Linking MRTG elements

→ Information about submission as TDWG standard
→ MRTG Wiki Homepage
→ Current Schema Draft. This version is under internal review as part of the submission to TDWG.
→ Audubon Core Non normative document
→ MRTG Development History
→ MRTG Meeting Notes
→ MRTG Best Practices
→ XML Schema representation of Audubon Core
→ RDF representation of Audubon Core
→ MediaWiki Help

Sometimes repeatable MRTG attributes have a natural semantic relationship which can become ambiguous when one, or especially both, of them is repeated. Commenter and Comment are one example. If there are several mrtg:Commenter items, the schema up to v 0.8 does not provide any way to know which Comment was made by which Commenter.

There are at least these solutions to this. Suppose ItemA and ItemB must have an association.

• Solution 1. Require ItemA to be non-repeatable and declare that all the ItemB entries refer to it by definition

This solution requires a new MRTG metadata record for each distinct ItemA. That seems unscalable on several grounds:

For robustness, it requires a sound mechanism by which providers can associate the multiple metadata records with the same underlying resource, and a robust mechanism by which consumers can discover the related metadata records.

• Solution 2. Break the flatness goal of MRTG and define some class C of which ItemA and ItemB are attributes of an instance of of type C, and an isntance of C is one of the MRTG metadata items.

• Open World Solution. Ignore the problem in the normative document, and allow implementation constraint systems, e.g. suggested XML Schemas, RDF declarations, or others, to choose how to address this.

At this writing I think I prefer the Open World Solution, though it may encourage proliferation of implementation constraint systems. This seems to be the approach of Darwin Core. --BobMorris 13:55, 3 February 2010 (CET)