3365RE: [TaxoCoP] data modeling and taxonomy
- Jan 5, 2010
Heather, Gabriel, John, Keith & anyone else who's following this thread:
I'm still feeling my way around these kinds of issues (have been for years), and have no hard-and-fast solutions. However, I do have some 'working hypotheses' which I find to be helpful. I'll refer to them as I respond to a few points made by John, Keith and Gabriel.
Firstly, John is quite right in pointing out that both data models and taxonomies are necessarily bounded. Who'd want to undertake a data model or a taxonomy of *everything*? Well, I suppose Melville Dewey, UDC, LCC have all attempted it, with varying degrees of success. But that's a topic for another day. In an organizational context, both data models and taxonomies need to be restricted to a specific domain, if only for practical reasons.
John also says:
> For example, if all of the 'entities' that a data modeller wanted to use were already classified by a taxonomist and resided in a master data management inventory, then a sort of symbiotic relationship could exist between the necessarily narrow application of the data and the universal 'connectivity' of a fully faceted business vocabulary. <
I see this as the role of the 'over-arching ontology which expresses the context of both data model and taxonomy', to quote my own post. The ontology, developed first, ensures that both data modeller and taxonomist are singing from the same hymn sheet. That will also prove of great benefit to data warehouse developers, document managers, records managers and information architects, further down the line.
Keith says that he finds taxonomies are regarded as:
> "THE solution" rather than being viewed as "A solution" or part of a larger system of models and decision-making depending on the nature of the enterprise <
Taxonomies have been over-egged. Many in the field think 'taxonomy' first and context later. IMHO bad! Build the ontology first, then do your data modelling. Then you'll have done a PoC (Proof of Concept) for the domain - identifying the entities which are important, their important attributes (for the data modellers) and a first lead-in to the language people use to refer to them (for the taxonomists). Using both the ontology and the data model, define the key attributes which different communities regard as important to them when they want to access and process information. That gives you a metadata application profile for each community which can be aggregated into a corporate metadata profile. Only then do you look at each attribute in each profile and decide how it is to be populated. Sometimes, it will be an /ad hoc/ value; sometimes the value will be drawn from a fixed, flat list; sometimes the value will be drawn from an organized, maintained hierarchy of values - a taxonomy. For me, the metadata profile comes first. A taxonomy only becomes relevant if a metadata element requires it.
> (I said "ontology / taxonomy" in the above because I'm not clear myself whether our CM does satisfy a full definition of "ontology"; for example as yet we have no mechanisms for making inferences). <
My 'working hypothesis' in this respect does not include the need for ontologies to enable the making of inferences. That is a requirement of strict 'ontologies' in the Semantic Web sense. For me, ontologies provide the context for ensuring that information and knowledge management structures and systems are coherent and interoperable.
> Getting at just where taxonomy, data modeling, and ontology specification begin, end, and overlap is really welcome. <
Again, my 'working hypothesis' is that ontologies come first, specifying the entities involved in an activity system, and their relationships. Data modellers will want to define the attributes of each entity and to characterize their relationships more rigorously, to enable their capture in the highly structured world of the DBMS, focused on logical consistency.
Information managers, on the other hand, are less data-focused and more user-focused, concerned with linking entities and their key attributes to the concepts - and the terms which represent those concepts - employed by workers. So - where appropriate - they build a taxonomy proposing terms to be used for those concepts, reflecting the taxonomic relationships inherent in any domain - generic, partitive, instantial. While the taxonomy can establish the entities (concepts) involved, and their relationships, it cannot dictate the terms which people use to refer to those concepts. Provision is made therefore for variance in terminology by developing a thesaurus, which allows people to search using their native term, and for back-end software to translate this into the 'preferred term' established by the taxonomy.
Hope that stimulates some thoughts. Meanwhile, where's Patrick Lambe in this thread? Patrick, I'm sure you have some informative views on these issues. Please join us.
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