W3C home > Mailing lists > Public > www-rdf-interest@w3.org > February 2000

Re: Schemas using schemas.

From: Pierre-Antoine CHAMPIN <champin@bat710.univ-lyon1.fr>
Date: Wed, 23 Feb 2000 12:57:30 +0100
Message-ID: <38B3CB2A.7327BFDE@bat710.univ-lyon1.fr>
To: Pete Cliff <lispdc@ukoln.ac.uk>
CC: www-rdf-interest@w3.org
Pete Cliff wrote:
> How do I define the namespaces in the rslpcld schema? My initial thought
> is to include a "xmlns:" line for each of the schemas used.

this is the right solution

> However if
> this simply "#includes" the properties of other schema into the rslpcld
> schema then the rslpcld schema would be defined in terms of a number of
> undesirable properties.

this is not an #include ; this is only a shortcut, so you don't have to type the whole URI of other schemas each time.
If your RDF parser want more details about the properties you use, it will retrieve corresponding schemas ;
whether it will store the whole schema or only triples related to the properties you use is an implementation choice,
you can't mkae hypothesis on it.

> My second thought is to copy the relevant property definitions from their
> source locations into the rslpcld schema. However, this leaves a problem
> of version control. If I copied, for example, dc:identifier and
> subsequently the dc:identifier definition changes, the copy used as part
> of the rslpcld schema is out of date.

You simply can't !
If you redefine properties in your own schema, they won't have the same expanded name,
since the namespace will be you schema's, not the original schema's.
So they simply won't be the same, and you loose the benefit of interoperability.
(remember that the namespace prefix, e.g. "dc:" in "dc:identifier" or "rdf:" in "rdf:type" is NOT important,
 you could use any other prefix instead - what counts is the schema URI into which they expand,
 given by the value of xmlns:<prefix> attribute)

 Hope this is clear enough


--- Quid quid Latine dictum sit, altum viditur
    Whatever is said in Latin sounds important.
Received on Wednesday, 23 February 2000 06:59:10 UTC

This archive was generated by hypermail 2.4.0 : Friday, 17 January 2020 22:44:22 UTC