[SEEK-Taxon] Thoughts on GUIDs

[Beach, James H]

Completely independent of the choice of identifier schemes, is the
question Nico, Rich and Dave have been tangoing around-- whether the
identifier should contain explicitly or implicitly any information about
the identify or the relationship of a concept to something else.
Embedding version numbers in ID's is additional information, i.e.
metadata, about the taxon concept that may be present nowhere else.  One
of the strongest arguments for the evaluation of 'artificial' or
'surrogate' key fields in a database context is that the 'key' should
not contain any implicit or explicit information about the object being
identified, other than its identity!
 
If the key itself has information then you will inevitably run into a
situation where the key will need to be changed because something about
the information represented by the key value has changed or is in doubt
or is a matter of interpretation, (thus losing the temporal uniqueness
of the GUID).  If for example, we decide to embed version numbers within
the GUID, then there will be relationships between GUIDs that need to be
maintained and respected and modeled as a consequence of the version
numbers themselves (sort of an embedded data model within the ID), which
adds another layer of abstraction to the whole enterprise of managing
concepts.  Instead of just worrying about mapping the taxonomic
relationships among concepts using unique IDs as the handles, such as in
the recent examples, one now has to verify that the subkey/version
identifiers are accurate (and that may be a matter of differing
interpretations) and related in the appropriate way that corresponds to
the taxonomy.
 
I would recommend that versioning be handled outside of the key or ID.
Let resolver services deal with version differences based on the
metadata, don't hard code relationships among concept versions in the
identifier.
_____________________________
James H. Beach
Biodiversity Research Center
University of Kansas
1345 Jayhawk Boulevard
Lawrence, KS 66045, USA
T 785 864-4645, F 785 864-5335




 
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