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[protege-discussion] Function Feature List for Protege? Protege vs. a Database

Tania Tudorache tudorache at
Thu Jul 1 16:58:26 PDT 2010

I think the question is broader than Protege vs. databases, and it is 
rather: ontologies vs. databases.

Ontologies and databases solve different issues. An ontology is an 
abstract representation of a domain that can serve several purposes 
(e.g., just building or sharing a common understanding between experts, 
integration between different data sources, etc.). Some people would 
even argue that the instances (actual data) is not part of an ontology. 
The good thing about ontologies is that you can express things that hold 
in the domain you modeled: E.g. All humans are mortals, or all students 
are persons (not the ideal example, but it should work). And if you 
assert something about persons, it will also hold for students. So, it 
is really describing kind of general "rules" that hold in your domain. 
The fact that the ontology languages (e.g. OWL) have a formal semantics, 
also ensures that two different tools will have the same interpretation 
of your ontology and data (E.g. You assert in one tool, that John is a 
student, then based on some inference, John is also a person. Any other 
tool that "understands" OWL will make the exact same inference). Using 
that formal semantic, you can also check the consistency of your domain 
description, or to classify an instance under a class, or infer new 
facts in your domain.

  A database, on the other hand, is really for storing large amounts of 
data. It is not really about representing the "rules" that hold in a 
domain, or to make inferences. It does have a schema used to store the 
data, and you can define some constraints on the schema that can be 
enforced. But the type of constraints you express in a database vs. the 
axioms in an ontology are very different.

In fact, there is a very nice presentation from Ian Horrocks that deals 
with the differences between ontologies and databases that you can 
access here:

I am also interested to hear what other people think.


On 07/01/2010 01:14 PM, Ron Schultz wrote:
> Is there a document that summarizes the functions and features of 
> Protege? I know I can dig this out through all the documentation 
> present, but I was wondering if a summarization was available somewhere.
> I am running into issues in discussing the capabilities of Protege - 
> all too often someone in the audience asserts 'well - that's just a 
> simple database! Why use Protege - anyone can build that as a simple 
> database application.' I know from much personal experience that 
> that's not the case - but I am tired of answering this all too often 
> asked question. I want to be able to hand someone a list of functions 
> and features and say - 'Ok - here's what's required. Tell me what 
> database can do all this. Or tell me how much its going to cost to 
> write an application to do all this.'
> Any pointers or references would be much appreciated.
> Ron
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