[silva-dev] Silva export and metadata
schluep at ethz.ch
Wed Aug 16 15:21:56 CEST 2006
> One behaviour we stumbled over recently is that in a Silva export the
> actual value of metadata is sticked to the documents (and objects)
> exported. This leads to unexpected results with acquired metadata
> values when the objects are imported in a different context. Let's
> imagine a layout whose colours are defined by a metadata value. Now if
> we export a document from an environment characterized by a blue
> colour and imported in a red environment, most probably we expect the
> imported document to be displayed in a red environment too. However,
> as the formerly acquired metadata value for the colour (blue) now is
> sticked to the document, the document's new display colour is still blue.
This is an issue I have pointed out earlier, i.e. at the Vienna sprint.
To me the problem is caused by using the metadata system for different
type of data: (1) "real" metadata describing contents, and (2) settings
information for layout control (as is done quite intensively in the ETH
"Real" metadata should remain attached to the contents when it is
imported into another context (e.g. another Silva site), even if the
metadata has been acquired. The problem with acquired metadata has
already been discussed earlier (see "[silva-dev] Import/Export of
Acquired Metadata", 2003-08-15 and the following thread): On the one
hand, if whole containers are exported and imported the acquisition
should work as in the original, from where the container has been
exported (changing the a value in an imported container should still be
acquired by the content objects contained in that container if that
value has been acquired in the original). On the other hand, the
metadata should be imported and attached to the contents, even the
metadata is acquired but its value is not specified anywhere in the
container tree being transferred (because the value has been defined in
a container higher up in the hierarchy, e.g. the Silva root).
In my experience, layout information being acquired generally shouldn't
be transferred (Benno's example demonstrates this quite nicely).
However, AFAIK Silva already has started to distinguish content metadata
and other settings by providing "settings..." and "metadata..." buttons
in the metadata tab. If content metadata and layout setting information
are clearly separated the acquisition issue can be solved in a clean way.
Thus, to me there are two issues:
1) Export and import of containers with acquired metadata for contents
2) Export and import of settings information that have been acquired.
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