David Powell wrote:
But you can't then expect to merge two different instances of the entry under this model using simple RDF graph merging, because the model is an over-simplification.
Eg: If you merged:
<entry> <id>http://123</id> <date>2005-02-03</date> <seismo:magnitude>7</seismo:magnitude> </entry>
and
<entry> <id>http://123</id> <date>2005-02-04</date> <seismo:magnitude>7.5</seismo:magnitude> </entry>
... you would get:
<entry> <id>http://123</id> <date>2005-02-03</date> <date>2005-02-04</date> <seismo:magnitude>7.5</seismo:magnitude> <seismo:magnitude>7</seismo:magnitude> </entry>
Not very useful.
That's a versioning problem. While I haven't found basic RDF to be useful for that, I could imagine finding an 60% solution with something like OWL. XML is of no help here. The usual answer is to use a version control system to record state in time series or allow update semantics to your persisted representations if you don't care about past state.
Incidentally I do believe that being able to track state or trends in a time series fashion has commercial value in the syndication market.
cheers Bill
