Comments on "Dspace History System: Descriptive Note" of 2003/May /14

Identifiers: section 3.2
========================

It would be valuable to decide on the SIMILE policy for naming things
(including the allocation of URIs) outside of the History Store work as well
so that a common policy applies throughout the system.


Allocating URIs
---------------

The history system has to work with URIs external to the history system and
also to allocate URIs for information it creates.  It will have to cope with
external resources in any (legal) form : handles, http URLs, URNs, bNodes
with identifying properties.  Some of these may well not have been allocated
by SIMILE at all and were previously allocated.  The History Store (and
elsewhere in SIMILE) needs distinctly identify each concept as objects are
created and changed.

When the History Store does create "objects" it would be good if they were
GETtable.  If there is a metadata record
http://thisInstallation/collection/1711/101 for an object
http://example.org/aBook then having "GET
http://thisInstallation/collection/1711/101" working would be appropriate
returning RDF if asked for application/rdf+xml.  This would need pulling the
RDF out of the database for a plain GET if there is no data duplication and
hence chance for inconsistency.

URIs and scope
--------------

Specifically on database identifiers: if a value is a key into a local
database then this shouldn't be a URI because it is not a global 

In the phone conference, there was a comment that the same base is used for
all DSpace installations, not a different base for different installations,
so turning bitstream ID 202 into a URI as
http://www.dspace.org/bitstream/1721/202 is a global transformation. 
(It makes no such statement in the History Store document.)

By using the recommendation of type information (3.1.3) allows the use of
typed bNodes for modelling such database keys.

.................
@prefix ds: <http://www.dspace.org/namespace#>

[] rdf:type ds:bitstream ;
   ds:databaseId "202" .
.................   
<rdf:RDF
    xmlns:ds="http://www.dspace.org/namespace#"
    xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
  <ds:bitstream>
      <ds:databaseId>202</ds:databaseId>
  </ds:bitsream>
</rdf:RDF>
.................

Alternatively, and better, if there is a installation-local base we can
follow the recommendation in section 3.2.3 SIMILE can allocate a URI
(example including typing recommendation):

.................   
@prefix dspace: <http://www.dspace.org/namespace#> .
@prefix rdf:    <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .

<http://thisInstallation/dspace/collection/1721/113>
      dspace:logo
            <http://thisInstallation/dspace/collection/1721/202> .

<http://thisInstallation/dspace/collection/1721/202>
      rdf:type dspace:Bitstream .
.................   
<!-- With typing information -->
<rdf:Description
      rdf:about='http://thisInstallation/dspace/collection/1721/113'>
  <dspace:logo>
	<dspace:Bitstream
      rdf:about='http://thisInstallation/dspace/collection/1721/202'/>
  </dspace:logo>
</rdf:Description>
.................   


	Andy

Received on Thursday, 15 May 2003 06:49:01 UTC