This page is a subpage of CMDI 1.2

Attribute related changes in CMDI 1.2: Executive summary

This page provides an executive summary of the issue and proposed solution fully described in CMDI 1.2/Attributes.

Issue description

There are two problems with attributes in CMDI 1.1:

1. In CMDI 1.1 attributes are always optional. This does not allow for mimicking of constraints of existing models (TEI header for example has mandatory attributes). Also it poses a needless restriction.
2. All attributes in CMDI 1.1 instances are in no-namespace, this counts for both attributes defined in the component/profile specification and the CMDI common attributes (@ref and @componentId) which have special semantics. Currently, the Component Registry and schematron rules check for the presence of attributes with these names and rejects them. A better solution would be to allow any name for custom attributes and move the reserved attributes into a dedicated namespace.

Description of proposed solution

Mandatory attributes

Add an element 'required' to the attribute definition in component specifications. If set to true, this translates to an additional attribute use="required" in the XSD.

Generic attributes to CMDI namespace

Leave custom attributes without namespace and put the following attributes in the same namespace as the elements, namely ​http://www.clarin.eu/cmd/ (an obvious namespace prefix would be cmd):

• ref
• componentId