Re: Generic Modeling

From: James <jraustin1_at_hotmail.com>
Date: 4 Jan 2002 11:41:48 -0800
Message-ID: <a6e74506.0201041141.6943dde1_at_posting.google.com>


> > > First, 100 randomly arranged objects are not very useful.
> > Maybe not but sometimes reality is that way and chaos is the norm not
> > order
>
> This statement is pretty fatalistic. Can you provide an example of a
> realistic situation comprising 100 objects that have meaning when
> arranged in any arbitrary configuration of relationships?

Different kinds of toys or things in a kid's room. Some are on the shelf. Some are on the bed, some on the floor, some on the table, some in the hamper, etc. I am saying that it is easier for an oodb to represent/manipulate complex/variable/deep hierarchal data than for rdbs. The 100 randomly arranged object is at the extreme end at yet an oodb like XDb deals with it the same way it handle any other better origanized data. In rdbs you would need to either using many tables or resort to generic modelling in a few tables. This leads me to believe an oodb models data more generically than rdbs.

> > > I would say that an OODBMS has an advantage over an RDBMS when you are
> > > using an OO programming language for logic AND your serialization
> > > needs can be handled (nearly) transparently and efficiently by the
> > > OODBMS. An RDBMS has the advantage
> > > when your data has to be accessed by a non-OODBM system.
> >
> > XDb is not a serialization of objects in a oo programming environment.
> > XDb is a database like Access and SQL Server but much simpler and
> > smaller yet more flexible and faster. XDb is accessible via a simple
> > GUI interface and by programming environments capable of calling a
> > DLL, for example VB, VB Script, ASP, C, C++, ASP, Delphi
> > (www.xdb1.com/Dev/API).
> >
>
> In what way is XDb like SQL Server?
It is mostly an apple-to-orange comparison.

> SQL Server supports multiple users. XDb doesn't.
No it doesn't. Multiple accessess would have to be serialized.

> SQL Server can survive a brief power outage. XDb can't.
No it can't (On should use a UPS and make backups with XDb).

> SQL Server databases can be larger than 2GB. XDb databases can't.
No it can't, until it is available for 64-bit processors like Itanium, in which case XDb should be able to access approximatly 2^41 bytes. But 2GB is large enough for many application.

> SQL Server implements transactional processing. XDb doesn't.
No it doesn't.

> SQL Server supports an interpreted, declarative query language.
> XDb doesn't.
Yes it does, but is quite rudimentary compared to SQL.

www.xdb1.com/Basics/Query.asp
www.xdb1.com/CreateQuerySimple.asp
www.xdb1.com/CreateQuery.asp

However, it can perform some queries which would be very difficult/impractical in SQL Server due to complexity or performance.

> SQL Server supports access control via locking. XDb doesn't.
No it doesn't. All access would have to be serialized.

> I guess they both hold data, but other than that there is little basis
> for comparison between the feature sets of XDb and SQL Server.
> SQL Server uses the relational model. XDb uses an object model.

Yes, XDb does have many limitations and is not appropriate for many applications, but it excel in 3 things:
1. It is small, fits on a floppy.
2. It is extremely fast, probably 10 to 1000 faster than SQL Server especially when dealing with complex/variable/deep hierarchal data. 3. and most importantly, it models data in a more general manner than rdbs as should be apparent by the prior 100 object example. Received on Fri Jan 04 2002 - 20:41:48 CET

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