A schemeref element references another subject scheme map. Typically, the referenced subject scheme defines a base set of controlled values; the referencing map then extends the base set of controlled values. The values specified in the subject scheme maps are merged; the result is equivalent to specifying all of the values in a single map.
See appendix for information about this element in OASIS document type shells.
- map/topicref subjectScheme/schemeref
The following attributes are available on this element: Universal attribute group, Link relationship attribute group (with narrowed definitions of href, format, and type, given below), navtitle and query from Topicref element attributes group, outputclass, keys, and keyref.
- A pointer to the resource represented by the topicref. See The href attribute for detailed information on supported values and processing implications. References to DITA content cannot be below the topic level: that is, you cannot reference individual elements inside a topic. References to content other than DITA topics should use the format attribute to identify the kind of resource being referenced.
- On this element the format attribute sets a default value of "ditamap", because the purpose of the element is to reference a ditamap document. Otherwise, the attribute is the same as described in Link relationship attribute group.
- Describes the target of a reference. For the schemeref element, this value defaults to "scheme", because the element is expected to point to another subject scheme.