RE: [Digir-dev] Question on DiGIR Darwin Core and uniqueness of Catalog Numbers

[Blum, S. <sb...@ca...>]

In the context of DiGIR, "resource" and "CollectionCode" are not =
equivalent.
This enables a resource to encompass many collections (where a =
collection has
one and only one CollectionCode).  Many cases exist in the museum world =
where
a single collection management unit (i.e., department) manages several
collections, which are distinguished by different collection codes.  =
Catalog
numbers are duplicated across collections. =20
=20
It is tempting to say that a collection management unit corresponds to a
resource, but that's not right either.  A resource is intended to mean =
an
information resource -- a group of similar records that you can query =
and get
back a subset of records.  People and instititutions already have ways =
in
which they group their records into information resources.  Having =
multiple
resources under a DiGIR provider creates a separation of the distributed
query technology from the way people group their records into resources;
there doesn't need to be a one-to-one correspondence between provider =
and
resource.=20
=20
I also want to point out that a provider does not correspond to an
institution.  Many cases exist where an information resource is =
"provided"
(exposed via DiGIR) by a different organization than the one that =
maintains
it.  Therefore Dave is correct in saying that the combination of =
institution
code, collection code, and catalog number is required to identify any =
record.

=20
-Stan
=20
=20
-----Original Message-----
From: dig...@li...
[mailto:dig...@li...] On Behalf Of =
Donald
Hobern
Sent: Monday, May 10, 2004 4:18 AM
To: DiG...@li...
Subject: [Digir-dev] Question on DiGIR Darwin Core and uniqueness of =
Catalog
Numbers



	I'd like to find out how different projects have viewed
CatalogNumbers.  I had assumed that CatalogNumbers should be unique =
within
any DiGIR resource and hence that the CatalogNumber should serve as a =
unique
key to retrieve the record again from that resource.

	=20

	I have just found a provider which is reusing the same CatalogNumber
for different records but with a different CollectionCode for each.  =
Looking
at the DwC documentation this seems valid.  Indeed it would seem to be =
valid
to have records sharing the same CollectionCode and CatalogNumber =
provided
that they have different InstitutionCode values.  Should clients of =
DiGIR
resources always provide all three of these concepts when they issue a =
search
request for a given record?  Or is there an unwritten assumption that
CatalogNumbers should be unique on their own?=20