[tdwg-tapir] TAPIR namespace and versioning
Renato De Giovanni
renato at cria.org.br
Wed Aug 16 02:56:26 CEST 2006
It's always good to know what OGC is doing and try to learn from their
experience. However, they are not the only ones working with XML Schemas.
And if you look at other groups you'll see that almost everyone uses
either version numbers or dates in the namespace (just look at the
namespaces declared in the <schema> element of tapir.xsd).
I know that "namespaces are not intended to solve crashes among
semantics", but they do provide a way to say that <ns1:myelement> is
fundamentally different than <ns2:myelement>, that was my point. I'm not
sure if the example I gave was a good one - of course I wouldn't like to
see this kind of difference between two TAPIR versions. It was just an
Yes, you can't validate a document without having the schema. But you
could have the schema for some other reason without needing to read it
from the schemaLocation. Actually I don't think it's safe to always trust
the schemaLocation of documents (it should be possible to try to feed an
application with an "alien" document that has a known namespace pointing
to a fake schemaLocation... not sure how far this could go).
> -Namespaces only change when there is a backwards compatibility problem.
> -We add the version attribute to the schema so that we can keep track
> of different versions.
Agreed. But when time comes, we just need to clearly define what kind of
changes would mean breaking backwards compatibility.
> And I would include (I dont know if you agree on this)
> -Use 2 numbers in the namespace and 3 in the version and keep them
Could be one or more numbers, or dates... it's just an identifier. I'll be
happy with any of the available options, even the current one.
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