W3C home > Mailing lists > Public > www-rdf-interest@w3.org > January 2001

Re: data smushing

From: <ssarkar@ayushnet.com>
Date: 4 Jan 2001 08:10:38 -0800
Message-ID: <20010104161038.9457.cpmta@c001.snv.cp.net>
To: www-rdf-interest@w3.org
Cc: Daniel.Brickley@bristol.ac.uk

Some thoughts ::

When we dig deeper into properties, aggregations
and relations within the complex web world of RDF/XML,
(I think) we are looking for a missing link over
relations, calculus and algebra. 
We mey need to travel similar path of thinking where 
first order logic was transformed into tuple 
calculus and then into relational algebra.


> > I'm not familiar with "unification hacking" but "smushing" is probably
> > more commonly called "aggregation".  
> It's just a cutesy term we've been using around here for databases that
> "go one better than URIs" when aggregating diverse RDF information into
> a common store.  


Relational databases decompose complex aggregations
(with nestings) with simpler aggregations (with
no nestings) by inheriting foreign keys. A similar
foreign-key/primary-key mapping and inheritance
will work fine in RDF/XML descriptions.  URIs can
uniquely identify a description becoming a primary
identifier. 


> Example Scenario
> 
> a.rdf 
> 
> <Company>
> <corporateHomepage web:resource="http://megacorp.example.com/"/>
> <name>MegaCorp Inc.</name>
> <ticker>MEGA</ticker>
> <owner>
>  <Person>
>  <name>Mr Mega</name>
>  <personalMailbox web:resource="mailto:mega@megacorp.example.com"/>
>  <personalHomepage web:resource="http://megacorp.example.com/~mega"/>
>  <age>50</age> 
>  </Person>
> </owner>
> </Company>
> 
> b.rdf 
> 
> <User>
>  <personalMailbox web:resource="mailto:mega@megacorp.example.com"/>
>  <technologyInterest web:resource="http://www.w3.org/XML/">
>  <technologyInterest web:resource="http://www.w3.org/RDF/">
>  <technologyInterest web:resource="http://www.mozilla.org/">
> </User>
> 
> c.rdf 
> 
> <Organisation>
> <corporateHomepage web:resource="http://megacorp.example.com/"/>
>  <ethicalPolicy>
>    <PolicyStatement web:about="http://dotherightthing.example.org/policy.xhtml"/>
>    <title>Ethical Business Shared Guidelines 1.1</title>
>    </PolicyStatement>
>  </ethicalPolicy>
> </Organisation>
> 
> 


A crude perspective on the example above will be to
see descriptions with many URIs and then determining 
primary-identifiers/foreign-identifiers. PersonalMailbox
could be Primary-identifier for b.rdf but 
foreign-identifier for a.rdf.  CorporateHomePage 
could be primary-identifier for a.rdf and foreign-identifier for c.rdf.

Following the route to describe entities and (reification) relationships with 1:N or M:N 
restrictions, one can
derive the most suitable description formats 
and use that as a model or meta-information.


> 
>        (Q1) What are the technology interests of persons who own
>     companies that have an ethical policy
>        committment to the policy stated in the document
>     http://dotherightthing.example.org/policy.xhtml 
> 


Relational databases resolve queries in a join engine
which could as well be a repository and 
an engine for resolving queries.
But RDF/XML queries can otherwise be 
resolved even with an adhoc join engine in transient
memory.

--regards,
--ssarkar@ayushnet.com
Received on Thursday, 4 January 2001 11:11:17 GMT

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