun 2003 15:31:24


Matisse has a very simple object model unlike other object databases
that are kind of relying on some programming language. Matisse's
object model is basically consisting of only three things; class,
attribute, and relationship. Simple, huh?

Check it out at www.matisse.com. They provide good documentations.

(Oh, their db server is not open source, but language bindings
are open source)

HTH,
James


> Could anyone point me towards some dbms' based around the hierarchical, network
> and OO models?  Preferably Linux and open source, but anything will be
> of help.

> Thanks  
> Ben

 
 
 

Hierarchical/network/OO dbms's

Post by Bob Badou » Sun, 22 Jun 2003 00:51:24



Quote:> Matisse has a very simple object model unlike other object databases
> that are kind of relying on some programming language. Matisse's
> object model is basically consisting of only three things; class,
> attribute, and relationship. Simple, huh?

Not as simple as class and relation, though. You have one unecessary logical
entity: pointer or what you call relationship.
 
 
 

Hierarchical/network/OO dbms's

Post by Anthony W. Youngma » Sun, 22 Jun 2003 04:57:06





>> Could anyone point me towards some dbms' based around the hierarchical,
>network
>> and OO models?  Preferably Linux and open source, but anything will be
>> of help.

>> Thanks  
>> Ben

>Just curious. Why the interest in the Hierarchical and network models? They
>can be tough to maintain.

I notice you use the word "can". Relational databases can be tough to
maintain, too...

Basically, if you use the *appropriate* technology, and *design* it
properly, then your db should be easy to maintain. If your data doesn't
fall naturally into a relational model, but does fall easy into some
other model, then you should use that other model...

Cheers,
Wol.
--
Anthony W. Youngman - wol at thewolery dot demon dot co dot uk
Witches are curious by definition and inquisitive by nature. She moved in. "Let
me through. I'm a nosey person.", she said, employing both elbows.
Maskerade : (c) 1995 Terry Pratchett

 
 
 

Hierarchical/network/OO dbms's

Post by Bob Badou » Sun, 22 Jun 2003 06:52:37







> >> Could anyone point me towards some dbms' based around the hierarchical,
> >network
> >> and OO models?  Preferably Linux and open source, but anything will be
> >> of help.

> >> Thanks
> >> Ben

> >Just curious. Why the interest in the Hierarchical and network models?
They
> >can be tough to maintain.

> I notice you use the word "can". Relational databases can be tough to
> maintain, too...

> Basically, if you use the *appropriate* technology, and *design* it
> properly, then your db should be easy to maintain. If your data doesn't
> fall naturally into a relational model, but does fall easy into some
> other model, then you should use that other model...

Data are data. They do not fit into any one model more "naturally" than any
other model. Some models are simple and powerful; others are neither.
 
 
 

Hierarchical/network/OO dbms's

Post by Daniel Dudle » Sun, 22 Jun 2003 08:00:58








> > >> Could anyone point me towards some dbms' based around the
> > >> hierarchical, network and OO models?  Preferably Linux
> > >> and open source, but anything will be of help.

> > > Just curious. Why the interest in the Hierarchical and
> > > network models? They can be tough to maintain.

> > I notice you use the word "can". Relational databases can be
> > tough to maintain, too...

> > Basically, if you use the *appropriate* technology, and
> > *design* it properly, then your db should be easy to
> > maintain. If your data doesn't fall naturally into a
> > relational model, but does fall easy into some other model,
> > then you should use that other model...

> Data are data. They do not fit into any one model more
> "naturally" than any other model. Some models are simple
> and powerful; others are neither.

I disagree. A BOM, for example, fits far better (and
naturally) into the network model than the relational one.

But maybe I am misinterpreting your statement?

Daniel

 
 
 

Hierarchical/network/OO dbms's

Post by Carl Rosenberge » Sun, 22 Jun 2003 08:21:07



> Data are data.

This one is trivial:
TRUE

Quote:> They do not fit into any one model more "naturally" than any
> other model. Some models are simple and powerful; others are neither.

It's not that easy:
Some models use dead-simple flat data.
Some models use object orientation and inheritance hierarchies.
Some models use multiple inheritance.

You can model your application in different languages with different
technologies. Some possibilities are:
- UML
- Classes (possibly restricted to Java, where multiple inheritance
is not available)
- normalized tables

Depending upon the usecase, one of the above approaches may work better
than the other.

If you model your application with UML or classes, object databases
can understand the complete model directly, without the need to write
a single line of mapping code. That may spare you work.

No doubt, the relational model covers all of the above, but you may
have to specify a lot more relations in queries, where an object
database already "understands" what you want, because it "knows" the
class model.

Kind regards,
Carl
--
Carl Rosenberger
db4o - database for objects - http://www.db4o.com

 
 
 

Hierarchical/network/OO dbms's

Post by Bob Badou » Sun, 22 Jun 2003 09:32:21










> > > >> Could anyone point me towards some dbms' based around the
> > > >> hierarchical, network and OO models?  Preferably Linux
> > > >> and open source, but anything will be of help.

> > > > Just curious. Why the interest in the Hierarchical and
> > > > network models? They can be tough to maintain.

> > > I notice you use the word "can". Relational databases can be
> > > tough to maintain, too...

> > > Basically, if you use the *appropriate* technology, and
> > > *design* it properly, then your db should be easy to
> > > maintain. If your data doesn't fall naturally into a
> > > relational model, but does fall easy into some other model,
> > > then you should use that other model...

> > Data are data. They do not fit into any one model more
> > "naturally" than any other model. Some models are simple
> > and powerful; others are neither.

> I disagree. A BOM, for example, fits far better (and
> naturally) into the network model than the relational one.

Really? I used to write estimating software for electrical contractors, so I
have some familiarity with bills of material. And, in fact, at that same
time I used to maintain the source-code for a proprietary network model
dbms, so I especially have familiarity managing bills of material using
network model dbmses. I don't recall the network model providing any
benefits at all to help me do my job.

Presumably, you must know something about network model dbmses that gives
you some advantage for expressing operations on bills of materials. Can you
present a simple network model query to express an extended parts explosion?

Quote:> But maybe I am misinterpreting your statement?

You must be. How do pointers help describe a BOM or express operations on
BOMs? For instance, how does a pointer help me describe the cardinality of
component parts? eg. my remote control has 4 batteries. How does a network
model pointer express 4? What are the network operations that facilitate the
parts explosion and cost extension?
 
 
 

Hierarchical/network/OO dbms's

Post by James Fore » Mon, 23 Jun 2003 14:07:35





> > Matisse has a very simple object model unlike other object databases
> > that are kind of relying on some programming language. Matisse's
> > object model is basically consisting of only three things; class,
> > attribute, and relationship. Simple, huh?

> Not as simple as class and relation, though. You have one unecessary logical
> entity: pointer or what you call relationship.

That's not true.
In relational, you (need to) set primary key/foreign key constraint,
which is nothing but a (logical) pointer or relationship.
Matisse relationship is a set of logical OIDs. Its object model
is as simple as relatinoal one, and as powerful as relational
one, but much easier to build, read, and maintain.

In addition, the object model has class hierarchy.

James