Version 3 (modified by 10 years ago) (diff) | ,
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This page is a subpage of CMDI 1.2
MdType instance header element
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MdType instance header element
- The issue
- Proposed solutions
- Tickets
- Discussion
The issue
Originally described in CmdiCollectionsIdentification
Due to the difference in granularity it might be good to be able to select CMD records of a specific granularity, e.g., collection or item level.
Proposed solutions
First solution: MdType header element
A new header element that indicates the type.
Pros
Easy
Cons
There can be a tendency to keep on extending the header instead of using CMDI's flexibility.
Centre impact
- Affected tools
- Impact on instances
Implementation examples
- Implementation on model level
- Implementation on instance level
Discussion
Axel?: This would work if we agreed on a fixed set of types, ideally with just two elements (collection, part_of_some_bigger_collection). But as always there is no sharp line to be draw between even those two values. E.g. for the Deutsches Textarchiv (a collection of digitalized complete printed book) one could argue that each part is also a complete and self-contained resource in its own right -- it just happens to have been arbitrarily chosen for inclusion in the Deutsches Textarchiv. Maybe we would need to introduce a third type 'archive' for cases like those?
Second solution: the one and only collection profile
One collection profile to be used by all.
Pros
Easy
Cons
Inflexible
Centre impact
- Affected tools
- Impact on instances
Implementation examples
- Implementation on model level
- Implementation on instance level
Discussion
Axel?: We shouldn't go this route. It's so inflexible that it is hard to imagine such a catch-all profile will ever stabilize. We would end up with a whole family of profiles anyway once profile versioning is in place.
Third solution: a mandatory collection component for collection profiles
Any collection level profile should contain a specific CLARIN collection component.
Pros
Easy, may have low impact if the component is optional (but can be detected in the schema)
Cons
What should be in the component?
Centre impact
- Affected tools
- Impact on instances
Implementation examples
- Implementation on model level
- Implementation on instance level
Discussion
Discuss this solution proposal in this section
Fourth solution: the profile root uses a data category from a collection relation set
The profile root should use one of the data categories from a specific collection relation set in RELcat.
Pros
Easy, low impact
Cons
Data category might be unintentionally used
Centre impact
- Affected tools
- Impact on instances
Implementation examples
- Implementation on model level
- Implementation on instance level
Discussion
Discuss this solution proposal in this section
Fifth solution: collection level instances are harvested from a specific OAI-PMH set
Like done for web services collection CMD records can be explicitly requested by harvesting a center specific OAI-PMH set.
Pros
No need to touch CMD profiles or instances
Cons
VLO currently doesn't use endpoint information, i.e., the facet mapping can't select based on the OAI-PMH endpoint or set.
Centre impact
- Affected tools
- Impact on instances
Implementation examples
- Implementation on model level
- Implementation on instance level
Discussion
Axel?: No, this is a dirty hack, i.e. a tailor made solution for VLO harvesting outside of the CMDI framework proper. Collection information must be expressed within the CMDI framework so that it is available not only at harvest time but also within MD instances.
Tickets
Tickets in the CMDI 1.2 milestone with the keyword mdtype:
Discussion
Discuss the topic in general below this point