RDA Elements and sub-elements

[Jon Phipps]

Folks,

We're finally getting around to addressing an issue that Alistair raised
late last year [1].

"...Not directly related to any scenarios, I found that rda:placeOfCapture
is a sub-property of rda:placeAndDateOfCapture, which doesn't look
right. This looks like a case where Tom Delsey's "sub-elements"
pattern got wrongly translated to RDF sub-properties, where rather it
should be modelled in RDF as an n-ary relation."

This resulted in a discussion that culminated in a recommendation [2].

"...
For each RDA element X which has sub-elements Y, Z, ... generate
 an RDFS class C whose name is based on X, state the range of X as C,
 and state the domain of Y, Z, ... as C.

This is exactly what Mikael is suggesting we do, I believe.

E.g. for RDA element "publicationStatement" and sub-elements
"placeOfPublication", "dateOfPublication", I would generate the
following RDF schema fragment:

rda:publicationStatement rdf:type rdf:Property .
rda:placeOfPublication rdf:type rdf:Property .
rda:dateOfPublication rdf:type rdf:Property .
rda:PublicationStatement rdf:type rdfs:Class .
rda:publicationStatement rdfs:range rda:PublicationStatement .
rda:dateOfPublication rdfs:domain rda:PublicationStatement .
rda:placeOfPublication rdfs:domain rda:PublicationStatement .

So we have...
1. added domain and range to the standard registry schema attributes for
rdfs:properties and rdfs:subProperties
2. created both a class and a property whenever an rda element is composed
from 'sub-elements'
3. Made sure that the rda element property has a domain of the element class
4. Made sure that the 'sub-element' properties are not sub-properties and
have a range of the element class

We added some instructions to the class that will help _people_ create
applications that can construct and parse the composite elements. For
instance the instructions for Publication Statement are:

"This class has been created to define the Syntax Encoding Scheme for the
RDA Publication Statement composite string. The Publication Statement is
composed of an ordered, concatenated list of properties:
- Place of publication
- Parallel place of publication
- Publisher's name
- Parallel publisher's name
- Date of publication"

Obviously this draws in some elements of what we often think of as an
Application Profile, but it doesn't seem out of place in this context. One
of the goals of the Registry is to act as a bridge between the XML document
model and the RDF data model and one of the things that's also currently
missing is a sensible way to express this concept in an XML Schema and we
hope to pull some of that together as we implement AP registration.

Diane is adding/updating the list of element/sub-elements and I'll be
updating the sub-optimal (to put it mildly) RDF output shortly.

Cheers,
Jon Phipps

[1]
https://www.jiscmail.ac.uk/cgi-bin/webadmin?A2=ind0812&L=DC-RDA&T=0&F=&S=&P=22047
[2]
https://www.jiscmail.ac.uk/cgi-bin/webadmin?A2=ind0901&L=DC-RDA&T=0&F=&S=&P=12330