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CMDI 1.2 for repository managers/metadata providers

CMDI 1.2

Information for repository managers/metadata providers

What is CMDI 1.2?

See the page on CMDI 1.2 for general information about CMDI 1.2.

How does CMDI 1.2 affect me?

CLARIN's metadata infrastructure has been adapted to support both CMDI 1.1 and CMDI 1.2. All new CMDI profiles can be instantiated as CMDI 1.1 or CMDI 1.2 records. Your repository software may support both versions, but most likely at this stage only supports CMDI 1.1.

If your repository produces CMDI metadata on basis of another type of representation (e.g. in a relational database, another metadata format or other XML format), the impact of adding CMDI 1.2 support is relatively low (see below). Note that this is not mandatory for maintaining compatibility with the 'core' infrastructure, as the VLO supports both versions of CMDI.

If you accept CMDI submissions directly into you archive, there is the possibility that you will receive CMDI 1.2 submissions. Your repository should at least distinguish between incoming CMDI 1.1 and CMDI 1.2 records (see "Should I take action immediately?"). You may choose to only support submission of one version of CMDI and reject the other, or only one - for example, accept CMDI 1.1 and convert it to CMDI 1.2 before further processing if you prefer to store only records that adhere to a single CMDI version.

Should I take action immediately?

If your repository produces CMDI but does not process incoming CMDI, there is no strict need for immediate action. If your repository accepts submission of CMDI metadata, it is advised to at least implement CMD version detection to deal with incoming CMDI 1.2 metadata in a more or less graceful way. This can easily be done on basis of the 'CMDVersion' attribute on the root node of a record. Also, the namespaces of the common CMDI "envelope" is different: CMDI 1.1 has http://www.clarin.eu/cmd/, while CMDI 1.2 uses http://www.clarin.eu/cmd/1.

How can I switch to CMDI 1.2?

If your repository produces CMDI metadata on basis of another type of representation (e.g. in a relational database, another metadata format or other XML format), it can be made to produce CMDI 1.2 instead of, or in addition to CMDI 1.1 with an additional transformation, either on basis of the source format or as an additional step after the existing CMDI generation (using the upgrade stylesheet from the CMDI toolkit).

If your repository uses CMDI as its 'canonical' format, you can either choose to completely switch by upgrading these records once (in batch) or keep using CMDI 1.1 and provide CMDI 1.2 by means of conversion - either on the fly upon request or at some earlier stage before serving the result). If you convert all of the metadata in your repository once, you can use the conversion utility from the CMDI toolkit for that. There is no standard solution for a "downwards" conversion of instances, so if you wish to keep providing CMDI 1.1 additionally, you will have to implement your own conversion (which can be quite straightforward depending on the profile(s) you are dealing with).

Depending on the exact way you are providing your metadata via OAI-PMH, it should be possible to configure your software to offer both CMDI 1.1 and CMDI 1.2 metadata, assuming that you have ways of producing both.

Additional and more detailed information that can be relevant to adapting repositories to CMDI 1.2 can be found in the subsection "How can I switch to CMDI 1.2?" of "Information for software developers".