[silva-dev] Silva export and metadata

[Samuel Schluep]

Hi altogether

> 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 
Layout product).

"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.

Best regards
Sam