[OAI-implementers] Moving records in and out of sets

Tim Brody tdb01r@ecs.soton.ac.uk
Thu, 23 Oct 2003 12:17:29 +0100

Greg Lindahl wrote:

>On Tue, Oct 21, 2003 at 09:33:59AM -0400, Caroline Arms wrote:
>>I'd like to concur with Thom that deletion/creation with a new ID would
>>"be a cure worse than the problem it is solving."  Records for OAI are not
>>usually managed independently.  The record IDs may play a role in managing
>>the content or be generated outside the OAI repository.  
>Allow me to second that, but from another side. One way that I'd like
>to use OAI is to take records originated at other sites, and add
>metadatda. I'd rather have records disappear and reappear silently
>than to change IDs, because a changed ID means that my added metadata
>is lost. But an ideal solution would have permanent IDs, and correctly
>include information about disappearing and appeard records in
>incremental updates.
This discussion is related to a previous one on this list:

Quoting Andy: "The item identifier is not the same as the resource 
identifier - because the item is not the same as the resource."

Therefore an OAI harvester should not rely upon the OAI identifier being 
in any way persistent for the resource. In a distributed system - 
especially with author-contributed resources - it is likely that there 
will be dupes, revisions, parts under multiple OAI identifiers and 
multiple repositories using the same OAI identifiers for different 

It is the *metadata* that describes the resource, not the OAI header, 
and it is the metadata that should contain a persistent, globally unique 
identifier for that resource (e.g. a DOI in DC.identifier).

I can't think of another solution to this set maintainence bug than 
"changing id" (flagging the old OAI item deleted, creating a new OAI 
item). Creating new sets  would seem to create more problems than it 
would solve (which is moving the goal-posts on harvesters).

All the best,