Re: [xmlvoc] data model

[Erik Wilde <net.dret@dret.net>]

hello.

on the issue of data models: this is one of the very 'soft' terms that 
people tend to define very differently. which is why i didn't do it so 
far in my glossary... however, i would like to draw your attention to 
rfc 3444 (ftp://ftp.isi.edu/in-notes/rfc3444.txt). rfc 3444 is more 
geared towards snmp applications, here are my interpretations of the two 
terms:

- An information model is an abstract description of the entities that 
are of concern in a given application area, as well as their relations. 
Specifically, an information model is not concerned with defining 
representations or interfaces or any other kind of access mechanism for 
the entities it is modelling. The goal of an information model is to 
identify, describe, and relate the entities of interest, not to define 
any specific means for representing, accessing, or manipulating them.

- A data model can be regarded as the lower-level implementation of a 
higher-level information model. Data models are based on two things, the 
first one being the information model they are implementing, the other 
one being the particular method they use for implementing it. This 
method may be the definition of a syntax for serializing the entities, 
or the definition of an API for accessing the entities from within 
applications.

i am sure that many people object to this view of the world, but i found 
it very useful when trying to convince people that the xml information 
set is, in fact, an information model, which may be implemented by 
various data models, such as dom, sax, or canonical xml.

cheers,

erik wilde  -  tel:+41-1-6325132  -  fax:+41-1-6321035
           mailto:net.dret@dret.net  -  http://dret.net
           computer engineering and networks laboratory
           swiss federal institute of technology  (eth)
           * try not. do, or do not. there is no try. *