Hi Matthew.
You questions below induced me to think the matter through once more.
Below is an attempt to illustrate my proposal with examples.
Your comments are very welcome - and useful.
1. Metadata Vocabulary
======================
Assume, that farmer Joe has declared the following vocabulary (Namespace) -
by means of RDF Schema or otherwise:
Object Class: CID=Fruit. Superclass=Entity
Object Class: CID=Apple. Superclass=Fruit
Object Class: CID=Pear, Superclass=Fruit
Property: PID=Taste. Domain=Fruit. Range=("Sour", "Sweet")
Property: PID=Colour. Domain=Fruit. Range=("Red", "Green")
2. Metadata Instance
====================
Being a forward-looking businessman, the Joe has established a ZNG Server
with information about his products.
In reply to a query about his products, he informs that apples are Red and
Sweet, while Pears are Green and Sour.
Joe has not bothered to declare a special format for his information. So he
just defaults to the RDF Serialization Syntax:
<?xml version="1.0" encoding="UTF-8"?>
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"
xmlns:gs="http://FarmerJoe/Meta/GreenStuff/">
<rdf:Description rdf:about="http://FarmerJoe/Products/Apple/">
<gs:Taste>Sweet</gs:Taste>
<gs:Colour>Red</gs:Colour>
</rdf:Description>
<rdf:Description rdf:about="http://FarmerJoe/Products/Pear/">
<gs:Taste>Sour</gs:Taste>
<gs:Colour>Green</gs:Colour>
</rdf:Description>
</rdf:RDF>
3. Something Else
=================
Do you think, that this would be practical, i.e. to just reference the RDF
Serialization Syntax and the Vocabulary Namespace?
- Or do you have a better solution to the problem of how to format metadata
without a predefined format?
Best regards,
Poul Henrik
-----Original Message-----
From: Matthew Dovey [mailto:[log in to unmask]]
Sent: 26. september 2001 13:08
To: [log in to unmask]
Subject: Re: ZNG, RDF Syntax and RDF Schema
Poul,
So by "default" format are you suggesting that
a) ZNG recommends that anyone with a vocabulary (such as Ray at present)
should use RDF to specify an XML instantiation of that vocabulary.
Providing that the structure of this XML instantiation can be given a
unique identifier (a URL), we can use this as the RecordSchema
designator in ZNG
or
b) the RecordSchema in the ZNG Request or Response could just reference
a vocabulary - in which case the XML instantiation is derived from the
vocabulary in RDF. This assumes that given a vocabulary it is possible
to derive a single or canonical RDF structure (i.e. how do we cope with
two servers having very different RDF expressions of the same
vocabulary?)
or
c) something else?
Matthew
|